Grind going into 3rd gear .. Need Oil recommendation

[Onefast99gsx]

Well the tranny needs rebuilding as it has a slight grind going into 3rd (only at high rpms). I have a blend of Redline MT-90 and MTL in there now. I want to go racing this coming weekend and get one more race day out of it before tearing it apart to rebuild.

Because of the grind, would I be best to run just a straight synchromesh like Pennzoil or run a blend of 2 to 1, Pennzoil Synchromesh and a quart of Heavy Shockproof?

I'm wondering if Shockproof would help it or make it worse. I have 1 quart of it left.

I believe the grind is a result of numerous No Lift To Shifts. I also missed 3rd once and ground it some.

Thanks.

[Shane@DBPerformance]

Try straight BG/GM/Pennzoil Syncromesh, if you just want to be able to shift. Thicker fluids are usually to help protect the gears, not shift very smoothly. Then get ready to replace all the syncros and possibly some gears.

[Goat Blower]

Straight Stinkromesh will probably make the grind worse. Try a mix with some shockproof, it might limp you along for one more race.

[Onefast99gsx]

Ok, Here's the scoop. I put in 2.5 qts. of straight synchromesh tonight and took it for a beating. 1, 2, & 4th shifted better than it ever has. Very smooth. Third still ground some but not quite as bad. Any grinding is bad though. So i took it home and drained out 1 qt. and put in 1 qt. of Heavy Shockproof and took it out for another beating. To my amazement, the grind was virtually gone. I tried a couple of speed shifts and it was great. The heaviness of oil must help to slow the syncho down. The only bad thing I can say about it, is the rest of the gears didn't shift like butter as it did with the straight synchromesh in.

[Shane55113]

i did not know you could blend those two oils together.