Schwintek Madness

[Vibeman]

Originally Posted by Judge

That is correct..... the motor is supposed to be centered by the four allen screws that protrude from the motor gearbox at the shaft end. They are also supposed to prevent the motor from twisting under load and theoretically not putting any load on the retaining screw.

However, because the motor is not securely held down vertically (that is the job of the retaining screw), the motor appears to have some lifting forces as it reaches its high-torque limits when moving the slide.

As the motor attempts to lift under load, it is putting force on the retaining small retaining screw. Given enough force it starts to damage and weaken the retaining screw. Again, with smaller / lighter slides, there is much less torque and upward force so it is not much of an issue but it is a different story with a large / heavy slide.

I have even had an independent LCI repair shop tell me they have seen the aluminum bend where the retaining screw is threaded into the motor. Now sometimes this is caused from obstructions, misaligned rollers, etc. but they also said it can happen with enough use of big slides.

As I've said, if you pull back the Bulb Seal inside the coach and observe the motor on a larger / heavier slide, you can see some movement when it is under its highest load.

If the four allen screws used for alignment were actually four vertical mounting screws, I think the Schwintek Mechanism could be more reliable. However, they tried to make the motor easy to replace in the field by not bolting it down and that just causes longer term wear and tear.

The two weaknesses with the Schwintel Mechanism is the motor mounting approach and a V-roller deisgn that is inadeqaute for a large / heavy slide.

The VRoom Mechanism addresses both of these deisgn limitations by incorporating a 4-point vertical motor mount and using high load bearings instead of a V-roller. Then they add a much better gear and track engagement.

Now I do agree that poor installation of the components like track alignment, mounting, loose screws, etc. will accelerate the problems people experience.

Another weakness of the Schwintek system from a Thor perspective is they use screws for the track mounting. I've read many posts about missing and loosening screws that wreaked havoc on slides. Some of this is because they over-tighten the screws at the factory. Vroom is using heavy duty rivets to secure the tracks so loosening screws is not an issue.

I also know from talking with LCI that the tolerances for the Scwintek Mechanism are 1/8" for all aspects of the slide and mechanism. Any of the components not within that spec will result in abnormal operation, wear and potential failure. From my perspective, needing an 1/8" tolerance for these coaches is wishful thinking.

One final word..... I also think that LCI's recommendation of holding the Extend / Retract button for 3 seconds to keep the motors synced contribute to this problem. When the motors stop because the slide is fully opened or fully closed and voltage is still being applied, the 500:1 motor is creating a very strong force on the entire motor mounting mechanism.

Vroom is redesigning the encoder on the top of the motor and the Controller to have more intelligence for keeping the slide motors synced so you don't have to hold the button for 3 seconds after the motors stop moving.

My goal here is just to provide information and give people options. After having the Thor Factory Service Center inspect my slide a year ago when I had it there for service at the end of my warranty and then talking to an independent LCI authorized shop when my slide failed during our recent trip, I decided spending $1000 - $2000 to fix the same system that might fail again made no sense.

Your analysis of the weak points in the Schwintek system sounds about right to me, and your conclusion that it is marginal at best for large heavy slides is probably correct too. Looking at your Vroom system, if (when?) I had to replace my Schwintek system I would most definitely consider them instead of Schwintek.

I disagree on one point, however. I don't believe that holding in the button for 3 seconds after retract actually applies continuous full stall force to the motor for as long as you hold the button. Rather I think it just ensures that there is enough time for both of the motor encoders to complete their homing routines and reset to a synchronized zero position. I could be wrong on this, but if I am and if you are correct and they do apply continuous full stall force until you decide to release the button, then I would add that to the list of weaknesses in the Schwintek system.

[Judge]

Originally Posted by Vibeman

I disagree on one point, however. I don't believe that holding in the button for 3 seconds after retract actually applies continuous full stall force to the motor for as long as you hold the button. Rather I think it just ensures that there is enough time for both of the motor encoders to complete their homing routines and reset to a synchronized zero position. I could be wrong on this, but if I am and if you are correct and they do apply continuous full stall force until you decide to release the button, then I would add that to the list of weaknesses in the Schwintek system.

