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Stock Trans... Too Hot?

Chadgervais

Chadgervais

Former GP Owner
Greetings

I was just wondering if these temperatures are normal. I have never seen my "Hot Trans" light come on, but according to the DIC, i have seen temps that concern me.

On the highway, just cruising the trans temp hovers between 165 and 180, that seems normal. In city traffic with constant stop and go driving, ive seen it as high as 213.

On one day in particular, i was driving for about 7 hours, i was headed up the north shore of Massachusetts in heavy traffic. My trans starting slamming into gear, i checked my DIC and i was up to 228 degrees. I was still 4 hours from home so i hopped on the highway instead of taking route 1 all the way back to Bangor. I reached the rest area in Kennebunk ME, my trans had cooled to 210 but was still shifting hard. I stopped for about an hour, got something to eat and watched traffic. I checked my fluid, still red, no burnt smell. When i got going again my trans was down to 167 and was shifting great. I got back to Bangor and my trans never went above 186.

Are these temps normal? At what temperature does the hot trans light come on?

Thanks
 


160-180 is very normal.

Figure your coolant temp is around 200, so havibng the trans in traffic run at 200-215, it not un-common.

But if your seeing 215+ on a daily basis, then thats not so good for it.
 
That's about where my transmission was going in the summer, like you said once you start to sit in traffic or go up a mountain it can start to climb and I was seeing 210 at times.

I changed from stock Dex III fluid to dex IV and drove it that way for a few weeks and it seemed temps generally got 5-10 degrees cooler

Since I got my Overkill Tune though, I havnt see it go over 200 a single time... I dont think it's been over 190 in fact.

I know it has something to do with the cooling fans running full time at a certain coolant temp, but I think the operating parameters in the tune have something to do with it too.
 
Very normal.

160-180 as mentioned is ideal. Your radiator has a trans cooler built into it. This means the coolant is cooling the trans fluid. When you were sitting in traffic with that 195F thermostat in the cooling system and the fans that are programmed to come on around 212-218 on low speed. It's extremely normal to see those temps. Likely the slamming was a fault that was seen and the trans was pushing P1811 Max adapt shift. Aka full pressure shifts.

When you turn off the car and restart, that resets the codes.
 
Thanks guys. Now that the mornings are getting colder and im using the heat every day, the whole system is running cooler. On the highway even after a couple hours, my coolant will still fluctuate between 185 and 192 as opposed to those sweltering summer days when i couldnt get it to stay below 200. I also, without knowing it, had a bad radiator cap.

Replacing the cap caused the system to properly pressurize, which caused my elbows to fail. My transmission is happier now too, 167 on the highway and I havent seen it over 195 in town for a while
 


ive only seen my temps that high once, it was on the way home from the dealer on 110 degree day. normally 175-190. between work and home im only getting to a top of 150ish. i had bought a trans cooler but i believe the high temps this summer is what caused my car to be so hot.
 
im guessing you just have the base grand prix and a temp that high even in city traffic is high. I have a grand prix gxp and it was normal for it to run round 220 in city just because of the car...if you have that problem again when the temps outside get hot again just install a trans cooler...i have two and it makes a huge difference.
 
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