I have an 89 camaro(LO3) with automatic transmission, 2.73 gearing Im almost posotive..Ive seen a build sheet a while back on my car.

The rear also has 10 bolts. I need an answer ASAP so I can call SLP back and order my gears/differential.

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89 camaro 305 tbi, flomaster 3 chamber cat back, gutted cat, Edlebrock TES Headers, Exhaust cutout, Edlebrock open element, 160 degree T-stat, and a Stage 2 FastChip.

2 kicker comp 12"'s, polk for the rest. Phoenix gold xs2300 to subs, kicker impulse 404XI to 4 speakers, pioneer DEH- P7000R head unit, and finally a 12 disc changer. Full leather interior from http://www.MrMikes.com

 

if you tell them the year they ought to know what you have. i tihnk the 28 spline came out in 90, but not 100% sure. pull an axle and count the splines to be sure.

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ICON Motorsports
1st & 3rd
MM Black Diamond 538 F&AM

 

Im having a shop do the gear change so I dont want to take the axle apart. There is no way of knowing without opening it?

"An O.E.M. Zexel-Torsen for 7.5" & 7.625" differentials found in most 89-2001 Camaro s & Firebirds (with 28 spline axles). Will also fit 1982-1988 but requires changing to 28 spline axles. "

That is from SLP....it says most from 89-2001 have 28 spline. But the guy on the phone said only some did. I need clarification.

 

This has been a topic of debate lately but the general consensus has been that they started phasing them in in 89. I has been documented though that some ended up in earlier carsand the 26s ended up in some of the later cars. Ahhhh, the marvels of General Motors. Since you have an 89 there is no other sure fire way to know other than pulling the axles and counting. Pulling an axle really isn't that big of a deal. Just messy.
bsa

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"If they do not run, Then they will die." - Stonewall Jackson
#3
'87 IROC, 355 TPI, Converted to SD, 700R4, B&M Megashifter, 3.42, Trick Flow Twisted Wedge Heads, Edelbrock Intake, Accel Runners, Comp Cam, Crane Gold rockers, Lucas 24# injectors, Edelbrock headers, Flowmaster 3'' exhaust, Mallory Ignition, Transgo Performance Shift Kit, Corvette Servo, 2,000 Stall Torque Converter

 

I'd bet its a 26er. Mine was and so have many other 2.73 geared L03 cars. Get the carrier from SLP and then go to the salvage yard and find a 90+ third gen with a 10 bolt. No matter 6 or 8 cylinder. Grab the axles from the donor car. That is what I had to do. Or you can buy a new set of 28 spline axles for about 300. The choice is yours.

To pull/check the axle:

Jack up the car w/plenty of room to work. Take of the rear wheel. Unbolt the rear cover. Collect drippings optinal. With the car in neutral rotate the drive shaft so you can access the cross pin bolt. Remove the bolt and then remove the cross pin. You nay have to turn the driveshaft ever so slightly to allow some room for it to slide out. You may also have to give a little push from the top. After the pin has been removed push in on the brake drum of the wheel you removed. That allows the c-clip to fall (you'll hear it). After that gently slide the axle and brake drum assembly out and count the splines. Best way is with a magic marker so as not to lose count. Get readu to say DAMN 26 splines!

Be aware that if you rotate the drive shaft too far with the cross pin removed the spider gears will move out. No problem! If they do just fit them back in while turning the carrier. Watch out for the paper thin races they sit on!!!!!! They may fall out too. You'll need to line everything back up before the cross pin goes back in.

Good Luck!!

 

yep, RGZWS6 is probably right..
I bet it's a 26-spline axle, just like mine was.