I'm not so sure about that... I have heard my wood trim along the wll "creaking" at times while holding the button.

I'm not sure it is any different than if you tried to extend the slide with Slide Locks installed. That is why my coaches have all had a big yellow warning sticker saying "Remove Slide Locks Before Extending Slide!"

Now maybe the Controller is smart enough when retracting to just "check" for any movement versus applying constant 12V to the motor. Vroom doesn't seemt to think the LCI Controller has a lot of intellgence built into it.... one reason he has designed his own encoders to measure motor revolutions along with his own controller that is supposed to be "smarter" than LCI's. I guess we'll see....

[apr67]

I have seen this situation before, where the motor slips out of the retaining screw. (well in your case you say it sheared off, I'm not 100% convinced).

What I think happened is the motor wasn't all the way in the block when the retaining screw was installed. If it is zero torque is ever applied to the screw, its all on the 4 allen screws in the bearing block. In my case the motor would not slip down all the way into the collar it is supposed to and the retaining screw was just on the side of the motor.

[Judge]

Originally Posted by apr67

I have seen this situation before, where the motor slips out of the retaining screw. (well in your case you say it sheared off, I'm not 100% convinced).

What I think happened is the motor wasn't all the way in the block when the retaining screw was installed. If it is zero torque is ever applied to the screw, its all on the 4 allen screws in the bearing block. In my case the motor would not slip down all the way into the collar it is supposed to and the retaining screw was just on the side of the motor.

In my case the motor eventually bent the screw upwards from the motor trying to lift out of the bearing block. I installed the replacement motor and it was fully seated.

However, when retracting my 23’ and probably 1200+lbs slide, you could see the motor trying to lift and bend in towards the slide box under extreme torque.

[RACarvalho]

Originally Posted by Vibeman

I have a 2020 Hurricane 29m with a full wall slide and the Schwintek system. I am not an apologist for Schwintek, but I think at least some (and maybe even most) of the problems folks have are not really a Schwintek problem, at least not initially. People write something like "one end of the slide did not keep up with the other end while retracting/extending but we were able to push/pull it and get it to go in. We had to do this often and then after a while the cheap junk Schwintek motor/gear/bearing/rack/etc failed" Well, that scenario sounds to me like the very first time it happened something was binding, but the Schwintek was able to overcome it so the root cause, the binding, was not corrected, thereby overloading the Schwintek every time it was used, causing increased wear/damage and eventual catastrophic failure. If the slide did not bind when new, but started binding some time later, then the obvious conclusion is that something changed. It is possible the Schwintek system itself started binding, but I think it is much more likely that in most cases the THOR slide itself starts binding somewhere, causing the eventual Schwintek failure.
So far my slide operates smoothly and consistently every time I use it. I inspect it regularly and maintain it according to the mfg's recommendations. If I ever saw/heard/felt/or smelled anything unusual during inspection or during movement, even one time, I would try to identify the root cause and correct it ASAP. This requires paying close attention to everything, every time the slide moves. Installing a stronger, more robust (and more expensive) mechanism would allow the system to work at a higher load for a longer time, and that is a valid option, but does not really address the root cause, which is an increased load caused by binding somewhere in the system. Finding and fixing the root cause returns the system to it's normal load, which the original mechanism is designed to handle.
The OP wrote: "I find that the rear motor had sheared off the motor retention screw. The screw stops the motor from rising out of the bearing block" I am familiar with the screw and it's purpose and what the OP says is true. That little screw is not designed to take a heavy load and should never have to. The fact that it "sheared off" is only a symptom, not a cause of failure. It is indicative of another problem causing an unintended load on the screw.

