Rear Ends - Third Generation F-Body Message Boards

Y2KFirehawk · 02-27-2002, 10:30 PM

I've seen the fourth gen users on another group I frequent talk about this part from SLP that turns your rear end into a posi or something like that. As an end result, I'm looking to have 3.23 or 3.42 gears, anything is better then the 3.08 that is in there right now. I was wondering if that part is something that would apply to my car or not. I believe it was a Zexel Torsen or something like that? Thanks in advance.

Mark

--- Also, if I am wrong about that part, do any of you know any websites that I could find a rear-end for my car?

TomP · 02-28-2002, 02:02 PM

Welcome to the board! Yeah, the SLP take-off will fit your car. In mid '88, GM went from a 26 spline axleshaft to a 28 spline axleshaft. This means that '82-'87 F-body owners need to change their axleshafts for the later model, stronger, 28-spline ones, if they want to install the SLP unit. '89-now owners have the correct axleshafts. '88 owners need to pull the diff cover off and count splines.

You could find a 1989 2.8 V6 f-body with an automatic trans in a junkyard, and swap that axle onto your car. Then you'd get 3.42's, and could have the SLP posi put on.

I put a 3.73/posi/disc axle on, from a 1984 Firebird Trans Am, with the manual trans, and High Output motor. It cost $150. I then spent an extra +$700 on it, most of which was re-doing the rear discs. (82-88 rear discs were recalled, 89-ups are perfect).

The 3.73/posi was defintely worth it, though. And once I got the rear discs working (I had to rebuild them using GM's recall kit, and bought a Phoenix Injector V12 from http://www.phxsyss.com to make my life easier!), they are AWESOME.

So you could also find an '89 Trans Am with rear discs, and put that onto your car- but you'd also have to buy 3.42 gears ($200) and have them installed ($200) along with the posi ($75).

Just something to think about when you switch axles...

I also used http://www.por-15.com on my axle, and it came out great. I recommend it! I bought the $20 Super Starter Kit, with semi-gloss, and it was just enough for the whole rear axle. The only other things I replaced on the axle were the rear axleshaft bearings and seals, and put new gear oil & posi additive in.

I think the cheapest bet for you would be to find the '89 V6 automatic's axle (3.42) with rear drums. That way you can swap your "known working" drum assemblies onto the donor axle. You should still replace the brake hose and e-brake cables and axleshaft bearings/seals as a matter of "while it's apart, do it now". Figure, an axle for $120, SLP take-off for $75, brake hose for $30, e-brake cables for $60, new rear brake shoes $20, axleshaft bearings $15, axleshaft seals $8, brake fluid $10, axle fluid $20... that's, what, $360, if you have the tools to do the SLP differential install yourself? This is as opposed to new gears ($400) with the SLP ($75). The choice is up to you...

...but it is nice to say you did the work all by yourself!

Y2KFirehawk · 02-28-2002, 05:01 PM

Thanks so much man for your reply and taking all that time!! I really appreicate it. I'm most impressed with the boards here, and learning more and more as I keep reading! And also thank you for the warm welcome! I can't wait till they decide on a T-Shirt, becuase I want one so bad!

I printed your post, and I'm not sure what I'm gonna do yet, but yes, I'll be doing the work myself =o) Thanks again!

Mark

Project: 85 2.8 bird · 02-28-2002, 10:17 PM

PowerTrax

see my post on the other site

fly'n_low-3.1 · 02-28-2002, 10:35 PM

Ramair90 <--------proud member of "that other site":hail: :lala:

sup guys ive been really busy and havent been able to post since i registered a long while back...ive been a guest for a couple years i thought i might as well contribute

that posi unit would be awesome in our cars...wwasem go for it man!!!:hail: :lala: --fluffy

Adam

WaynesRS · 02-28-2002, 10:48 PM

I don't know the name of the product , I MEAN , her name

, but there's this fine girl in my art class .She's got a real nice rear end .It looks like a nine inch, but Im not sure !

Project: 85 2.8 bird · 03-01-2002, 12:24 AM

welcome to the show Ramair90, er I mean fly'n_low-3.1

TomP · 03-01-2002, 11:14 AM

No problem, WWasem! I'm usually long-winded in my replies, glad I gave you what you needed. "One of these days" (and the long-timer guys here in the club know what I'm about to say) when I get my webpage up, I'll have a whole section dedicated to my 3.73/posi/disc axle swap. So if you have any questions at all about it, let me know. I thought it important that I pointed out the cost comparison. Honestly, if it wasn't for getting those ($*@#ing) rear discs, I'd be a sad man right now for spending that much to get 3.73's and a posi.

Granted, you could always throw a junkyard axle on without re-doing the e-brake cables or wheel bearings and without painting the thing... but at least do the brake hose. All brake hoses deteriorate over time, and become "internally" plugged due to the rubber falling apart- so if you don't replace it when you do the axle, you'll have to replace it eventually.

maverick544 · 03-02-2002, 01:06 AM

SO how much is that SLP upsgrade.

krazycracka55 · 03-05-2002, 06:14 PM

was wonderin about swappin stock gears to 3.73??
is it possible...............

krazycracka55 · 03-05-2002, 06:15 PM

i have a 92 RS v6!

TomP · 03-06-2002, 01:38 PM

Sure, we've got the exact same axles as the V8 guys do... that goes for size, strength, and internal parts.

krazycracka55 · 03-08-2002, 01:23 AM

ok ok ok so does anyone know the pick up gained from swapping from stock gears up to the 3.73??????

1992 RS 3.1 v6

Monkie · 03-08-2002, 03:04 AM

Get 3.73s you will love it off the line and it wont cut out your top end. Me personally Im going with 4.30s

WaynesRS · 03-09-2002, 10:01 AM

DOOD !!! MY car is just like yours , except I dont have the t-tops .