I'm just curious because this what I've been told but I'm not sure how accurate it is and I would like to know the truth.... From what I've known/been told is that the rear ends from 82-89 are the same, then in 90-92 they differ from the earlier years but are the same throughout their generation, then once more become different from 93-02. Is this correct??? other than one generation of rear ends possibly having 2 different pinion seals, are the rear ends the same for what I've listed?

82-02 was a 10-bolt BUT....the 82-92 was narrower & had weaker axles & posi units. But the 4th gen 10-bolts are a direct bolt-in. Just wider, so the rear tires sit out anout 1.5" more on each side. Since the stock wheels sit in so far, the typical spacer to use is a 2" one.

86?/87? (87 i think)-92 the Australian 9-bolts/Dana M78 (stronger than the 3rd gen 10-bolt) were available in some cars

91-92 the Firehawks got the Dana 44 (GREAT axle)

Then there is the disc vs drum brake issue.....Gear ratios....limited slip vs open, etc.

'82 got the Saginaw 7.5" 10-bolt ring gear, 10-bolt cover, and 26-spline axles. This continued until 1985.'85 IROC-Z with LB9 got "Australian" Borg-Warner 7.75" 8-bolt ring gear, 9-bolt cover. This continued through 1989 in the hottest F-cars.'85 the Saginaw got the ring gear enlarged to 7.625".'90 the Saginaw went to 28 spline axles. '93, the saginaw got wider by like 3", and got a 3-wire ABS setup. '96 some Z28 SS and Firehawks began getting a Zexel Torsen differential instead of the Auburn limited slip differential.'98, the saginaw went to a 4-wire ABS setup.

I always heard the Camaro didnt get the 9-bolt until 1987, thru 1989. The Trans Ams got the 9-bolt in 1985-89. The 9-bolts have 28 spline axles.

And both f-bodies went back to the 28 spline 10-bolt in 1990, but some 1990 models had leftover 9-bolts.

9-bolt in Camaro: my sources agree on '87-?in Pontiac: '85-'89

I believe that is correct on the years but the 9 bolt has 27 spline axels.

drain89 has a great write up on 9 bolts...lots of info and tricks

82-90 had 10 bolts with 26 spine axles
90-92 had 10 bolts had 28 spline axles
85-90 firebird 9 bolt
87-90 camaro 9 bolt

90 was a grey year for the 9 bolt and the 28 spline axles

Yea i was just curious because I ran into a weird problem where I thought my rearend was out a 99, and I couldnt find a pinion seal that would fit for the life of me, between the 2 that the guys at GM were telling me were for the car and taking the old seal and trying to match it up was just very aggrivating... but i ended up scratching the dirt of the axle tube and found the casting numbers gave those to the guy at gm dealer and found out I needed a rear pinion seal for a 1990 camaro rear end. Now if what you are saying that the rear ends didnt become larger until 93? why was this rear end about 3" wider than the old one i took out? And I'm not sure why the guy i bought it off of told me he took it out of a 99Z28 and now the casting numbers are telling me its a 1990 rear, probably lied to me haha, but anywase I ended up just buying a new yolk and seal for the rear.

3" wider would be right, for a 4th gen axle (a '99).

Who decoded the axle for you? The stealership guy? Did you tell him what car it was in? He coulda just assumed incorrectly & told you a 3rd gen year, if he newer actually looked it up or couldn't find it in his computer.

The guy i talked to is very knowledgable so it wouldn't have been a mistake by him, i mean neither of the 2 pinion seals would fit the rear, one was to small the other to big. So thats when he said get the numbers off the axle and he looked it up. So he orded me the pinion seal for the 1990 rear end and it was exactly the same as the old one taken off. But why its 3" wider, and casting numbers say its a 90' i have no idea? I believe the numbers/letters he needed were "9HF" if i remember right.. i did this a few days ago, and it just has been puzzling me since.

anyone able to tell me my rear end for my 1987 Camaro. My pig cover bolts count 10, but from one mechanic he said it was 7.5" than another said it was a 7.625"...is there any way i can positive to know exactly what rear end it is? this is the first time I've fooled with this so im not sure how to go about finding out, i was hoping a GM delearship would be able to tell me

87 would be 7.6 (if it's original to the car). The following 10-bolt FAQ will provide all the info you need:

http://www.thirdgen.org/techboard/tr...-10-bolts.html (FAQ About 10-Bolts)

JamesC

The parts will interchange from the 7.5 and 7.6. All new parts are 7.6, but fit the 7.5 diff.