FastestBusaAround

08Z -- intermittent grinding on 1,3,5 only. Today, I shifted from 2nd @87 straight to 5th and it ground so bad, it felt like it was trying to hit reverse, which I know it wasn't. Clutch was fully depressed right to the floor...

It usually happens under WOT, but from time to time driving like a *****, either up or down shifting will cause the grind...but only in the 1,3,5 position, nothing from 2,4,6

Also, under power, it seems that when you're not going from one gear to the next sequentially, is when the problem occurs most frequently. Clutch is perfect, tranni fluid just changed with original GM fluid and the car has only 9K miles. It's been like this for the last 4K miles. Synchros? I'm betting it has to go to GM, but seeing as how it's so intermittent...it may be a while until they can actually see the problem occur...

C5 Frank

I believe there is a TSB for the '08 Z tranny and grinding. If you do a search you will find lots of info.... Pretty sure you will get a new tranny.....

walterm32

I think your right. Sounds to me like the synchros are going.

joe11204

I had the same problem in my 08Z. When trying to engage 5th gear at highway speeds it would grind so bad I thought the solenoid was bad and I was trying to shift into reverse.

The dealer swapped out my trans for a new unit. (Long story with that).


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satans csex

Yea my car wont go into Reverse lol . She sounds no where near stock. So im going to have to pull mine out sometime this week and redo her up!

FastestBusaAround

Just checked edmunds.com; no TSB on that issue...I'll check the site here.

mr.radon

2@87mph to 5th, you are asking the sync's to bring the input shaft speed way way down. But they should not grind.