TURBO 400 TRANSMISSION running temperature

[kartvines]

Question, finally got my motor home running to a point I could give it a hour test drive and everything seem to run much better but while watching the transmission gage temperature raised to 220 I got to wondering what the safe running temperature of this transmission ?

My motor home is a 83 Pace arrow with the stock 454 engine with banks exhaust, it that matters

[Wallaby Dan]

If memory serves, not over 190. You may get away with 200 if synthetic oils. Not for all day but if climbing up hill it could go to 220 but that is the highest for sure. anything higher and its cooking the trans. Need to pull over and let it cool for a bit.

[pcurt23]

I spent 20 years at the GM WillowRun Plant where the Hydra-Matic thm 400 was manufactured as a manufacturing engineer. I do not remember the specs but it seems that 220 is in the ball park. Pressure checks were more relevant than temperature checks. But, I worked on manufacturing of parts and not design. Here is a reference for the military version of the 400thm.

http://trucks125ton.tpub.com/TM-9-23...0579760979.htm

[George Schweikle]

My 454 gas Safari Trek runs about 190 (or less) transmission temp when towing a car trailer, but I added a second tranny cooler. 220 degrees when not towing seems too hot.

And, I used to live 15 miles from Willow Run.

Quote:

Originally Posted by pcurt23 I spent 20 years at the GM WillowRun Plant where the Hydra-Matic thm 400 was manufactured as a manufacturing engineer. I do not remember the specs but it seems that 220 is in the ball park. Pressure checks were more relevant than temperature checks. But, I worked on manufacturing of parts and not design. Here is a reference for the military version of the 400thm. TRANSMISSION OIL PRESSURE TESTS (3l80)

[kartvines]

Thanks for the feedback, my gage is hard to read being it is by the parking brake, and I do have a transmission cooler. So I guess I will have to try and read it better to get a clearer reading, I hate having to look down and to my left to get the reading. Most was uphill not pulling anything.

[pcurt23]

Here is a little more info on fluids. If the fluid is pink it means that it has not over heated.
Automatic Transmission Fluid

[Topflite51]

220 is TOO hot under normal conditions, I suspect bad sensor or bad gauge (or misread).

[kartvines]

The fluid is indeed pink with no odor and it did spread quickly so I must assume that I was not reading the gage correctly to it's location, after closer review it looks as if it was instead reading 200 max the number are so close once it passes the 180 mark it is hard to read unless I get out and look though the open door. the highest reading on the gage is 250 and it wasn't quite 3/4 over to the right side so in my opinion it would be all but impossible to know where the 190 is except somewhere between the 180 mark and the 200 mark, being it is not listed on that gage.

So I hope it is running the correct temperature, I had no problem with the trans during the operation of my motor-home, but was merely concerned based only only the gage.