What I have: 1996 Fleetwood Southwind 35LS, 460EFI, E4OD, Banks headers, Transcommand, US Gears Dual Range (under/direct), Dana series 80 5.13, trans temp gage, 96k miles, 19,800 Lbs fully loaded (includes all passengers).The E4OD was rebuilt a couple years ago by the previous owner, he burned it up while towing his car on a car hauler. I am sure he was over the 23,500 Lbs max GCVW for this coach. Also, I doubt he understood how to use the auxiliary transmission. He had the E4OD rebuilt by a shop out east and they also replaced the radiator, added the trans temp gage, and possibly installed the auxiliary trans cooler. This was about 6k miles ago. When I run on flat ground the gage reads at the top of the normal range (about 200 F). When I ascend mountains (plenty around Las Vegas where we live) it is in the 220 to 240 range. We don't tow a car and I can ascend the mountains easily enough by locking out OD and climbing in 3rd (low range on the US Gears when they are really steep) with only a few down shifts to 2nd. I can maintain 40 to 50 MPH at using this method but at the above mentioned temp.The charts I have read suggest that I'll only get 20k - 40k out of the transmission at these temps. What is the best way to get them down? Can I mount a DC fan in the front of the cooler with a switch on the dash? Should I install a larger cooler (I have gobs of room)? Or will slowing down on the ascents solve the issue? I am sure that this summer's 100F+ temps will compound the problem.If I can figure out how to upload pics I will post them. Thanks!

Add a larger transmission cooler with an electric fan.

Where is the trans cooler? Is it in warm or ambient temp flow? Moving the cooler and adding a fan would be a possible solution.

It is located where it gets ambient air from the front grille in front of the condenser. There is about 18 inches between the cooler and the grille. Its only about 12 inches by 9 inches in size. Would moving it closer to the grille help?

colonelcorto wrote:It is located where it gets ambient air from the front grille in front of the condenser. There is about 18 inches between the cooler and the grille. Its only about 12 inches by 9 inches in size. Would moving it closer to the grille help?When you go slow, during a climb, there may not be enough air movement to provide sufficient cooling. I would replace that cooler with a larger one and add an electric cooling fan that you can switch on manually if the temps start to climb. Get one rated for 30,000 pounds GVWR.

Does the temp gage read correctly?

Hot Transmission, what can I do? | Good Sam Community

Chum_lee
Explorer
Apr 27, 2017
What does the fluid LOOK and SMELL like compared to new fluid? If its off color or has a burnt smell to it, clearly, after 6000 miles it is getting too hot. Remember that the transmission fluid temperature gauge only tells the AVERAGE temperature of the fluid at the location of the sensor. When the fluid is under shear stresses in the planetary gear sets, bushings, and clutch packs, portions of the fluid may get much hotter than what the gauge says but only momentarily before it mixes with other cooler fluid. That is why the fluid is circulated (mixed) constantly. Generally its the temporary elevation of the fluid temperature under stress that kills it, not the average temperature in the lines or pan.

A quick cheap fluid test is to place several drops of fluid on the back of a clean white business card. If the fluid disperses evenly into the paper, its a good sign. (not a guarantee) If you see rings, blots of soot, or particulate debris, the fluid is toast.

In my younger shop days I seem to remember the fluid temperature charts referencing suggested fluid life rather than transmission life.

Chum lee
rgatijnet1
Explorer III
Apr 26, 2017
The main thing you need to find out is where the fluid temp sensor is located. The hottest place for your fluid is at the output from the torque converter. One of the cooler places is in one of the transmission lines coming from the cooler or in the pan itself.
Depending on where the temperature is being taken, your fluid temperature coming out of the torque converter could be much higher than the 200 degrees that you are seeing.
Redwoodcamper
Explorer
Apr 26, 2017
Those temps arnt that high. The chart you see is how long the tranny fluid will last at those temps. Not the tranny itself. Changing tranny fluid ever 20-40k miles isn't a big deal. Those temps won't necessarily do any damage to the tranny. It is slightly higher than preferred, but I wouldn't sweat it.
colonelcorto
Explorer
Apr 26, 2017
time2roll wrote:
colonelcorto wrote:
The charts I have read suggest that I'll only get 20k - 40k out of the transmission at these temps. What is the best way to get them down?
Those charts are generally from the '60s and relate to old fluid not the new synthetics or to the transmission itself.

