AT transmission overheating while offroading- Mostly offroading hills (1 Viewer)

[Hazmatt911]

i've tried searching but couldn't find my exact issues i recently accured a 1996 LX450 with automatic A343F transmission, on 35s with 4.56 gears. It has an upgrade transmission cooler installed by the previous owner which i think is a EMPI A343F cooler. When on the highway AT temps are normal around 155-188 but when offroading in WV few weekends ago I looked down at the transmission temp gauge and seen it was 220, so let it cool for a bit an tried touching cooler but it felt like room temperture like the trans oil wasnt circulating? sitting even for 20 mintues didnt cool it down only driving down some hills getting airflow did the trick.

This was the second overlanding day were i had the AT issues, with the airtemp around 82-84 no issues at all on the first day but the first day was mostly flat alot more water\rain on the trails. wanted to hear your thoughts an opinion.

 

[Malleus]

What transmission temperature gauge? The 80 series doesn't have one; it only has an idiot light.

The maximum range of the ATF temperature sensor is 230°F. If the sensor is has been exposed to greater temperature or is otherwise malfunctioning, it may not provide the correct temperature indication. I'd check the sensor:

It's highly unlikely that your cooling loop isn't working, however, you can check it by removing the outflow hose and routing it into a container, and then starting the engine. The transmission oil pump will send fluid through the loop as soon as the engine starts rotating. I wouldn't advise running it this way after you have verified the cooling loop is full and flowing; you'll run low on fluid quickly.

If no fluid flows out of the outflow hose immediately, you have a problem. I'd start at the transmission cooler output line and work my way to the cooler, doing exactly what I described before to find out where the flow restriction is; however, as I said, it's unlikely this is the problem because the fluid flows when the pump is turning, which is whenever the engine is turning. Unless your torque converter is futzed.

 

[Malleus]

The temperature sensor is in the cooler line, at the front of the transmission.

 

[Hazmatt911]

Thanks Malleus, the previous owner installed a aftermarket transmission gauge and its ran to a sensor on the transmission. I did check the supply line to the cooler and that is supplying ATF fluid to the cooler but i should also check the return line to make sure its looping back to the trans. I did see the form posts about the Torque converter i'll try diving into that thread more to see the symptoms of that.

 

[Malleus]

There's really only one way for you to check the operation of the torque converter: put the truck on the road at 53+mph and watch the tach. If it drops, the converter is working. If not, it's either the solenoid or the converter, but at crawling speeds it's not doing anything, so I can't see that being your problem.

I'd pull the sensor and test that, after verifying the return line flow, before I did anything else.

 

[Malleus]

Good grief! That's a serious cooler.

 

[efjayatee]

I have this kit:

Post in thread 'Derale Transmission Oil Cooler with Bypass' Derale Transmission Oil Cooler with Bypass - https://forum.ih8mud.com/threads/derale-transmission-oil-cooler-with-bypass.1256291/post-15154869

Fan kicks in when temp reaches 180 and turns off when cools down to 165

 

[Hazmatt911]

yea that is a crazy cooler with the fan but the cooler i have is just the 24 plate fanless model

48 Plate Transmission Cooler, 6 1/2" x 11" x 1 1/2", 15,000 BTU, 19,000 GVW Rating - EMPI

empius.com

 

[efjayatee]

All you need is a bracket to mount a pusher/puller fan but depends where yours is located.....(front of grill?) Mine is where the spare tire used to be.
Mounts manual ON/OFF switch asduming you have a tranny temp gauge.