Thread: Transmission running at 210*-240*!!!

i see 209 at 100degree days, not 240 though

Ill check mine tomorrow during the day. pretty sure mine are over 200

I don't think mine have exceeded 180 F.

Originally Posted by klogan

My 2008 gp's trans runs at 210-240* in hot weather! This can't be normal, can it?

Should probably never see more than 225*. Low on trans fluid? Is it bad? when was your last transmission flush with filter change?

I was gonna say I get up to about 215ish on the really hot muggy days but never over

x2 on the coolant question

A rule of thumb has been that tranny fluid starts to break down at 220°F. So I always like to see mine below that. If you are running the newer Dexron VI fluid, you probably have a little more room to breathe. But not much. IMO, that's too hot.

Check to see what the coolant temp is at that point. And if possible, add a tranny cooler.

Originally Posted by Zef_66

add a tranny cooler.

This is not a solution to the problem.

Originally Posted by SlowNA06

This is not a solution to the problem.

Why not? If his tranny is running hot because he is in 100° heat and sitting in traffic with the AC on, then it is a perfect solution to the problem.

If he has a different issue that his tranny fluid is getting so hot, then no, it is not a solution. But it will probably help.

I don't see a downside to installing a tranny cooler (other than the ZZP professed crap about a tranny line coming loose)

i was driving on I 70 in colorado through the mountians, and i saw 246* trans temp. coolant was running a little hot, but not bad. everything cooled off once i started going downhill. Once i stopped i checked all the fluids and everything was good. Ive heard that around 260* is when bad things start to happen

Originally Posted by Lenny

Ive heard that around 260* is when bad things start to happen

Probably not the best source, but the best I could find in the minute of searching. Link.

Automatic Transmission Fluid Temperature
Automatic transmission fluid (ATF) has a life of about 100,000 miles at 175oF. At high temperatures, it oxidizes, turns from red to brown and exhibits a burnt smell. In addition to reducing the oil’s lubricating quality, high temperature produces a varnish on internal parts interfering with the operation of the transmission. Above 250oF., rubber seals harden, leading to pressure loss and leaks. Also, the transmission can slip. In the worst cases,
clutches fail and costly repairs result. ATF manufacturers suggest that for every 20oF. increase in operating temperature above 175oF., the life of the fluid is cut in half. Hence at 195oF., oil life will be about 50,000 miles. Above 240oF., it becomes nil.

Originally Posted by Zef_66

Probably not the best source

your right its not... im not saying its ok if you run all the time at those temps. i usually see 160* - 180* depending on the outside temp, and how im driving. but sometimes hot happends

I just checked mine I never see above 205

this maybe a dumb question, but how are you all checking the trans temp, is there a sensor and gauge combo, or through a scan of some sort?

Originally Posted by matt5112

latter is the only correct method.

and what type of scanner would that be?

i wouldn't mind have such info at hand down the road.

my gmc truck had a gauge for the trans temp and it was for sure nice to have when towing or snow plowing. as temps did vary a lot.

Thats how I scan!