SKZ28

iTrader: (2)

My car is a '98 Z28 M6, new GM slave and master, and new LS7 clutch. The car shifts great at any gear without any grinding or anything, except...

A little bit ago I was out cruising on the freeway and there was nobody around, so I had a quick run. During the 4-5 shift it had a really quick grind as it went into gear. It stayed in gear and didn't pop out or continue to grind or anything abnormal. I slowed down some and sped back up again, and once again it happened as I quickly shifted into 5th at high RPM's.

So, I tried it a 3rd time, but this time as I got close to redline in 4th and prepared to shift, I took it easy and shifted slower and more casually into 5th, and it didn't grind. It never grinds 5th (or any gear) when driving normal. It downshifts from 6th to 5th easily without a problem.

I'm assuming this is a syncro issue, but I've done a lot of research on here and 5th doesn't really seem like a common problem. Am I on the right track, or is there something I am missing? Will the grinding eventually get worse?

LS123

iTrader: (11)

What is your current mileage? I have seen more plastic fork pads broken causing too much play and not engaging the syncro all the way in. This is 1-2 shift fork but you get the idea.....





What's left of the fork pads......

bmartin8

HEY! That looks fimilure. This is a perfect example of why you recomended those 5-6 bronze fork pads!

deadhorse66

iTrader: (2)

That, or stop speed shifting to 5th. I would recommend the latter, the bronze pads are a little more labor intensive.

SKZ28

iTrader: (2)

Yeah, it was the first time I did it and I don't plan on doing it again. I was just wondering if it was a common problem? Hopefully not a sign of things to come. I don't want it to get worse and start doing it every time I try 5th

bmartin8

It will if your fork pads are already ruined, which it sounds like they might be. I agree tho, why do you need to powershift 5th? Are you running some crazy gear? You hit 5th at what 120mph?

deadhorse66

iTrader: (2)

I would think not. The ones I usually see with keys spit out or broken fork pads are 3-4 and 1-2 in that order. Take it easy and you should be fine.

Darkreign2049

Mine does this also, but not all the time. Also this past weekend I took a trip out of town and when I downshifted into 5th from 6th it would grind going into gear. If I down shifted to 4th then 5th it would go in no problem.

LT1TA

iTrader: (17)

i just bought a car with a "stage 3" tranny. it grinded into 5th very slightly. after a while, i has become so bad towhere if i try to shift into 5th, it will grind so bad you can feel the tranny moving. i go from 4th to 6th but the tranny will sometimes not let me leave 6th. i don't want to seem pesimistic, but i would take care of that syncro

SKZ28

iTrader: (2)

The car still shifts perfectly, whether it's daily driving or racing. This was the first time I've encountered a problem, and I don't see it being a problem in the future seeing as how it's avoidable and unnecessary. I really don't think it's anything to worry about as long as it doesn't get worse. If it starts to grind during everyday driving, that's when I'll start to worry.

Stock gear. It wasn't a powershift, but more of a "speed shift". I shifted quickly, but I let off the gas when I shifted. There really isn't a need to do it in 5th, I just hadn't done it before on the 4-5 shift and I was surprised at what happened when I tried it. Yeah it was somewhere around 115mph IIRC.

LS123

iTrader: (11)

LOL, yes Brian, that is your trans but now it's all better with all good stuff. I got it all done tonight and be over Sat to install it. Sorry to hijack.

deadhorse66

iTrader: (2)

You guys need to make sure the stops on your shifters aren't interfering. I've seen that more than once.