ok , did the ls 5th gear swap on my y1 lsd tranny. drove it for a day and no problems . next day i go to get on the highway to test out the 5th gear . i get on the ramp and start to speed up in 3rd gear , i go to shift into 4th at like 6k and it grinds hard . then i went to 5th at around the same and it grinds hard again. i noticed the grind is a fast grind like the synchros aren`t even lining up. if i let the rpms drop all the way down it will go into gear but nothing up higher will go into gear. all i touched was the 5th gear , and i know i did it right . any ideas ?

 

Only thing i can think of is maybe u did something wrong, lol, even though u say opposite. If it didnt grind before the swap, and it does now, pull the tranny down again and retrace your steps. Its gonna take some time.

 

i THINK it common to grind into 5th gear after that swap because of the difference in ratios from 4th to 5th. i think i remember reading about someone else who did the swap and that double clutch to slow the syncro's down? as for the 4th it sounds like you must have done something to it but i've never done any work on trannies, just read about the swap and contemplated.

 

Yes there is a massive difference in the 4th to 5th ratio now, so you're trying to shift into 5th while the gear/shafts are faaaaaaaaar from being in unison. try some gm synchromesh friction modified gear oil, people like that stuff.

 

GM Synchromesh, it's the shiznit , fixed my 3rd gear grind

 

biggdogg, i'm sorry to hear that. when we did my 5th swap into the j1 tranny it's worked fine. I know when we replaced mine before we put it back in we checked it and re-checked it before we shut the casing again. My tranny hasn't grinded ever before and still doesn't so I don't know what to tell you. It'd just have to be opened and looked at where it isn't lined up right w/the syncros. Possibly the 5th gear syncro didn't sit down right after the swapover? I had that problem b/c of not linin it up perfectly, but I had a spare syncro sitting around.

If it turns out that something's gone to crap I've got 90-91 ls 1-4th gears layin around.

 

thx guys . we checked and double checked the gears before we put it in . switched it into every gear while it was out of the car to make sure it fell in good. the first night i drove it i had no problems what so ever . the very next day this happened . i`d hate to drop it 3 days later after it`s been sitting in my garage for a year . gonna try the synchromesh and see if that fixes it .

 

Hope the syncromesh works!

 

there is no reason why this difference in gear ratio b/w 4th and 5th would cause problems. Incorrect assembly is your culprit...

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by EFSiR &raquo;</TD></TR><TR><TD CLASS="quote">there is no reason why this difference in gear ratio b/w 4th and 5th would cause problems. Incorrect assembly is your culprit...</TD></TR></TABLE> Well it would cause more grinding than gears that were closer spaced in ratio. The sychro hub and the gear are further from unison, requiring more synchronization than normal, so a quick shift with a wide spaced ratio could result in a severe grind.

 

I dont think the grind is going to be from the ratios being off! Thats why the invented the syncro. I am guessing something you did wrong or maybe the stuff you put in was crap to begin with.

 

okay , i tried the synchro mesh and its not working . guess im gonna send it to gearspeed and have them build it . here goes a grand . jeez !

 

sorry to hear about your misfortunes! that stinks! baaad

 

Well if ur gonna drop it out to send to gearspeed, then split the case again and go through it before u box it up. Im sure u have a factory service manual you can work with. Maybe u will find something that was put back backwards or something.