Preventive maintenance prevents problems and the damage caused by them.
Reactive maintenance only corrects damage that has already occurred but does not address the root cause of the damage so it can happen again, and again.

I'm sorry buy I disagree.
I have a 2021 34R and my full wall slide system (Schintek) was fully replaced under warranty due to the same problems stated in this post.
One thing that was discovered was that the factory have not installed the system properly...
The new system works properly 80% of time but still bind randomly 20% of time.
I know the guys that did the repairs, the slide is within measure (+-1/8in tolerance) on all tracks and it still randomly binds.
I do the maintenance with the lub indicated by Lippert.
All rollers are adjusted properly, etc.

I am a mechanical engineer and agree with the Vroom guy.
Even before knowing what Vroom was doing I wrote to the Lippert rep and the Thor Warranty person that are working with me that the Schintek system is not a robust solution for full wall slide.
If the slide keeps randomly biding even with the new set , I'll go Vroom solution next year.

[Scubawise]

What lube do you use?
I do the maintenance with the lub indicated by Lippert

[MLP]

Originally Posted by Vibeman

I have a 2020 Hurricane 29m with a full wall slide and the Schwintek system. I am not an apologist for Schwintek, but I think at least some (and maybe even most) of the problems folks have are not really a Schwintek problem, at least not initially. People write something like "one end of the slide did not keep up with the other end while retracting/extending but we were able to push/pull it and get it to go in. We had to do this often and then after a while the cheap junk Schwintek motor/gear/bearing/rack/etc failed" Well, that scenario sounds to me like the very first time it happened something was binding, but the Schwintek was able to overcome it so the root cause, the binding, was not corrected, thereby overloading the Schwintek every time it was used, causing increased wear/damage and eventual catastrophic failure. If the slide did not bind when new, but started binding some time later, then the obvious conclusion is that something changed. It is possible the Schwintek system itself started binding, but I think it is much more likely that in most cases the THOR slide itself starts binding somewhere, causing the eventual Schwintek failure.
So far my slide operates smoothly and consistently every time I use it. I inspect it regularly and maintain it according to the mfg's recommendations. If I ever saw/heard/felt/or smelled anything unusual during inspection or during movement, even one time, I would try to identify the root cause and correct it ASAP. This requires paying close attention to everything, every time the slide moves. Installing a stronger, more robust (and more expensive) mechanism would allow the system to work at a higher load for a longer time, and that is a valid option, but does not really address the root cause, which is an increased load caused by binding somewhere in the system. Finding and fixing the root cause returns the system to it's normal load, which the original mechanism is designed to handle.
The OP wrote: "I find that the rear motor had sheared off the motor retention screw. The screw stops the motor from rising out of the bearing block" I am familiar with the screw and it's purpose and what the OP says is true. That little screw is not designed to take a heavy load and should never have to. The fact that it "sheared off" is only a symptom, not a cause of failure. It is indicative of another problem causing an unintended load on the screw.

Preventive maintenance prevents problems and the damage caused by them.
Reactive maintenance only corrects damage that has already occurred but does not address the root cause of the damage so it can happen again, and again.

Mine went out of sink. I always sink it every time I bring it in or out. I will not sink nor will it close fully at the bottom front. Just spent almost a year getting the thing rebuilt. Worked great for four trips. Do to my wife's health, we cannot go more than four to five hours away until it improves. Back in the local dealership. All three of the local independent shops have two to three months weight now. Under extended warranty so another $200.00 and time.

[RACarvalho]

Originally Posted by Scubawise

What lube do you use?
I do the maintenance with the lub indicated by Lippert

CRC Power Lube

[MLP]

Originally Posted by MLP

Mine went out of sink. I always sink it every time I bring it in or out. I will not sink nor will it close fully at the bottom front. Just spent almost a year getting the thing rebuilt. Worked great for four trips. Do to my wife's health, we cannot go more than four to five hours away until it improves. Back in the local dealership. All three of the local independent shops have two to three months weight now. Under extended warranty so another $200.00 and time.

