I'm looking for a 3.73 gearing positraction rear. Well I only want to replace the stuff I have to, considering everyhting is all in great shape, so why bother? I want to know exactly what I need to replace, and how much it'd cost. Thanks.

BTW I need to know number of splines and stuff like that, just in case My rear is stock.

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1992 Pontiac Firebird (stock)
- 5.0L V8 TBI / Automatic Trans / Every option, excluding leather
- Killer car audio system:

• Aiwa CDC-MP3 head unit
• Rockford Fosgate 360a2 amp
• pair of 12" MTX Thunder 5000s in a custom box
• Pioneer 3-way 6x9s, soon to add more more more!

 

You have 28 spline axle shafts. The SLP takeoff will go right in. If you want to change the ratio though, you need to dig the pinion out of there and set the depth. Usually a .035" shim under the pinion head bearing is a good starting point (Every ten bolter I did anyway has a .035" stock from the factory)

If you have the equipment to remove the bearing from the pinion, you could use your stock shim as a starting point. This is probably the hardest part to do yourself because if the depth is wrong and you pressed the bearing on, you need to remove it w/o damaging it (difficult)

Backlash on the other hand is a piece of cake. You need an assortment of shims because I converted to the SLP takeoff and you'd think by reusing the stock shims on the sides of the carrier, it would position the same ring gear in the same spot, but in reality the carrier was way to tight to even fit in, and the stock shims are cast one piece.

Once you get your backlash set with the carrier at zero endplay (No side-to-side slop), you could roll the carrier half way out and slip one more thin shim in the passenger side and tap it home to load the bearings.

 

Do you think its a better idea to find an entire rear end?

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1992 Pontiac Firebird (stock)
- 5.0L V8 TBI / Automatic Trans / Every option, excluding leather
- Killer car audio system:

• Aiwa CDC-MP3 head unit
• Rockford Fosgate 360a2 amp
• pair of 12" MTX Thunder 5000s in a custom box
• Pioneer 3-way 6x9s, soon to add more more more!

 

I scored a rear out of a 89 v6 at the j-yard complete with 3.42's for $24

After finding out they were 26 splines I got axles out of a 92 v6 for $15 a pair.

SLP takeoff on sale $80

New drums, brakes, wheel cylinders and springs from autozone for around $60-70 or so


I was happy with the 3.42's so all I did was take out the carrier, swap the ring gear and since I already had some parts (shims, races) laying around I set the SLP in re-using the bearings that they left on there (looked OK to me) and set the backlash.

I took me about 4 hours to re-do the rear (including freshening the brakes)

It's so much easier with it out of the car. I did a full carrier/ring & pinion swap in the car and it costed way too much and was the most aggrevating mechanical thing I ever did. That and the fact that while crushing the crush sleeve (I didn't have impact tools at the time) so I used a breaker bar and 'jacked up' on the handle. Damn car kicked off the jackstands and almost crunched me... Never again... Plus I had to fabricate a pad to bolt on the yoke with a big hole in the middle and a long handle to keep the thing from spinning on me.

If 3.42's sound good to ya, just get a complete rear from the J-yard (28 spline rears are hard to find, but don't sweat it... a 26 will be OK) out of a later v6 with auto 2.8 or 3.1 multiport injection....

Pull the cover and the edge of the ring is stamped with the ring/pinion teeth count and divide them to make sure the ratio is OK. Another canidate is a 305 HO car, you may get some 3.73's then, but since these cars are older, you may have more gear wear, SAE instead of the metric brake lines and other PIA little diff's.

Autozone has this degreaser in an aresol that worked great to clean out the inside of the housing, then I stood it on edge to clean the axle tubes out. Then I just wiped a little moly on the wheel bearings and squirted some lube in the back there to saturate the pinion bearings so they're not dry. Then you could at the last moment before swapping the rear out of your car, pull the 28 spliners and put the c-clips/retainer and drums (or rotors) on and your set.

It's the easiest/cheapest way I've found anyway with no downtime like re-doing the axle you already have.