Ok here's my dilemma, I have a bad gsr tranny (bad syncros i believe grinds 3rd at high rpm) that just sitting in my garage and a b16 tranny rebuilt last year with mfactory lsd, 3/4 hub, sleeves, and cc syncros that's in my car right now but now I decided I want the gsr gears instead of the b16 the b16 gears are way too short for my liking and what I'm trying to do, lsvtec turbo switching to corn for 600 plus

After doing some research to my understanding both the b16 and gsr mainshaft and everything on the mainshaft from both tranny are the same and b16 gears onto gsr countershaft will directly fit and work on a gsr tranny but my question is will it work vise versa gsr 1-4 gears (won't be needing 5th going with mfactory cuff) swap on to b16 countershaft work on a b16 tranny without any other modification other than swapping gears over? Can you tranny gurus please confirm and let me know.

 

b16 and gsr mainshafts are different. if you run a gsr 2nd you need a gsr main shaft.

 

Swap the good synchros/hubs/sleeves from the b16 to the gsr. You don't have to deal with the issue of the main shaft. You are keeping the gears with the proper mainshaft. So you are doing the rebuild to the gsr. The question about the LSD is did you get the LSD that has the size of the B16 diff or did you get the larger size and change the final drive to the gsr 4.4?

 

Thanks for clearing up the info regarding the mainshafts. About the gsr tranny yes my orignal plan was to replace the syncros/hub/sleeves but don't want to have to spend the money on a new lsd for the gsr since I already have one on the b16 tranny and yes the lsd that I have is the size of a b16 diff. What's the best way on how I should go about this? Basically I want to use gsr 1-4 gears with cuff on the lsd that's on my b16 tranny and put the b16 gears 1-5 into the gsr tranny with stock gsr diff for a back up

 

Keep the GS-R case, mainshaft and gears. Swap over the B16A diff and countershaft, as well as the synchros sleeves and hubs. Shim the diff.

 

Will do that ^^^ next weekend and report back how it goes. Thanks guys