Well I just reread this and I know it is wait and not weight! The delay at the dealership was do to COVID at THOR and then three weeks at the dealership do to COVID. The parts delay was do to COVID. Could not get the trucks to transport them. Then the tech routed the motor cable on the outside instead of the inside and it got caught in the guide wheel. This broke the outside columns rivets and all. Dealer then had to order all parts with a huge delay waiting for the parts. Two days to install when the parts came in. Do to all this they replaced all seals and gaskets, top, sides, and under. All looked showroom fresh inside and out.

[Vibeman]

Originally Posted by RACarvalho

I'm sorry buy I disagree.
I have a 2021 34R and my full wall slide system (Schintek) was fully replaced under warranty due to the same problems stated in this post.
One thing that was discovered was that the factory have not installed the system properly...
The new system works properly 80% of time but still bind randomly 20% of time.
I know the guys that did the repairs, the slide is within measure (+-1/8in tolerance) on all tracks and it still randomly binds.
I do the maintenance with the lub indicated by Lippert.
All rollers are adjusted properly, etc.

I am a mechanical engineer and agree with the Vroom guy.
Even before knowing what Vroom was doing I wrote to the Lippert rep and the Thor Warranty person that are working with me that the Schintek system is not a robust solution for full wall slide.
If the slide keeps randomly biding even with the new set , I'll go Vroom solution next year.

No need to be sorry, I disagree with you too. If you care to reveal exactly which points in my post that you disagree with I will address them.
Here is where I disagree with you:
You state "The new system works properly 80% of time but still bind randomly 20% of time." I maintain that each and every binding incident you have encountered has a root cause. There may be multiple reasons for the binding and those reasons may not always be consistent or apparent. Two variables that come to mind is the ambient temperature when the incident occurs and exactly how level and straight and square is the coach frame at the time of each incident. Just because something appears to be happening "randomly" does not mean the root cause is random. I stand by my statement in my post:
"If I ever saw/heard/felt/or smelled anything unusual during inspection or during movement, even one time, I would try to identify the root cause and correct it ASAP." I definitely consider a slide stall during operation, even once, to be unusual and I would investigate and identify the root cause, and correct it.

I might add that identifying and correcting every root cause of every failure of a system may not always be practical or economical. As I have already stated the Schwintek system may be marginal at best for a very large and heavy slide. Sometimes the prudent reaction to a continuing problem may be to just cut your losses and go with a more robust system.

[Judge]

To put things in perspective after the last several posts........

The Schwintek Slide Mechamism is a functional design. It is likely better suited for smaller and lighter slides and more prone to issues / failures with larger and heavier slides.

But here is where the rubber meets the road......

Coaches take a lot of abuse from leveling and driving down the road. There is a lot of twisting and torquing of the chassis and house structure on a regular basis..... there is no getting around that fact.

If a system is designed that requires a tolerance of no more than 1/8" out of spec to operate properly and without failure, it is unrealistic to expect that components are not going to move, flex, bend, etc. and potentially cause something to be outside of the operating spec.

Then factor in quality control and workmanship assuring that every slide built is within the tolerance spec and the slide box and slide mechanism is built, assembled and adjusted perfectly.... and that perfect adjustment lasting for a reasonable length of time.

At the end of the day, reliable slide operation is going to be like playing Russian Roulette.... especially as the size and weight increases.

I now have personal experience comparing the Schwintek Slide Mechanism with the Vroom Slide Mechanism. There is a visible difference in the designs of the two systems and the components used. The Vroom System is far more robust and has a much better chance of being reliable given the above dynamics I listed.

The RV Manufacturers and LCI literally bank on the fact that most people will use their new RV just a few times the first year and the system will last long enough while under the factory warranty. After the warranty is up, they are perfectly fine if the system fails because it means increased revenue from selling replacement parts. There is really no financial motivation to improve the design... or manufacturing practices.

The old saying..... "If you want something done right, you have to do it yourself" applies in this particular case.