Next service switch to synthetic fluid as you should find something compatible. And by all means add the largest stacked plate auxiliary cooler you can.

Can you tell if the torque converter is locked up at those speeds and temperature?

Ah, funny you should ask about TC lockup. I am not entirely sure how one should normally operate. In automatic cars I have owned in the past this has been noticeable as almost a small gear shift (RPMs drop by a few hundred. This thing has me confused. The E4OD has only 4 gears but I count what seems like 5 or 6 shifts, especially at lower speeds. Is this the TC locking up and dropping RPMs? I should note that there is a transcommand installed, I have been meaning to verify that all of the wiring is still good but have not done so yet.
colonelcorto
Explorer
Apr 26, 2017
crasster wrote:
Some of these suggestions are easier said than done. The fan itself couldn't be just an electric fan, must be 12v and have a thermostat to cut on. Also should be durable (auto grade) for rain/weather, etc. I'd suggest just adding the cooler first to open venting and then go from there if needed.

I agree. The MH already has an oil cooler intsalled, I count 30 plates in it. Moving it closer to the grille will involve extending or replacing the ATF lines. I am leaning toward adding a fan to the existing cooler and then relocating if that doesn't help.
colonelcorto
Explorer
Apr 26, 2017
CharlesinGA wrote:
All of the temp charts on the internet show fluid breakdown beginning by 220F or so and the life getting very short above that.

I would get a LARGE transmission cooler with a built in fan that operates on a thermostatic switch, also built into it. There are a number on the market.

What brand gauge is it? where is the temp sensor mounted? Do you have a deep aluminum pan installed to add additional fluid quantity to the transmission so it will run cooler, plus the cooling the aluminum pan offers.

Chales

The brand is B&M or something, it's a type I have seen in many applications. Not sure where the sensor is mounted, the wire disappears behind the dash and I assume goes toward the transmission. The pan is painted blue with a bit of surface rust at one edge, I don't think it is aluminum. Personally, I would feel better with a steel pan... it is too dangerous to swerve this MH around debris in a travel lane. I'd hate to see how an aluminum pan does vs. lumber, furniture, or who knows what else falls in the road.
colonelcorto
Explorer
Apr 26, 2017
Heisenberg wrote:
Does the temp gage read correctly?

I can't be certain but it was "professionally" installed by the shop who did the rebuild.
femailyetti
Explorer
Apr 26, 2017
Check out page 31 on fixing a 1986 holiday rambler for a product that may be what you are looking for.
time2roll
Nomad
Apr 25, 2017
colonelcorto wrote:
The charts I have read suggest that I'll only get 20k - 40k out of the transmission at these temps. What is the best way to get them down?
Those charts are generally from the '60s and relate to old fluid not the new synthetics or to the transmission itself.

Next service switch to synthetic fluid as you should find something compatible. And by all means add the largest stacked plate auxiliary cooler you can.

Can you tell if the torque converter is locked up at those speeds and temperature?
Gjac
Explorer III
Apr 25, 2017
When you say the temp gauge reads 220 -240 is that your trans temp gauge or the engine temp gauge? If that is your trans temp what is your engine temp reading? Usually the engine temp is higher that the trans reading. If that is the case with a rebuilt trans and new radiator I would suspect that the gauge is off. You can verify your readings with an IR gun to see if your gauge is right. You can take readings by your sensor then take readings at your oil cooler top and bottom to see if it is cooling properly. You can also take reading of your radiator from top to bottom to see if it is cooling correctly, you should see a temp of at least 30 degrees cooler at the exit than from the inlet where it comes out off the thermostat. Fixing heat problems on these old big block engines can be challenging.