Spinmonster

What transmission and differential are you running?

grubinski

F body T56, currently running a Getrag rear end out of a CTS-V, but a Ford 8.8 is about to go in.

G Atsma

CTS-V rear about to depart this world?

grubinski

it’s been noisy and clunky since day one… I’ve had two of them in there, a 3.73 that I bought brand new, and since then a 3.23 that I bought out of a junkyard. Even the one that started out brand new made a **** ton of noise.

So that’s the first thing that bugged me, the noise. The other thing that bugs me is that you can’t get them any more, and nobody can repair them, they’re put together really strangely.

The Ford rear end is cheap, and available anywhere. Parts are also available anywhere and everybody knows how to build them.

Spinmonster

Mike, you have to put gear oil in them.
C'mon, you laughed.
Did you get a ford rear?

grubinski

Yes, I got a 3.08 to replace the Getrag 3.23, but it's not going in until after summer. This is a convertible, summers are for driving the car, not working on it. Especially here in the Seattle area. :-)

johnzm

Hey,

been watching your thread for some time.. I have a mostly running LS3 NA miata as well. you drive yours quite a bit more than me, and mine is currently in its second year of living. I have a 3.72 with a 8.8. i have replaced the axle seals twice now in 1500 miles and my drivers side is still leaking. this seems to be semi-common issue. i will be keeping an eye to see how your upgrade goes.

grubinski

I replaced the axle seals on this one (sourced from a junkyard) when I put it in. Started leaking after a while. Put in two new seals. Still leaking. So then I started paying attention ...

I found several gouges in the aluminum case that I presume were caused by the seal removal tool, even though I **thought** I was just hooking the seal. I sanded the rough edges off of the gouges, and put a *tiny* smidge of black RTV in them. Then, while that was still wet, I installed the seals, with a *tiny* bead of black RTV around the circumference of the seal where the metal part seats on the differential case.

No leaks since.

grubinski

Oops, just noticed you’re talking about an 8.8. If you have an aluminum case, I suppose you may have the same issue.

I got a cast iron case 8.8.

johnzm

mine is the aluminum case. googling around it seems to be a not uncommon issue with leaks coming out of the axle to seal interface. i am starting to wonder if my issue is the axle bearing allowing too much play for the seal to work, or possible axle to bearing/seal diameter wrong. anyways i wish you luck as its not so fun to have axle oil flung over the back of the car/exhaust.

Htech

Good progress

G Atsma

Dude, that pic was FIVE years ago!
Troll elsewhere, please....