If anyone has a Schwintek Slide Mechanism failure, I would highly recommend they look at the cost of fixing the side with the same mechanism and parts (which will likely cost between $1000 - $2000 per slide) versus installing a better designed and more robust slide mechanism for a little more money.

[RACarvalho]

Originally Posted by Judge

To put things in perspective after the last several posts........

The Schwintek Slide Mechamism is a functional design. It is likely better suited for smaller and lighter slides and more prone to issues / failures with larger and heavier slides....

That is exactly what I told Thor.

I told them I had two previous campers with Schwintek and they worked fine but the slides where way smaller and light than this current one. I told them I would not apply this system in any slide bigger than 15ft.
Not because pf weight but because of chassis twisting...

My point to them is the fact that almost always the motor that fails is the rear one and I explained to them the dynamics of a truck chassis and that the rear of the chassis is where you see the biggest twist between the chassis rails.
I have another not so small slide on the driver side that has the Schwintek system too and it works perfectly but that is because close to the front axle, where the engine is, the chassis twist way less because of the reinforcements for the engine...

The end of the chassis will twist a lot (compared to the portion of it just behind the engine) and that twist WILL lead to more than 1/8in difference and problems.

The twisting is not solved when you install the Vroom system but because the Vroom system is more robust, it may be able to handle the stress.

My questions about the Vroom are:
1 - For how long will it be able to handle that stress? (my Schwintek system was able to work properly for the first 5000 miles...)
2 - As the Schwintek , the Vroom system is attached to the wall so if the Vroom system is more robust and can handle the load, it is transferring that load to the wall: can the wall handle that or the wall will start to crack/twist?

Tks,

[RACarvalho]

Originally Posted by Vibeman

No need to be sorry, I disagree with you too. If you care to reveal exactly which points in my post that you disagree with I will address them.
Here is where I disagree with you:
You state "The new system works properly 80% of time but still bind randomly 20% of time." I maintain that each and every binding incident you have encountered has a root cause. There may be multiple reasons for the binding and those reasons may not always be consistent or apparent. Two variables that come to mind is the ambient temperature when the incident occurs and exactly how level and straight and square is the coach frame at the time of each incident. Just because something appears to be happening "randomly" does not mean the root cause is random. I stand by my statement in my post:
"If I ever saw/heard/felt/or smelled anything unusual during inspection or during movement, even one time, I would try to identify the root cause and correct it ASAP." I definitely consider a slide stall during operation, even once, to be unusual and I would investigate and identify the root cause, and correct it.

I might add that identifying and correcting every root cause of every failure of a system may not always be practical or economical. As I have already stated the Schwintek system may be marginal at best for a very large and heavy slide. Sometimes the prudent reaction to a continuing problem may be to just cut your losses and go with a more robust system.

Where I don't agree with you is in the point that you can correct this by troubleshooting everything and doing proper maintenance.
You can't fix something that is underdesigned for a specific application (see my post above about chassis twist).
And that is the reason the new schwinteck (3TRack) system in my coach is failing the same way the first one failed.
The full wall slide is a brilliant idea as it is the Schwinteck system but the schwinteck system have limitations (+-1/8 in of tolerance) and its application in a full wall slide is beyond its capabilities because the tolerance of the system is too tight for a place that moves too much like the rear of the coach.

That doesn't mean it will not work initially (mine worked fine for the first 5000 miles) but it means the system will not last a reasonable amount of actuations INDEPENDENT of maintenance / adjustments - the system will fail regardless.

One fact that I use to support my argument is that in almost all the cases (including mine where the factory installed the system slightly out of the the tolerance) the motor that fails is the motor at the back of the coach (where the chassis twist more) , the motor in the front works fine...

I'm friends with the dealer shop manager and the guy that worked on my coach and they confirmed to me that it is almost always the rear one where the problem happens....

