Ok here is what all I had done 6 weeks ago. Tranny pulled and completely rebuilt, upgraded the clutch paks and installed more robust parts. Kept transgo shift kit and vette servo. Replaced the stock converter with a PI Vigilante 28-3000 stall. And finally installed a new SSPE adj. torque arm. All this done by a reputable mechanic, and he has done previous tranny work for me.

But what I got is a "rubbing" noise or some kind of resonant vibration right about 40mph, in 4th gear with TCC locked. And it is real loud when car is under a load, like going up a back road hill. Once I get above 45 it smooths out, and quiets down. Now this ONLY occurs with TCC locked, and in 4th gear. It locks in 3rd, but only for a few seconds. So I took it back to my mechanic, and took him for a drive, so he could listen. He didnt really think anything was wrong. Thought maybe a resonance coming from the exhaust, at that speed condition. Also said that since the SSPE torque arm is now connected to the crossmember, that maybe more sounds are getting transmitted up to the cockpit. And of course the exhaust pipe is real close to driveshaft and torque arm.

Now what else the mechanic said, was to change the TCC lockup to a higher speed, so that it wouldnt lock until I got to like 45mph. Since I do my own chips, that was easy to do. But I think that just masks the problem. Also I have read here that is best to lock the TCC, and keep it locked as much as possible.

One last thing, I think my engine is running a bit hotter with all this work done. I am def running more rpms, until I get to cruising speed. But I am still below 190deg. The converter runs cooler when TCC is locked, yes?

TIA!
Mike

 

The TC (thus the ATF too) will run quite a bit cooler once the TCC is locked since you remove alot of the slippage that causes the heat in the first place. But when its not locked that higher stall will cause some slightly higher running temps (both trans and engine) than it did with a stock stall due to the added slippage at low speed.


As for the noise, i would still be worried about something in the tranny. Its pretty unlikely that its resonance from the exhaust or whatever if it only makes the noise while the TCC is locked...

 

Thanks 84z, kind of what I thought with the higher stall TC, with things running a bit warmer. I do have the tranny cooler(stock) mounted in the radiator, and everything is working. Correct me if I am wrong, but is it a myth that the tranny cooler only works when the TCC is locked? Seems like that myth sticks in my mind for some reason. Maybe from the PROM boards. I just made a new chip with lock/unlock at 43/41 in 4th, so we'll see how that works.
As for the noise, it does worry me, but it is hard to describe. Only happens when TCC locks in 4th right around 40-42. If I am just accelerating normal on a flat up to 60, it goes thru that noise fairly quickly, but it is still there. But on the back roads with some hills, around 40 under load the noise is obvious. I just dont know what to do. Anyone else have ideas?

 

Mike, I remember reading an article a while back about some aftermarket torque converters needed to be shimmed a little to stop noise and/or vibration when the tcc locks up, I will try to locate the article with the specs and get back to you.

 

Wow, Joe, I got to see that article! I ran the car over the weekend with higher lockup speeds, and it seems to be less noisy. But I think I am just masking the problem by locking up the TCC past the speed of the noise.

 

Although agreed it could be something else , I did have a truck once that at a certain speed with the converter locked it made a roar as you got faster it would decrease and slower the same and it was indeed a harmonic. I had to have the muffler changed on the truck to make it stop and the customer still wouldnt pay for the muffler he said it didnt do it before but then he couldnt tell me for sure he had lockup before either