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Isaac-1 · 02-06-2023, 02:38 PM

I have a 2002 P32 chassis Safari Trek in overall good condition that I plan on keeping for the foreseeable future that is about to hit 100,000 miles. I am strongly considering getting the 4L80E transmission rebuilt as preventive maintenance as from my casual observation it seems most people that report failures of these transmission in P32 chassis motorhome applications seem to see failures at around 110,000 miles or so. I have an estimate from a local trusted transmission shop (owner is a distant cousin) of $3,400 - $3,800 to rebuild a running 4L80E as a non-rush job with about a 1-2 month lead time to schedule it into the shop.

Am I crazy for considering this?

thanks Ike

TandW · 02-06-2023, 04:38 PM

Depends on whether you towed a tank with it or climbed Mt. Everest and what material you find in the pan. Happy trails and good luck with your decision!

donr103 · 02-06-2023, 10:14 PM

Are you original owner? How well have you done proper maintenance ? I and guessing that you have.. if you ask this question.. just depends on how hard you have pushed it.. is there any problems now.. like slow shifting.. and if you tow.. how heavy is toad?
The real problem with trans is heat.. and poor maintenance.. do you check trans temps.. if you do.. what is the hottest you have seen it? So Google transmission life vs oil temp and that will help you add one piece to the puzzle.. sorry for the questions but it is a good some of cash.. but even harder inconvenient.. then.. even finding a good shop where you will not have to keep returning for even more problems in future..
If I were you.. and just wondering about this.. I would call MONSTER TRANSMISSION .. check them out online.. if you plan to keep it.. just maybe a little more research.. they might have an upgrade.. I always dreamed of a auto trans with 5 speed now that gas is going back up.. you know it will not go down.. but that is me.. and even Allison is making a drop in 8sp that is supposed to be something else.. one thing you don't mention is converter.. I would have a new one put in.. that will add some.. do your research on those..
Good luck and keep us posted

Isaac-1 · 02-06-2023, 11:37 PM

I bought the coach which is on the 17,500 GVWR chassis in 2016 when it was at 74,000 miles, and have used it since then mostly traveling without a TOAD, but also towing since 2020 either a 4,300 pound Jeep Cherokee or a 2,300 pound Toyota Yaris. I had all the fluids changed on it including transmission fluid when I bought it. The previous owner kept good maintenance records, did about $10,000 worth of upgrades (mostly suspension, but also refrigerator, inverter, solar, etc.) and towed an unknown model of car, though they bought at the 54,000 mile mark, and had no maintenance records from before that time, as they bought it from the widow of the previous owner who was a traveling minister, and used the coach to go to church revivals, she knew nothing about the maintenance side of things. I do monitor transmission temperatures using a Scangauge II at least while in mountain travel, and try to keep Transmission temperatures below 230 degrees, preferably a lot below. Having said that on our last trip on a handful of times I heard a noise that might have been something slipping in the transmission when climbing steeper highway grades at speed in Arkansas and Missouri while towing the Yaris, this noise only happened a handful of times over about a thousand miles, and immediately stopped when I let off the gas. I was not able to intentionally reproduce it on other hills.

yeloduster · 02-07-2023, 06:38 AM

If you are going to change it you might consider this TRANSMISSION.

The hardest parts are figuring out how to make the transmission electronics play with the Workhorse electronics and the PRICE!

It give you 6 evenly spaced forward gears, a deeper first gear for more start off torque.

I have the Allison 5 speed in my MH but would really like the gearing of this transmission.

1972VWbus · 02-07-2023, 06:18 PM

First thing to check on the 4L80E is the trans connector on the side of the trans. Disconnect it and check for (red) trans fluid. There should be no fluid.

The connector is known to crack internally allowing fluid into the harness which will cause a host of trans issues. The fix is to replace the wire harness. Easy DIY job but requires dropping the pan.

If you do this it's also a good time to replace both shift solenoids (A & B) and turn the force motor up ~ 1/2 turn (clockwise). I would not replace or give thought to rebuilding the trans unless absolutely necessary.

Mark_K5LXP · 02-08-2023, 07:44 AM

Quote:

Originally Posted by 1972VWbus

If you do this it's also a good time to replace both shift solenoids (A & B) and turn the force motor up ~ 1/2 turn (clockwise).