Why the motor in the front don't fail? Why the motors in the short slide don't fail??? => They don't "see"/suffer with the amount of chassis twist induced stress that the rear have to handle...

As for maintenance, I have OCD and I'm a maintenance freak.
As I park my MH at home (can see it from my home office window )I keep "looking for trouble" all the time and have an extensive list of improvements that are being knocked down....
My wife once told me she wished I would take care of the house as I take care of the coach....

[chunker21]

Originally Posted by Judge

To put things in perspective after the last several posts........

The Schwintek Slide Mechamism is a functional design. It is likely better suited for smaller and lighter slides and more prone to issues / failures with larger and heavier slides.

.

Thus the inherent reason I will NOT have a full wall slide. It's too big, the structure of the body has too big of a hole carved into it, too much weight, and a formula for disaster for anyone who frequently uses the RV and systems. By that I mean frequently traveling and setups rather than twice a year in the annual snowbird north to south migration. When you look at the slide size in the larger Omni/Magnitude models, it's small compared to some of the tag axle DPs out there.

[RACarvalho]

Originally Posted by chunker21

Thus the inherent reason I will NOT have a full wall slide. It's too big, the structure of the body has too big of a hole carved into it, too much weight, and a formula for disaster for anyone who frequently uses the RV and systems. By that I mean frequently traveling and setups rather than twice a year in the annual snowbird north to south migration. When you look at the slide size in the larger Omni/Magnitude models, it's small compared to some of the tag axle DPs out there.

Every major manufacturer have a model with full wall slide because the customers like the space they can get with that.
The problem is not the full wall slide but the system that is used to move it.
Tiffin, Forest River, etc don't use schwinteck system on full wall slide and I would bet that their reliability is better.

This is the second RV we have with opposed slides and we love the big slide... Just the mechanism to move it needs to change...

[chunker21]

Originally Posted by RACarvalho

Every major manufacturer have a model with full wall slide because the customers like the space they can get with that.
The problem is not the full wall slide but the system that is used to move it.
Tiffin, Forest River, etc don't use schwinteck system on full wall slide and I would bet that their reliability is better.

This is the second RV we have with opposed slides and we love the big slide... Just the mechanism to move it needs to change...

FWS make a lot of room and I agree the mechanism is a major factor to problems. My other big issue is the hole in the side of the RV that accommodates that FWS. That hole means a weakened structure easily getting out of square especially if the RV isn't leveled properly prior to deploying the slide. Thor, the ultimate provider of the entry level RV, is going to cheap out on every opportunity. Slide mechanism is just one of many bottom end parts used. Bottom end works on small ones like the bedroom in the XG32, is adequate in our living area slide of 16', and totally inadequate in a larger FWS. But as stated, they bet the average owner won't use it that much and the mechanism won't fall apart until after the warranty is expired. Then it's not their problem, it's yours/mine/ours.

[RACarvalho]

Originally Posted by chunker21

FWS make a lot of room and I agree the mechanism is a major factor to problems. My other big issue is the hole in the side of the RV that accommodates that FWS. That hole means a weakened structure easily getting out of square especially if the RV isn't leveled properly prior to deploying the slide. Thor, the ultimate provider of the entry level RV, is going to cheap out on every opportunity. Slide mechanism is just one of many bottom end parts used. Bottom end works on small ones like the bedroom in the XG32, is adequate in our living area slide of 16', and totally inadequate in a larger FWS. But as stated, they bet the average owner won't use it that much and the mechanism won't fall apart until after the warranty is expired. Then it's not their problem, it's yours/mine/ours.

I agree that the FWS leaves, in theory, the MH box weakened by having a big hole there but you can design a cage with a big hole that is more rigid than another w/o it... It depends on the design....
Also, the entire thing is bolted to a chassis that will twist in first place ...
If the big hole of the FWS was weakening the structure to a point of concern, we would have problems in other areas like the cabinets attached to the wall/ceiling on the other side of the coach, etc.
Obviously the box structure is already designed to get to the rigidity that they want but the corners by the back end are where you expect to see more movement and +-1/8in of tolerance will not/is not making it...

