posi

[pontiacgp]

yes but a 7.625 carrier has 28 spline axles and your g body 7.5 has 26 spline axles.S-10 have both sizes

the F body 7 5/8 diff did have both 26 and 28 spline axles...and if you wanted to upgrade the axles to the 28 spline you can use the axles from a GN...

* 1982 to 1984: 7.5 inch ring gear, 26 spline axle
* 1985 to 1989: 7.625 inch ring gear, 26 spline axle
* 1990 to 1992: 7.625 inch ring gear, 28 spline axle

 

[v8fieroman2003]

rear axle

im stumped, cause i have a '83 bonaville wagon that aparently was built late '83 and has a lot of '84 parts on it. I know this happens alot, especaly on gm's , (i get that stuff all the time at autozone) but to my knowledge the car should have a 7.5 like everything else but it has the 8.5. now to my understanding this is kind of a rare car anyway, but im wondering if someone goofed at gm or this was suposed to have the same rear as a gn, or the 442. anyone know for sure, cause i cant find anything on this car!!!!!!

 

[pontiacgp]

that bonneville may have come with the infamous diesel engine and I don't know what they put in the rear ends of those cars....if you can find the build sheet on the car that might solve the mystery....

 

[85 Cutlass Brougham]

Look at the data sticker under the rear load floor and see if it has option code G87, which is the GM code for the 8.5 rear axle.If it is G89, it is a 7.5 axle.

 

[87MonteSS]

jack up the axle so both wheels spin freely. Put the car in neutral. Spin one wheel and look at the other. If they spin in the same direction, you have posi.

This is true, unless the rear is an Eaton Locker. Then the only way to tell is to pull the cover.

 

[pontiacgp]

If it's a locker you'd hear a clicking noise going around a corner....

 

[87MonteSS]

If it's a locker you'd hear a clicking noise going around a corner....

Not necessarily true. If it's a PowerTrax unit you will hear the clicking, but an Eaton unit uses a ramp type system to lock the side gears when under load and pre-defined wheel speed is different from left to right. Under normal driving the system functions the same as an open rear.

I have an Eaton locker in my Monte SS and it's completely quiet, even when ramping and locking. The lockup is almost instant and not noticeable at all.

 

[85 Cutlass Brougham]

jack up the axle so both wheels spin freely. Put the car in neutral. Spin one wheel and look at the other. If they spin in the same direction, you have posi.

This is true, unless the rear is an Eaton Locker. Then the only way to tell is to pull the cover.

Do you mean a "Gov Lock"? I don't think GM ever put them in a 8.5 equipped passenger car in the 80's. It wasn't until the 90's that they were used and then only in truck applications if memory serves. Plus, Olds did not use the Gov Lock diff. According to my factory service manual, Olds used either a clutch or cone style posi as there is no information given on the Gov Lock. However, they were used in Chevy and Pontiac applications, such as the MCSS and 3rd gen F bodies. If the Pontiac wagon has a Gov Lock 8.5, it would be a very odd installation indeed! As far as I know, only the Turbo Regals and 442 and Hurst/Olds Cutlasses used the 8.5 from the factory.