E450 "clunks" when shifting from park

JGallagher · 10-07-2021, 02:38 AM

Hi Gang,
My 2017 Chateau Class C 23U has intermittently started to make a "clunk" sound when shifting from Park to D or R. Also the sound is sometimes heard when starting from a stop.
This is a new noise coming from the driveline.
Rig has 29000+ miles on it. 9000+ in the last three months as we are on the road.
The clunk is random, I cannot replicate it consistently.
As usual, I appreciate your thoughts and suggestions.
Thank you.
James

Chateau_Nomad · 10-07-2021, 04:36 AM

Have the drive shaft universal joints inspected at a reputable garage... by a reputable mechanic. While they're at it, just inspect the entire drive train, wheel bearings, bushings etc.

That's a fair amount of mileage... but definitely not high miles by any stretch. But you're at the point where things could be wearing/getting loose.

MJC62 · 10-07-2021, 04:50 AM

Do you also have a squeek when starting out? A regular squeek, squeek, squeek til the rig starts to gain speed is a dry U Joint.
The clunk could also be a u Joint though you say it is intermittent usually by the time a u joint starts to clunking it isn't intermittent you will get the noise about every time you put the truck in reverse, so it could possibly be a center carrier bearing the rubber grommet going bad.

HarryS · 10-07-2021, 04:57 PM

Could be nearly anything in the drivetrain. U joints, diff, flexplate to torque converter bolts. It needs to be inspected ASAP

Pillbox · 10-07-2021, 08:51 PM

Don’t forget the center carrier bearing

ducksface · 10-07-2021, 08:55 PM

There isn't anything we can guess at that will change the attending mechanics mind/view/diagnosis.

Chateau_Nomad · 10-07-2021, 09:28 PM

The wife said to have the mechanic check the muffler bearing...

Pillbox · 10-07-2021, 09:36 PM

Which muffler bearing, forward or aft?

Lt Keefer · 10-07-2021, 09:41 PM

The old Ford driveline clunk. I had a nice Ford pickup back in the 80s that suffered from this problem. Never could find out exactly what it was and never had an on the road failure.

10scDust · 10-07-2021, 11:29 PM

Maybe pinion to ring gear backlash.
It's against one side like last drove in reverse, then you switch to drive and clunk. Especially during start up, when engine is a bit cold, and rpms are higher.

Back in, put in park, set brake, turn off.
Return to driver seat, start up, release brake, holding brake pedal & put into drive....clunk!

JGallagher · 10-09-2021, 02:31 PM

Thanks everyone for the suggestions.
Interestingly, no clunks in the past 2 days.
I'll follow up with any further developments.

JIM SNYDER · 10-14-2021, 12:38 AM

Quote:

Originally Posted by JGallagher

Hi Gang,
My 2017 Chateau Class C 23U has intermittently started to make a "clunk" sound when shifting from Park to D or R. Also the sound is sometimes heard when starting from a stop.
This is a new noise coming from the driveline.
Rig has 29000+ miles on it. 9000+ in the last three months as we are on the road.
The clunk is random, I cannot replicate it consistently.
As usual, I appreciate your thoughts and suggestions.
Thank you.
James

Two obvious possibilities come to mind....
1/ Transmission internal problem
2/ Universal joint in the driveline.

Item 2 is easy to check out via your mechanic, straightforward to repair.
Item 1 is a bigger problem, trip to the transmission shop, good luck.

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