Do you have any details about the 'force motor' (pressure regulator?). I've replaced my shift solenoids but still get occasional "stuck" codes. I know there's a TSB to sleeve one of the plungers which is a teardown of the valve body (what shop would even attempt that?) but if a "tweak" minimizes that issue I'd try that first. I hate the idea of a tranny swap for a valve body issue but no one fixes transmissions anymore, repair by replacement.

My opinion of doing a preemptive tranny swap is to leave it be. For a rig this old and high mileage, it's days are numbered. What I've experienced working on my P32 trying to source chassis parts is a PITA and only getting worse. Run it 'til it don't run, and move on.

Mark B.
Albuquerque, NM

1972VWbus · 02-08-2023, 10:19 PM

Quote:

Originally Posted by Mark_K5LXP

Do you have any details about the 'force motor' (pressure regulator?). I've replaced my shift solenoids but still get occasional "stuck" codes. I know there's a TSB to sleeve one of the plungers which is a teardown of the valve body (what shop would even attempt that?) but if a "tweak" minimizes that issue I'd try that first. I hate the idea of a tranny swap for a valve body issue but no one fixes transmissions anymore, repair by replacement.

My opinion of doing a preemptive tranny swap is to leave it be. For a rig this old and high mileage, it's days are numbered. What I've experienced working on my P32 trying to source chassis parts is a PITA and only getting worse. Run it 'til it don't run, and move on.

Mark B.
Albuquerque, NM

Have you checked the trans connector on the side of the trans. That is a well documented issue with the 4L80E and caused a host of shift issues. It unplugs from the trans. Pull straight off. Use some electrical contact cleaner to clean both ends well.

Have to find a shop near you that will do the valve body. It is doable with the tranny in situ. If you are ever in Grant's Pass, Oregon look up or stop by Jerry's Clutch & Transmission Service. He really knows transmissions, clutch, driveshafts etc...been in business 50 years.

I've not had to much difficulty finding parts for the 7.4 454 TBI but with the 8.1 Workhorse that is where one will start having trouble sourcing parts.

Isaac-1 · 02-09-2023, 01:18 AM

The shop I have in mind will diagnose and take things step by step, not just blindly pull the transmission. I am not sure how long they have been in business, but they have been at their current location for over 30 years, and the distant cousin that owns the place is in his mid 60's.

Ike

Mark_K5LXP · 02-09-2023, 06:58 AM

The connector is clean/dry. 99% of the time the trans works perfectly through all the gears, pulling grades, over temp and all the possible operating scenarios I put it through. It's a "good" transmission in terms of wear and performance, most trips there's no issue at all. But sometimes there's that odd combination of accelerating and a grade where it goes into limp mode (won't go higher than 2nd) and it sets a DTC for stuck solenoid B. I replaced the solenoids and no change. There's a TSB for this very issue to address a plunger in the valve body that gets stuck. I've entertained doing this TSB myself as paying to have it done would approach the cost of a new valve body (which is also an option). In order to address this "correctly" (from what I've read) would involve dropping the trans and updating the pump, replacing some other bits that regulate pressure or flow along with the valve body TSB and that's soundly in the territory to just replace the whole thing. So I am open to trying some basic things to mitigate it, as I won't entertain R&R'ing it for just this problem. In the mean time I run Torque on a tablet as I drive, and I can clear codes underway when it happens (maybe 3 times all last year) but would like to reduce or eliminate that process if I can.

Mark B.
Albuquerque, NM

EyezOpen · 02-10-2023, 12:44 PM

Now that's quite a project. Perhaps you might do a complete fluid flush including the converter. Open up the old filter and closely inspect for metal shavings...the bottom of the pan at the same time. Particles or contamination generally tell quite a story on a transmissions life.

catmandoo62 · 02-17-2023, 10:22 AM

that temp of 230 seems really high for long trans life.i saw a chart one time about trans temps and life expectancy,can't seem to find it right now but up over 210 or so life went down drastically.

donr103 · 02-17-2023, 06:52 PM

I can see your reasons for concern.. you got a point ... I can't predict tomorrow.. but one thing I would try.. is adding another transmission cooler and putting a fan on the one you got.. check derale.com.. .. if it does not have one.. you could also try to reduce weight.. or baby it.. that could get you extra time.. also keep fresh oil in it.. up inspection of the pan and filter..

If you have a flat and safe place to work on rv.. you would be surprised at how few bolts holed in trans.. you could save a lot if you just call in a few favors and do it with some friends and exchange complete unit ..
Good luck and keep us posted