ccj

Finished a track day yesterday in my C5Z and noticed on the drive home I have a loud howl on the freeway, increases under load, gone off-throttle. Shifts well, runs well, but with the ever present howl. Car has diff and tranny coolers but its possible the pump died (I know one of them was working b/c I could hear it when I turned on the switch).

Wondering if anyone has a recommendation to pull a differential/transaxle and potentially review and repair the diff/tranny cooler pumps/heat exchangers. ??

Thanks
Clarke

NW94Z

There was a shop specializing in differentials in Kirkland but I recently learned they have closed.

I've recently diagnosed the diff as bad in my C5 Z as well. Similar howl to what you described. Speed related, becomes very clear at 29-30 MPH, disappears as soon as load is removed from the driveline.

Going to flush and replace fluid first then go from there. I've already begun to look at options to buy a new diff and swap them myself. Apparently the diff can be removed without dropping the entire driveline or even transmission.

ccj

Looks like my friends shop is up for pulling the transaxle. But we are likely looking for someone to replace / rebuild the diff.

NW94Z

Let me know if you find a reputable place to rebuild the diff.

billla

https://www.kirklandtransmission.com/ would be my first call.

ccj

Kirkland wasn't interested in doing a transaxle from my Z06. I did not have a conversation with them myself so it could be they don't like transaxles, corvettes or specifically track car stuff. Not sure.

billla

Kinda surprised - not sure what "did not have a conversation with them myself" means, but I'd encourage you to call and talk to Tony directly.

On factor is that they only have one lift where they can drop the drivetrain out, so scheduling is a factor.

Michael Clemans

GP Automotive is South Everett off 1238th close to I5. They repaired my drivers side differential on my C5 and did an awesome job.
https://gpautomotive.net/

ccj

My friend's shop is pulling the transaxle. I have been waiting for lift space at his shop. He talked to Kirkland as they are nearby my friend shop.

CamarosRus

Call this company in Everett and ask their advice.................

https://www.yukongear.com/

billla

Not too many shops are going to take on work like that - if there's an issue, then shop A points the finger at Shop B. So I can understand them taking a pass...

ccj

That's how the national shops work that do transaxle rebuilds. Local shop pulls it and someone else rebuilds it. No different than a crate engine in that sense.

billla

Sure; but there's a difference between buying a part and having local shop do piece part work.

Anyway, good luck - I hope you find someone to square it away for you.

ccj

I get that. Dropping it off today. Expect transaxle will be out by the end of next week.

ccj

Shop pulled the transaxle this week and dropped it off for rebuild. Shop owner said the fluid was very metallic, but that was no surprise based on how it sounded.

CamarosRus

What shop pulled the diff from Car and what Business is doing actual rebuild ???

ccj

EVOMS (They actually a Porsche shop) in Kirkland, WA pulled the transaxle. The owner Sam is a friend of mine and did the head/cam/intake, momo steering wheel and some other stuff for me for a few years.

NW Differential in Monroe, WA is doing the rebuild.

NW94Z

You don't by any chance know if NW Differential was located in Kirkland previously?

ccj

Not that I know of. There is a shop near where Carb Connection is. They are the ones that Sam Stone at EVOMS went to talk to first. They were not interested in the work, but I don't know why.