Overheating tranny only in park

[13CamaroSSL99]

I have a 13 ss2 Camaro with l99 and a 6 speed auto. i recently purchased this car from my local gm dealership about 6 days ago . I have an aftermarket warranty due to the dyno tune and custom dual exhaust. I noticed however the tranny overheats only in park. I've already put a Hayden rapid cool tranny cooler and it only helps it cool down faster in drive. i checked my coolant level this morning and it was scary lo. So i flushed the radiator this morning and put new prestone dex cool in it. i also believe there is a 170 tstat installed in it also. When in park my coolant level shoots up to about 205-220. Ive already looked at my radiator fans and they both spin any suggestions?

[NOT A 45]

Originally Posted by 13CamaroSSL99

I have a 13 ss2 Camaro with l99 and a 6 speed auto. i recently purchased this car from my local gm dealership about 6 days ago . I have an aftermarket warranty due to the dyno tune and custom dual exhaust. I noticed however the tranny overheats only in park. I've already put a Hayden rapid cool tranny cooler and it only helps it cool down faster in drive. i checked my coolant level this morning and it was scary lo. So i flushed the radiator this morning and put new prestone dex cool in it. i also believe there is a 170 tstat installed in it also. When in park my coolant level shoots up to about 205-220. Ive already looked at my radiator fans and they both spin any suggestions?

Turn the a/c on, do your fans come on? If so eliminate that as a problem. The ecm will not turn the fans on until approx 227-228 degrees. Fix the coolant leak....that shit doesn't evaporate! Once you've established the cooling system is fine and operating normally, compare your trans temp to your coolant temp. They should be very close to the same at operating temperature especially in park! If not, I would suspect a bad thermistor in the transmission control module. Not un heard of, I've seen it before.

[13CamaroSSL99]

Originally Posted by NOT A 45

Turn the a/c on, do your fans come on? If so eliminate that as a problem. The ecm will not turn the fans on until approx 227-228 degrees. Fix the coolant leak....that shit doesn't evaporate! Once you've established the cooling system is fine and operating normally, compare your trans temp to your coolant temp. They should be very close to the same at operating temperature especially in park! If not, I would suspect a bad thermistor in the transmission control module. Not un heard of, I've seen it before.

Both fans turn on, there is no visible leaks, could it be my radiator going bad?

[gtstorey]

At least a decent chance the fans have been adjusted to come on at a lower temperature since it has been tuned.

Does the transmission cooler still route through the radiator? If not, how big is the transmission cooler? Does it have it's own fan? If it doesn't have it's own fan, how is the cooler mounted? It might not have much air pulled through by the car's fan when sitting.

[NOT A 45]

Originally Posted by 13CamaroSSL99

Both fans turn on, there is no visible leaks, could it be my radiator going bad?

Your cooler is located inside the bottom tank of the radiator. Your engines coolant is what cools the transmission fluid, not direct air like you would assume. So transmission temp effects coolant temp and visa versa. I have seen coolers clog and become restricted usually due to converter failure but the symptoms are overheating while driving. You have just the opposite. Without having the car in front of me, I'd be willing to bet on a bad temp sensor in the tcm which is located inside the transmission.

[13CamaroSSL99]

Originally Posted by gtstorey

At least a decent chance the fans have been adjusted to come on at a lower temperature since it has been tuned.

Does the transmission cooler still route through the radiator? If not, how big is the transmission cooler? Does it have it's own fan? If it doesn't have it's own fan, how is the cooler mounted? It might not have much air pulled through by the car's fan when sitting.

Yes i ran it through the tranny cooler is an 11x11

[13CamaroSSL99]

Originally Posted by NOT A 45

Your cooler is located inside the bottom tank of the radiator. Your engines coolant is what cools the transmission fluid, not direct air like you would assume. So transmission temp effects coolant temp and visa versa. I have seen coolers clog and become restricted usually due to converter failure but the symptoms are overheating while driving. You have just the opposite. Without having the car in front of me, I'd be willing to bet on a bad temp sensor in the tcm which is located inside the transmission.

Now it gets weird i flushed the coolant out this morning and now only starts to get hot in the 15-30 mph range and coolant is only getting to about an 208-215 avg with stop and go driving in city. when parked now coolant stays at about 198 and the tranny drops down to about 170. and engine temp 215-220. I honestly have no clue what to next. the tranny isnt slipping and its running on amsoil racing fluid for tranny and prestone dex cool for radiator

[NOT A 45]

Originally Posted by 13CamaroSSL99

Now it gets weird i flushed the coolant out this morning and now only starts to get hot in the 15-30 mph range and coolant is only getting to about an 208-215 avg with stop and go driving in city. when parked now coolant stays at about 198 and the tranny drops down to about 170. and engine temp 215-220. I honestly have no clue what to next. the tranny isnt slipping and its running on amsoil racing fluid for tranny and prestone dex cool for radiator

When your in stop and go, what is the trans temp?

[gtstorey]

"engine temp 215-220"

Engine oil temp?

I'm not sure if there is anything wrong with those numbers especially if the parked is with ac on and driving ac is off. If the Hayden is after the radiator that would account for the transmission temp being lower than coolant.

Of course our temps going from upper 90's through yesterday to mid 80's today may also have something to do with it.

[NOT A 45]

Originally Posted by gtstorey

"engine temp 215-220"

Engine oil temp?

I'm not sure if there is anything wrong with those numbers especially if the parked is with ac on and driving ac is off. If the Hayden is after the radiator that would account for the transmission temp being lower than coolant.

Of course our temps going from upper 90's through yesterday to mid 80's today may also have something to do with it.

I'm wondering if he has any problem at all. I wouldn't be concerned until the trans temp approaches 270 or so. Here again, if he has a aftermarket converter I would expect higher than normal temps running 30-35 mph just from the slippage.

[PaulsSS]

Maybe the programming for trans is off and its not locking up etc when it should be.

[Rock-It Man]

When your cooling system is not holding pressure, the boiling point goes up...physics. You can keep adding coolant all you want, but until the leak is fixed, your system will continue boiling off coolant and run hot.

When pressurized, the system will stabilize around 190 degrees. The thermostat will open at 170, but that doesn't change the steady state temp at idle.

[redrum_maro]

Originally Posted by Rock-It Man

When your cooling system is not holding pressure, the boiling point goes up...physics.

Correction, it is "lowering the pressure will lower the boiling point."

[13CamaroSSL99]

Originally Posted by NOT A 45

When your in stop and go, what is the trans temp?

My stop and go temp gets up to about 190-210 i might also mention ts been over a hundred degrrees here yesterday was 110