Tourque Converter Temps

90sc35thann

Registered User
My car is running well however I was under my car the other night using my infra-red temperature gun and I was taking temp readings right after driving the car. My tranny pan temp was 120 degrees F. No problem there, but my tourque converter was 200 degree F. I am using a non-locking converter and wanted to know if this was a normal temp for a converter of this type? Everythihng is running fine but I was shocked at the difference in temperature from pan to converter. Any feedback appreciated.
 
hmm

I dont know what the running temp of the tourque converter should be. But i do know that the 3.8L Supercharged engines are supposed to have electric lockup TCs. Just like turbo Buicks and other power aspirated cars, they dont produce constant torque unless your laying into the throttle, thus it is common for a non electric lockup to drop in and out of OD and 3rd. This creates a -thump- when driving at certian speeds, then a high rev them another -thump-. This can potentially really tear up an AOD. My friend had a modifed T-Type (Buick 3.8L Turbo non-IC) that someone dumped a Turbo-350 trans into. It suffored from the lack of torque problem at cruising speed, and eventually the dumping in and out of gear sheared off the bolts for the flexplate. When we dropped the orignal back in (came with the car when purchased) the problem whent away, cause it was adjusted for the fluxuations in torque. So In summary, if your expirenceing the randomly droping out of gear, its likely producing excess friction, and excess friction = Heat, excess heat = excess friction, excess fricton = even more heat. So Possibly thats the reason the TC is warmer than the rest of tranny. But this is only a shot in the dark, cause i dont know the running specs for the AOD in an SC. My SC locks up in OD at 45 and will remian there untill it slows to 40 (when crusing). ...Good luck
 
The torque converter used in the early model SCs with AOD transmission are not electric locking type converters. They use a dual shaft system and the converter has two sets of splines.

The outer shaft is for 1st and 2nd gear and attaches to the impeller splines of the torque converter. The inner shaft for 3rd and OD attaches to a matching female spline that is welded to the body of the torque converter.

That means 1st and 2nd are never locked and 3rd and OD are always locked. Aftermarket non-locking converters either have a solid 1 pc. shaft or as in the case of Lentech attach both sets of splines to the impeller to prevent locking in any gear.

I'm not sure what converter temps are supposed to be, but 200 degrees doesn't really sound that high since that's where most of the transmission heat is generated. The friction from the impeller shearing the transmission fluid is what makes it get hot. Non-locking or high stall converters generate more heat for the same reason and require additional cooling. Just make sure to keep pan temps below 200 and it will be fine.

David
 
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