I have a slight grind going into 4th gear and alot of grind in i rpm.I have seen redline racing oil work wonders but im not sure which fluid to buy being that i have LSD and im not sure what weight any info would be great thanks

 

I heard of some GM synchro oil thingy. I read that it does wonders, search about it.

 

yea i use GM Synchromesh Friction modified...part # 12377916, its like nearly $12/quart ..a lot of people swear by it, but i personally use it just for the many vouches its recieved, its supposed to help the synchros and lube them up specifically to avoid griding..being friction modified and all it takes a lil' while for it to perform what it's intention were to help the synchros and all, theres too many threads on this, just do a search...but being LSD and all, i don't think you'd need any different tranny fluid/oil

 

hell yeah, that synnro mesh is what they put in anything with an LS1 or LS6, my buddy put somein his DA and his 3rd gear grind almost went completely away