Jorlain

iTrader: (4)

So, I have two rear axles.

A 26 spline, DM Disc with a 3.73 open differential, and a (assumingly, since it's from a 90) 28 spline, drum with a 2.xx open differential.

I like the idea of discs, even though they're the DM discs. Another bonus is that I already have a 3 Series gear set, I just need a posi carrier.

On the other hand, I would prefer to have a 28 spline axle... But the idea of needing to upgrade the brakes (assuming the 9.5" drums probably aren't conducive to stopping quickly) along with gears and carrier seems like a waste of money on a 10 bolt.

I'm really on the fence about which one to run with. Does anyone have any recommendations?

Thanks!
Mike

Drew

iTrader: (58)

None of the above? The cast iron calipers gobble bawls. They're complete garbage, the drums are better. If you change a carrier, it'd be silly not to change the gears too. Otherwise, you'll be re-setting up the used gears.

The 90 rear with a new carrier and gears, either with the drums or upgrade to PBRs or something similar would make the most sense. As much as you'll spend doing any of the above, you might as well do all of the above and actually gain something from it. All considered, the stock drums aren't bad aside from being more involved to service.

Jorlain

iTrader: (4)

That's more or less the way I was leaning, but I wanted to make sure I wasn't crazy for thinking the drums might be better than the DMs.

Thank you for your input!

Ozz1967

iTrader: (4)

disk is better than drum in nearly all cases. Also, the 28 spline axles will fit in the older axles perfectly. Just swap over the carrier with them.

big gear head

You can get a 28 spline 3 series Eaton Posi or other limited slip differential and use the 28 spline axles in the rear end with the 3.73 gears. All you have to do is reset the backlash and bearing preload when you install the LSD.

sofakingdom

iTrader: (1)

I'd throw all that crap in the trash and go to the junkyard and get something decent.

A stock rear out of a LS1/T-56 car would be the best way to go. It'll already have the good gears; already have the best disc brakes; already have the 28-spline axles; but WON'T already have near as many miles on it.

I might take the 3.73s out of the one before I threw it away; sell em to some "greater fool" and put the money toward the other.

You'll end up with a better product than ANYTHING you can make out of the crap you have now, for a fraction of the cost of buying gears, posi, axles, brakes, and whatever else, and piecing something together that might or might not actually work like you think it should.

Jorlain

iTrader: (4)

Thank you for the input, guys.

I agree that the best method would be a junkyard pull with all the goodies already there from a fourth gen, and the appropriate wheels needed. However, its pretty slim pickings around here. I haven't been able to find any third gen OR fourth gen cars in any of the yards around here, which would leave me needing to buy an entire car to just get the rear off of Craigslist or something. The upside to that is that I'd have front brakes I could swap, too, but it seems like people want an arm and a freakin' leg for things on Craigslist, haha.

Thank you again everyone for your input!
Mike

sofakingdom

iTrader: (1)

Everybody says that, everywhere.

Eff craigslist.

Try car-part.com. You'd be amazed. Look up a 98-2002 Z28 or T/A rear. There's like DOZENS of em around my area, all in the $400 - 750 kind of range.

Try this little mental trick for visualizing your project:

Starting point: a car, a pile of ... something, and a pile of cash

End point: a car with the rear end you want installed and operating reliably

Got the picture?

OK, now FORGET all that stuff in the middle about swap this and put this on that and buy this other. Instead, FOCUS on the best way to execute the path:

start ----> end

While minimizing the size of the pile of cash required.

If you're honest with yourself, you'll find that it DOESN'T involve ANY of the crap you have now, except for the car. (and maybe not even that... but we won't go there at this time)

Jorlain

iTrader: (4)

Looks like there's three within 150 miles that might work. Hopefully they'll get back to me soon as to which gear ratio and carriers they're sporting.

