transmission problems

Hey,
i've had quite a few tranny problems in the last year and i'd like soem help figuring out what the problem is...in april i bought a 90 sc 5 speed that needed blocking rings and a clutch. i also put on a new slave cylinder. in august i was power shifting from 2nd to 3rd and got between 3rd and 5th and bent one of my shafts. so all the blocking rings are still good. i bought another transmission and had a guy switch out my blocking rings. this tranmission has no play at all. the guy that rebuilt the transmission said its the tightest one he's ever seen or felt. ok no here's the problem. it grinds in 2nd and 3rd. so the blocking rings are good clutch is good and the slave cylinder is good. and if it was the clutch or slave it wouldn't just do it in 2nd and 3rd. i had ATF in it then i switched it to 75/95 synthetic to see if this would fix the problem. then i added trans-x friction modifier to see if that would help. what else could be the problem?? Thanks in advance
Kyle

You could try switching to GM syncromesh tranny fluid and hope that works otherwise you may need to open up the tranny again to check out the 2nd and 3rd gear syncros to see if they are bad. Good luck!

Shane

I agree I run syncromesh in my m5od and it works awesome. The atf breaks down in no time the syncromesh lasts darn near forever plus it seems to shift better.
Alan

there's more

I forgot to mention that it only does it when the car is cold. when the car is warm it doens't grind at all. i drove for over an hour last night then got back in my car 3 hours later and when i shifted it ground. when i got closer to my house and was stopping at stop lights and shifting it didn't grind. what now?

Also, could it be the synchro's instead of the blocking rings? my tranny man said everything was tight and everything inside looked like new. so it is a freak piece of sh%t?

The blockers should go bad before the syncros do. Maybe its low on tranny fluid?

Shane