Normal Diff temps, highway driving and racing

[mmakam2]

My 19 GT350 gets to 200F just cruising on the highway, is this normal? I believe my car has a diff cooler also..

I would imagine racing the car will get it even higher, what temps are others seeing?

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[JAJ]

My 19 GT350 gets to 200F just cruising on the highway, is this normal? I believe my car has a diff cooler also..

I would imagine racing the car will get it even higher, what temps are others seeing?

The cooler has a thermostat, and 200 isn't hot enough to kick it in, so for your climate, 200 is probably normal. I see about 170 on the highway in Washington State.

As for the track, the cooler pump kicks in and it works to keep the temp down - it settles at about 220 on mine, but others get hotter I understand - depends on the track and your driving style.

 

[honeybadger]

I saw 332* at Road Atlanta on the Hoosiers. IMHO, 220-240 sounds about right for R compound tires. But once you get to full racing slicks, it gets MUCH hotter.

 

[jpindustrie]

200 Is very much normal operating temp (street during summer climates), maybe up to 215-220 in the summer if im doing some highway pulls...

during the 100 degrees days on bear mountain runs (2nd/3rd gear 5k to redline) I would see temps of 225-235. Sustained track sessions on hot summer days I've seen it around 240-250; without the diff coolers I would expect the car to cook the oil in the rear no problem..

Ive seen 'oem'/factory oil start to do nasty things north of 300 degrees,.. those temps would require constant changes

 

[mmakam2]

great info thanks folks

 

[GT_Dave]

On hot days mine sees 190-195 degrees for highway driving, when I turn on the pump it will drop 25-30 degrees.

 

[mmakam2]

Is there anyway to reprogram the stock thermostat to open sooner?

 

[Niz55]

Little off topic, but my tranny always runs cooler than my diff. Is this normal?

 

[mmakam2]

Little off topic, but my tranny always runs cooler than my diff. Is this normal?

mine does the same.

 

[GT_Dave]

Little off topic, but my tranny always runs cooler than my diff. Is this normal?

That is because your differential is an electric pump that is controlled by a thermostat. The transmission cooler is mechanical pump in the trans and runs continuously.

 

[galaxy]

The transmission cooler is mechanical pump in the trans and runs continuously.

I think there's a caveat to this (albeit a very minor one)...like it only works when the clutch is out, or the car is actually moving, or something like that??

 

[JAJ]

I think there's a caveat to this (albeit a very minor one)...like it only works when the clutch is out, or the car is actually moving, or something like that??

Correct - the pump runs off the transmission input shaft, so if the shaft is stopped then the pump is stopped. If the vehicle is moving and it's in gear, the shaft is turning, and if the engine is running and the clutch pedal is up, then the shaft is turning. Needless to say, the pump runs pretty much all the time.

 

[CNFLCTD]

Forgive my naivety but there is a way to manually run the pump?

 

[honeybadger]

You could leave it in gear, put it on a lift and turn the tires by hand

 

[JAJ]

Forgive my naivety but there is a way to manually run the pump?

Most of us who want to run the pump "manually" just start the engine, put the trans in neutral and release the clutch. Or you can do it the way HB suggests, although you'll need two helpers - one to hold the clutch pedal down and the other to keep the other rear tire from turning.

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