I touched on this subject in a post in the maintenance and repair thread.
However, in order to keep documentation of all the Mods I have made to our 30FE, I will post here the details of this latest Mod.
The original Coleman Mach 3 on my 30FE was only 3 years old, but it's efficiency had deteriorated drastically since last summer.
I tried most of the suggestions that others had posted over the last couple of years (relocating temp probe, cleaning coils etc), but none of them helped. The major issue was, the difference in temperature between the nearest vent and the intake was only 5 - 8 degrees instead of the 15 - 20 degrees it should be.
After posting my woes on this site, i got general agreement that Freon must have leaked out of the unit over time.
We made the decision to go ahead and replace the unit.
I found a replacement online at United RV in Texas for a reasonable price and ordered it.
It arrived within a week in one piece. I say that because I was NOT impressed with their packaging for shipping.
The AC unit was sitting (not attached to) on a wooden pallet, Surrounded by cardboard and wrapped on both ends in plastic wrap. Upon unwrapping the package, I discovered one corner of the shroud was dented in.
Fortunately, applying heat with a hair dryer on low to the dented in portion allowed it to pop back into place.
The actual replacement of the AC unit was fairly simple and took less than two hours.
I removed all the necessary parts from inside the RV (Filters, plenum, chute, mounting frame and bolts, duct divider, temp probe and the control box).
Unplugged the connector for the roof unit from the control box and the unit lifted easily off it mounting position.
With the help of my son, we tied a big rope around the unit and lowered it to the ground with the aid of an extension ladder.
Unfortunately, we were to busy at the time to take any photos.
We used the same rope (wrapped around the shipping container) and ladder to get the new unit up on the roof. While I didn't take any photos of the actual installation process, I did find this illustration that give the general idea of the process.
I then reused and reinstalled all of the parts I had removed previously, tightened down the bolts per the manual and plugged the new roof unit connector into the control box.
A quick note on the duct divider. When I originally started trouble shooting the cooling issue, I discovered that the duct divider had shifted and that cold air was leaking into the return air chute. I re-positioned it so it was in the proper location but that did not resolve my issue. It's something worth checking periodically if you notice a change in you AC. It tends to vibrate out of position from driving the rig. I actually used aluminum duct tape to hold it into place.
When the new unit is running, I now get up to 25 degrees in differential temperature.