Thanks for the info! I didn't even know that site existed.

sofakingdom

iTrader: (1)

If you looked em up for 98-2002 Camaro or Firebird w 5.7L (LS1), they'll have the Zexel Torsen carrier. Ratio could be 3.23, 3.42, or 3.73.

Jorlain

iTrader: (4)

I just checked the units listed as 5.7L with T/C. The first one listed at 62 miles says it's a 2.73 without calipers for $700. The next closest is 152 miles away for a "Reman" units for an undisclosed price. Everything after that is 200 miles or more away.

sofakingdom

iTrader: (1)

T/C is traction control; you don't need that.

What's the big deal with that? A 3 hr drive each way? 6 hrs total? By the time you get done dinking around with gears, brakes, axles, bearings, carriers, and whatever all else, you'll have AHELLUVALOT more than any 6 hrs tied up in it, you can BLEE DAT. Driving that little bit to pick one up STILL is a better deal than piddling with that pile of crap you have now, and will STILL produce better results.

Jorlain

iTrader: (4)

I'll admit, it's mostly inconvenience. Six hours in a rattlebox pickup with three kids doesn't sound like fun, haha.

I know some places will ship yard to yard for a nominal fee around here. That might be an option, too.

sofakingdom

iTrader: (1)

Rent em out to the highest-bidding relative.

Jorlain

iTrader: (4)

Oooh!

Drew

iTrader: (58)

And the pertinent exception is the Delco-Moraine cast iron rear discs. This is a rear disc setup that GM issued a recall on, still couldn't figure out and outsourced an expensive alternative to replace. If GM couldn't make it work, how do you expect someone to make it work 30 years later with worn out junkyard and remanned parts?

On the other hand, drums work. They work well. They just don't look cool sitting behind a wheel, and they're more difficult to rebuild. Still, short of PBRs they're the best brakes GM offered on these cars OEM.

Back to the topic at hand...

I wouldn't overly expect to find a great used rear axle assembly in a junkyard. It's the first place I'd look, but I wouldn't completely discount getting the closest donor you can find to your end goal, and then sinking the money into it to make it what you want.

That said, if you can find the options you want in a junkyard rear and all you have to do is drive 3hrs (one way) to get it, you're doing well. I've driven 8hrs round trip for all kinds of parts. I've completely rebuilt a rear end. The driving was easier. I mean I spent at least a week of evenings under my car staring at the marking compound debating if I was happy with my gear pattern...

Jorlain

iTrader: (4)

I think I might've found a rear from a 98 Firebird. They say it's a 3.42 LSD. Were all 98-02 cars Torsens?

Not sure yet if I'd want to keep the 3.42s or mess around with changing to 3.73s.

I think I need to reread that fourth gen swap thread again.

-=Z28=-

iTrader: (3)

So, not to hi-jack, but I've always thought the disc brakes on my 84 were good? I always made sure to point that out when I was 16, back in 98. "Yep, shes got disc all around", I'd say..... heh.

Jorlain

iTrader: (4)

The Delco Morraine calipers are prone to failure and their adjustment system via the parking brake leaves much to be desired. Fully functioning, though, I think they're probably OK. But that's just me.

sofakingdom

iTrader: (1)

There's not a lot of difference between 3.42 and 3.73. In most situations, probably not worth the money and effort to swap.

Yes AFAIK those years were all Torsens if they were a V8 car. They were Auburn {insert gagging and hurling noises here} through 97.

Jorlain

iTrader: (4)

This is just me complaining and venting, but the guys at these salvage yards suck. One sold a rear out from under me while trying to arrange payment (I offered to pay by card over the phone, but they didn't want to do that until I came to pick it up), and the others are largely being unresponsive.

JamesC

iTrader: (5)

A quick word on the brake issue. I never experienced any problems with Delco-Moraines. That said, in the "upgrade frame of mind" that we all so enjoy, I swapped in PBR's. There are, of course, other choices.

https://www.thirdgen.org/forums/faq-...iscs-89-a.html

JamesC