Diff Rebuild -- Is it worth it? - Page 3

**JimmyH** · #31 (**permalink**) 08-24-09, 02:17 PM

Quote:

Originally Posted by rand49er

Actually, someone who's opinion I respect mentioned to me that there was very, very little difference between the 2nd and 3rd gen units. The biggest difference occurred when going from the 1st gen unit ... at least that's what I heard.

I have 3rd gen, and it looks identical to the pictures of the 2nd gen. Of course that is just the casing.

rand49er · #32 (**permalink**) 08-24-09, 06:42 PM

I got a vid with audio. The noise is apparent, too. Need to edit it down a bit (unless you guyz like watching a bit of how exciting South Lyon is

).

Maybe get it done later tonight and post it up.

ewill3rd · #33 (**permalink**) 08-24-09, 10:17 PM

Gen I = junk. It is hard to believe there are any left on the road except one that has been sitting in a garage or driven by an old lady who bought one by accident.

Gen II = better, but still prone to "case distortion" and noise. Not so many grenading from wheel hop or other sources of intense launching. Look for photos of difference between 2 and 3...

Gen III = the best GM has. Started in early '08 and has physical differences from the other 2 versions. The pinion housing assembly is very different and stronger. I have installed a few of these and have not had issues with case distortion or anything else for that matter. No seal leaks, no bushings (yet) no nothing.
I am sure someday someone will do something to one but so far so good.

Again there are a bunch of pictures (that I took) floating around that show the night and day difference between II and III's front pinion housing assembly.

stuckey · #34 (**permalink**) 08-24-09, 11:05 PM

Quote:

Originally Posted by ewill3rd

Gen I = junk. It is hard to believe there are any left on the road except one that has been sitting in a garage or driven by an old lady who bought one by accident.

Gen II = better, but still prone to "case distortion" and noise. Not so many grenading from wheel hop or other sources of intense launching. Look for photos of difference between 2 and 3...

Gen III = the best GM has. Started in early '08 and has physical differences from the other 2 versions. The pinion housing assembly is very different and stronger. I have installed a few of these and have not had issues with case distortion or anything else for that matter. No seal leaks, no bushings (yet) no nothing.
I am sure someday someone will do something to one but so far so good.

Again there are a bunch of pictures (that I took) floating around that show the night and day difference between II and III's front pinion housing assembly.

so...will the standard cts diff work for the V's??? did the cts diffs change in 06 with the V's?

**JimmyH** · #35 (**permalink**) 08-25-09, 12:19 AM

Quote:

Originally Posted by ewill3rd

Again there are a bunch of pictures (that I took) floating around that show the night and day difference between II and III's front pinion housing assembly.

What about from the rear of the car? They looked pretty much the same to me.

ewill3rd · #36 (**permalink**) 08-25-09, 09:32 AM

From any other angle I don't see much of a difference but I have never really sat down and studied them.
If they did make changes they are subtle.

The physical shape and size of the rear diffs are identical.
The Base car and other Sigmas that use this same setup got the new pinion housing as well but I think the catalog does show different part numbers even if the base car has G80.
It might be the axle shafts or something... I don't know. I haven't studied it enough to know.
Most of what I am saying here has to do with observation over time and not much else.

rand49er · #37 (**permalink**) 08-25-09, 10:18 AM

Quote:

Originally Posted by stuckey

so...will the standard cts diff work for the V's??? did the cts diffs change in 06 with the V's?

Don't have limited slip, do they? Too bad, too, since there's a buh-zillion of 'em out there.

Quote:

Originally Posted by ewill3rd

Gen I = junk. It is hard to believe there are any left on the road except one that has been sitting in a garage or driven by an old lady who bought one by accident.

Gen II = better, but still prone to "case distortion" and noise. Not so many grenading from wheel hop or other sources of intense launching. Look for photos of difference between 2 and 3...

Gen III = the best GM has. Started in early '08 and has physical differences from the other 2 versions. The pinion housing assembly is very different and stronger. I have installed a few of these and have not had issues with case distortion or anything else for that matter. No seal leaks, no bushings (yet) no nothing.
I am sure someday someone will do something to one but so far so good.

Again there are a bunch of pictures (that I took) floating around that show the night and day difference between II and III's front pinion housing assembly.

Whoa! Thanks, Bill.

This is VERY interesting! So, could getting a Gen III from Luke really let me see as much as 100k miles of trouble-free diff? THAT would be worth it.

Would love to see those floating-around pics, again. I vaguely recall them, but as a diff-dying denyer in the past, I didn't focus on them very well. Can anybody find them?

Twitch · #38 (**permalink**) 08-25-09, 10:25 AM

Quote:

Originally Posted by rand49er

I'm sort of coming to the opinion that buying a new one is a bandaid; I'm going to get another 10k maybe as much as 12-15k out of it, and that's not worth it. The same with rebuilding it ... I'm just putting a turd back together with the same weaknesses.

Someone posted where some of the Cobra guyz were bolting a brace to the exterior of their diffs to stiffen it, presumably from distorting during high torque transfers. Certainly not the best thing, but I don't think anybody's looked into it for our diff.

The ideal thing, outside of doing a full-blown redo of the Getrag, would be to take a few dozen failed diffs, take 'em all apart to determine which components are failing most frequently, then propose a redesign of those components or related ones to eliminate that failure mode. If the case itself is flexing too much (and causing internal problems), then design an external brace setup that would stiffen the case ala the Cobra guyz. If we're talking about very small deflections, we're probably talking about one beefy-a$$ brace. It would take someone who's knowledgeable about diffs I would think. But, alas, that's the ideal world ...

Wouldn't a diff brace transfer more noise to the cabin?
Do you still have your Kars III on the car? At least remove the pinion brace. That'll quiet it down a bit.

rand49er · #39 (**permalink**) 08-25-09, 10:40 AM

Quote:

Originally Posted by Twitch

Wouldn't a diff brace transfer more noise to the cabin?
Do you still have your Kars III on the car? At least remove the pinion brace. That'll quiet it down a bit.

My thought was a brace that somehow wrapped around the diff case itself securing it better and preventing (limiting) the case distortion. It wouldn't be attached to anything but the case, so no noise transmission. Of course, maybe it's a dumb idea totally.

Yeah, I might remove the KARS kit. I just wanted to be "for sure, for sure." Maybe I could isolate the noise better. I got some video with audio yesterday with a unidirectional mic strapped to the underbelly, but after listening to it, I'm not sure if what I'm hearing in that is just wind, even though I put a wind sock on the end of it. If I get a chance today, I want to remove the rear seat bench, place the mic inside the car pointing down at the diff, and do it again. Having the time today is the question.

ewill3rd · #40 (**permalink**) 08-25-09, 02:22 PM

KARS and the BMR will transmit some noise to the body for sure. I mean when it is all said and done this is a gearset, and gearsets make noise.
The issue is once the pattern goes far enough out the gears won't mesh right and you'll get A LOT of noise.

Let me see if my photobucket has the pics still....

This is the old style with the updated seal and yoke. The original seal and yoke look a tad different but what you are looking for is the shape of the nose piece.

Here is the updated style that I call the '08 or the Gen III as it seems to have been dubbed.... notice the front piece, you cannot see the seal at all and it has a longer tapered nose piece that goes behind the dust sheild.