Transmission Temperature

[TCDiesel]

Not Much data on that,but most claim 400+F and I seen as high as 800F. Running 250* consistently over time will accelerate wear. The big diff claimed By Chrysler form 3 to 4 is 4 boil point and life,much higher and longer,statements made by Chrysler keep the temps low and ATF+4 is good for life. life of what? you or the vehicle. heeeeeeeeee

 

[Matt400]

Matt400 I think may know the value

I know 180 ohm works on the 03's but they changed the sending unit and software on the 04's and newer so the 180 doesn't work on those for that reason. Seems to me the 04's needed a 700 ohm resistor but not sure on that and can't say for the 05's



What I later found was the fan will ramp up on its own as you put fuel to the motor, coolant temps rise and result in the fan commanded on before transmission temperatures are an issue. I don't see how you could get trans fluid hot enough to need the fan before engine coolant temp will need it. I believe it's this reason the engineers never tied the transmission temp sensor to fan operation because the engine will have already turned it on due to coolant temps.



The manual fan switch on my 03 was a neat idea but I later found I never used it.

 

[TCDiesel]

I use it all the Time, in the winter months, (B/C I have the early 03 the C/C ramp is not available) after a few minutes at idle I turn it on,the fan cycles on an off (drag on motor shortens the time to warm up) engage the Exhaust brake in 5 minutes I have heat. In the summer I use it in conjunction with A/C and long Idle times or using it with the elec/hydraulic lift trailer(s) we have. Also when climbing the Rockies I flip it on before the coolant temp start to rise. Yep I been in some back country that I will never do twice.....

 

[Matt400]

Well there you go... glad to see it can be useful.

 

[Yo Hoot]

Check this out. .
http://www.autoshop101.com/forms/AT06.pdf

 

[Matt400]

Good info but possibly dated as it calls for Dex II fluids on newer Toyota's.

Now days they are using ATF WS and ATF T-IV depending on model. The last paragraph is interesting relating fluid temps to trans life.

Main thing is to install and use a temp gauge to keep temps in check.

 

[Yo Hoot]

On a hot day no load... my trans at the hot line today was hovering around 220 degrees at a traffic light stopped. The traffic light was a longer one. The temp didn't rise or fall. When I get moving and it locks up the temp drops to 190 in about 30 seconds. Cruising the highway I'm 160. I read in my latest TDR publication that Chrysler says it can reach 230 at which point you should take action to reduce the heat. That is based on the newer models that have a trans temp gauge. I'm willing to bet Chrysler knows it easily runs 220 when fluid coupling.

Does anybody know where Chrysler gets it temp reading from on the newer trucks that the trans temp gauge gets?