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transmission temp too high?

L

Linebacker

New member
hey

2005 Grand prix gtp comp-g
157000 KMS

So last winter i had a full rebuild done on my transmission. It did not go smoothly and the shop was a bi*ch to deal with, you can read about it on previous threads i started if you wish. Anyways now something new has popped up and wanted to know if its actually a problem or not.


Last summer my transmission would sit around 200-206F after long amounts of city driving, alot of stop and go and rush hour pretty much. Highways it was usually around 194F.


Today i notice after about 30 min of driving in rush hour with the outside temp at 74F my transmission temp was 222. Alot higher than it ever got last summer, so is this too high? and is there anything small i could do to help the problem? like changing the transmission fluid to a quality brand synthetic? because i am sure the shop used some cheap house brand dino crap.
 


Well u could do a tranny pan drop and filter change but that won't help temps. You could install an extra cooler to the front of ur transmission. If u keep an eye at my my ride thread this weekend I will be installing my new tranny cooler. I'll show how and all so u could as well
 
well any ideas on why its so much higher after a rebuild? like its all the same parts that came with it stock, only thing different is they added a shift kit. and is 220 a dangerous temp to run at?
 
marines542 said:
Well u could do a tranny pan drop and filter change but that won't help temps. You could install an extra cooler to the front of ur transmission. If u keep an eye at my my ride thread this weekend I will be installing my new tranny cooler. I'll show how and all so u could as well
Click to expand...

if you do a cooler install with a walkthrough by the way that would be great.
 
Just because the trans was rebuilt doesn't mean it can't get hot. Trans temps are affected by many outside factors. Stop and go traffic will get a trans hotter faster. Install an aftermarket cooler.
 


Also check my my ride thread out..links in my SIG and u can see what my new cooler looks like. It was a little more expensive but in my mind its worth it. Keep in mind I have the gxp with 5.3 not 3.8 so the gxp runs stock temps of 210°F so a cooler is almost required
 
GTPpower said:
A colder thermostat will be a cheap/easy way for you to lower your trans temps.
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To my understanding that won't do much if anything unless u tune for it. Because the fans won't kick on earlier so cooling won't be affected to much
 
The fans are only used when the radiator isn't able to keep enough airflow through it to keep it under temps. As long as you are somewhat moving, it will keep it cooler than a 195* t-stat will.
 
People running a 180 thermostat without the fans tuned are still seeing 200+ coolant temps. Besides 180 thermostat is a waste even if you do have the fans tuned.
 


I've been running a 180° t-stat, and It has only made it to 200° twice in the past 3 months. It normally runs at 190-195°F city traffic. Whereas before with the stock t-stat, it would run at 198+

When I'm on the highway (rare) I see 185-190°.
 
stealthee said:
Just because the trans was rebuilt doesn't mean it can't get hot. Trans temps are affected by many outside factors. Stop and go traffic will get a trans hotter faster. Install an aftermarket cooler.
Click to expand...

I am not surprised by the fact it gets hot, i am surprised that after a full rebuild and flush that it gets alot hotter than the original trans did, i thought it would be the same, Last summer i once did city driving for 8 hours in stop and go traffic and it did not once go past 210, now after 30 min i am getting 222, thats what puzzling to me.

Any ideas why im getting a spike now?

And is 222 really that big of a deal to begin with?
 
222° isn't a "big deal" so to say, but it doesn't need to get this hot. Nothing gets better as the temps get higher than 200°. If I were you, I'd just install an aftermarket trans cooler in series with your stock one so the temps stay at or below 200°.

Also remember that your transmission is cooled by your engine temperature coolant. If your engine was always running at 200 last year, and your trans ran at 210, but this time your engine was running at 210, and your trans was running at 222, that would be normal.
 
GTPpower said:
Uhhh....if you are running a 180* t-stat and are seeing 200+* coolant temps, you have something wrong.
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200 is where temps normally run. 195 is just where the stock thermostat opens. With a 180 thermostat, sure it opens at 180, but the temp is still going to climb until the fans kick on, hence you will still see 200+.
 


^^^ Hmm.... I have a 180* stat AND tuned for it. Even in stop and go traffic or pulling my mountain behind a slow paranoid driver my temp gauge has never gotten above quarter way on my gauge so IMO and based on my experience with my car it's working properly and keeping my motor around 180 - 190 degrees. If mine hits 200 or 210 I'd be concerned after what I've done to keep it cool.

NOW if you drop your tstat temp and NOT tuned for it then you will have more erratic temperature movement according to your gauge (in stop and go traffic). If you are in stop and go traffic, your coolant temp can get to 200* because while your car is not moving your fans will not start to circulate air over your radiator until you have hit your factory temp settings. By this point, your motor will probaly be running hotter because your stat will be open more frequently not allowing your coolant to sit and absorb the heat from the motor as it's suppose to... It is ideal to have your stat and fans working hand in hand.

Your trans pump is constantly working so really your trans fluid does not "sit" in your radiator and cool as your coolant does. When I have my trans built, I (personally) will run an external trans cooler large enough to bypass my radiator one. I will also have an electric fan attached to it on the front pushing air through.

This is just my $.02 and maybe wrong, but seems legit.. LOL
 
stealthee said:
200 is where temps normally run. 195 is just where the stock thermostat opens. With a 180 thermostat, sure it opens at 180, but the temp is still going to climb until the fans kick on, hence you will still see 200+.
Click to expand...

Yeah, if you are sitting in traffic. Any other time, it SHOULDN't get that hot. Unless you have other issues.
 
dbextreme said:
^^^ Hmm.... I have a 180* stat AND tuned for it. Even in stop and go traffic or pulling my mountain behind a slow paranoid driver my temp gauge has never gotten above quarter way on my gauge so IMO and based on my experience with my car it's working properly and keeping my motor around 180 - 190 degrees. If mine hits 200 or 210 I'd be concerned after what I've done to keep it cool.

NOW if you drop your tstat temp and NOT tuned for it then you will have more erratic temperature movement according to your gauge (in stop and go traffic). If you are in stop and go traffic, your coolant temp can get to 200* because while your car is not moving your fans will not start to circulate air over your radiator until you have hit your factory temp settings. By this point, your motor will probaly be running hotter because your stat will be open more frequently not allowing your coolant to sit and absorb the heat from the motor as it's suppose to... It is ideal to have your stat and fans working hand in hand.

Your trans pump is constantly working so really your trans fluid does not "sit" in your radiator and cool as your coolant does. When I have my trans built, I (personally) will run an external trans cooler large enough to bypass my radiator one. I will also have an electric fan attached to it on the front pushing air through.

This is just my $.02 and maybe wrong, but seems legit.. LOL
Click to expand...

The actual reason the transmission oil is routed through the radiator, is to help warm it up on cold days. As you said, the radiator doesn't work very well to help cool it off, once it's above the T-stat rating.
 
I want to install an aux tranny cooler as well, the one from TEP in line with the stock one, but I'm not sure what to do in the winter when it's like 10 degrees out. I don't want my tranny to take ages to get up to operating temps.

I see ZZP sells a tranny pan with cooling fins, I'd just get that if it wasn't so expensive.
 
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