I have been driving my Iroc with low oil pressure and aside from that it has been fine. I had the trans rebuilt and a new converter put in about a year ago. I am in the process of building a new engine so that is not the prob. The other night I stopped at a redlight to turn down another road. When I pulled away from the light and turned something made a single bang noise. The engine was running kinda funny but it was shifting just fine. I figured my original problem of low oil pressure was just catching up to me. Anyway I got where I was going and let the car rest. When I left there about 30 min later the car was driving fine (funny noises from engine sounds like a lifter) but the trans was shifting fine. I get down the road a little ways and stop at a redlight. When I leave the redlight the car won't shift. The rpms go up the car gets to like 35 and won't go any faster. It feels like it is in neutral. I called the trans shop that did the rebuild and they said when I get the new engine in they would take a look at it. But if it something I can fix while I have the old engine out I would rather fix it. Any suggestions or comments will be welcome.
Thanks

 

C'mon doesn't anybody have any suggestions as to what it could be. It just doesn't feel like the trans is the culprit. I checked the fluid. It is where is should be on the dipstick, bright red, no signs of metal shavings, no burnt smell. It just feels like the torque converter is never fully spinning the transmission. If it is the torque converter I would like to replace it when I already have the engine out, not have to go through it all over again. Thanks

 

Did you do any manual downshifting by any chance when you heard that clunk?

 

no, not when i heard the clunk, it only hesitated for a second then the engine started making a "bad main" sound and I already knew my oil pump was shot so I figured it was almost at the end of its life. I stopped the car for about half an hour and then it was driving fine. When I got about 2 stoplights up the road I had to stop at the redlight. When I left the redlight it wouldn't shift. I downshifted then to "1" and the trans downshifted so it was in 2nd. Now it won't shift past 1st and won't go over 35 no matter how high I rev it. It will peg the tach at 7500 and not go any faster. I don't know if the tach is accurate but you get the idea, its accurate at lower rpms, idles where it should, etc.

 

Whens the last time you checked the fluid? Full? My bro's 87' silverado is doing the same. Except it wont come out of 2nd. I think your trans just may be shot. But im not an expert or anything. If you do have to change it, while its out try and put a new oil pump in. Just my 2 cents.

 

trans fluid is full, bright red doesn't smell burnt, was rebuilt about a year and a half ago. I saw a post on another message board about someone having the same problem. They replace the torque converter because when they took the old one off the splines were sheared off. New torque converter worked great and no more problems. I have a whole new engine going in there so I don't have to worry about the oil pump. When I had the trans go out before I had it rebuilt it took like 6 months before I didn't have anything but second. This happened in one night. Thanks for replying