As for the "cheap" aspect of it, I see it both ways:
First, obviously no one likes to pay for something that doesn't work so whatever doesn't work needs to be fixed.
Second, I'm glad that we still have in America companies that think and behave in the American "spirit". I explain:
In many countries, companies just gave up and assumed that RVs are for rich people so middle class can't afford to buy a MH there because they don't design them for middle class....
Here companies are still "American thinking" and designing things for the middle class budget...

Curiosity:
Does anybody knows what is the Motorhome "life" according to Thor??? <= That is what they should be designing for...
Just so you know:
BMW "life", according to them, is 100K miles, that is the reason they say, for example, that transmission fluid is for "life", it means the transmission will not fail within the first 100K miles!!!

[Scubawise]

Full wall slide camped 1st year ..
Motor failed replaced once.
Camped this summer 6 months on road 25 campsites..slide in and out no issues

Knock on wood.
Full winter trip starting Nov

[Vibeman]

Originally Posted by RACarvalho

Where I don't agree with you is in the point that you can correct this by troubleshooting everything and doing proper maintenance.
You can't fix something that is underdesigned for a specific application (see my post above about chassis twist).
And that is the reason the new schwinteck (3TRack) system in my coach is failing the same way the first one failed.
The full wall slide is a brilliant idea as it is the Schwinteck system but the schwinteck system have limitations (+-1/8 in of tolerance) and its application in a full wall slide is beyond its capabilities because the tolerance of the system is too tight for a place that moves too much like the rear of the coach.

That doesn't mean it will not work initially (mine worked fine for the first 5000 miles) but it means the system will not last a reasonable amount of actuations INDEPENDENT of maintenance / adjustments - the system will fail regardless.

One fact that I use to support my argument is that in almost all the cases (including mine where the factory installed the system slightly out of the the tolerance) the motor that fails is the motor at the back of the coach (where the chassis twist more) , the motor in the front works fine...

I'm friends with the dealer shop manager and the guy that worked on my coach and they confirmed to me that it is almost always the rear one where the problem happens....

Why the motor in the front don't fail? Why the motors in the short slide don't fail??? => They don't "see"/suffer with the amount of chassis twist induced stress that the rear have to handle...

As for maintenance, I have OCD and I'm a maintenance freak.
As I park my MH at home (can see it from my home office window )I keep "looking for trouble" all the time and have an extensive list of improvements that are being knocked down....
My wife once told me she wished I would take care of the house as I take care of the coach....

Your disagreement with me is, and I quote:
"Where I don't agree with you is in the point that you can correct this by troubleshooting everything and doing proper maintenance."
I do not know where you got your "point" but it was not from my post. As I have already stated more than once the Schwintek system is probably only marginally adequate for large slides. This means it is more likely to fail sooner on large slides than on small ones. Maintenance, as the word itself states, is only keeping things as they are. It does not improve poor designs. Neither does troubleshooting. My point is that if a system works initially, and you keep ALL components in the system as they were initially, then the system will continue to work. If anything changes due to wear, flexing, overloading, or any other reason then things may quit working sooner.
I think I get your point and I agree. If normal use of something puts enough strain anywhere on the system to cause any component in the system to fail prematurely, then the system is poorly designed and inadequate. I still maintain, however, that proper maintenance can extend the useful life of even a poorly designed system beyond what it would be if little or no maintenance were done.

[Chateau_Nomad]

After returning from our most recent trip I noticed a kitchen cabinet door not closing... as if the (non adjustable) hinges had slightly shifted. Something other than humidity had caused the doors to rub at the top edge.

So what changed? I had Big Foot levelers installed before this travel season started. I have considered that the torque stress possibly contributed?

That's only a W.A.G., but if frame torque/twisting is a contributing factor to that, how might it contribute to distortion of the full-wall slide room and components?

Something to consider...