1969 Buick Skylark 12 bolt rear end.

[plumbbob]

How hard is this to put a locking differential in. It si a 12 bolt rear end and where would I look..Thank you

[raycow]

The actual disassembly and reassembly aren't difficult, but there are a couple of finicky adjustments you need to get right. One is the side bearing pre-load and the other is the gear backlash. If you have not done this before, I strongly suggest that you get a shop manual and read the rear end section thoroughly before proceeding with the job.

If you aren't changing gearsets, the good news is that you won't have to set the pinion depth.

Ray

[plumbbob]

How hard is this to put a locking differential in. It is a 12 bolt rear end and where would I look..Thank you

I'm having trouble finding a locking differential for this rear end and how strong will it be if or when I do.

[raycow]

I'm having trouble finding a locking differential for this rear end and how strong will it be if or when I do.

Well, I was kind of wondering what kind of rear you have in there, because I wasn't aware that Buick had made a 12 bolt for the A-body.

The likely possibilities are:

1, It is a Type O rear, which is Olds, originally made for the 442, and would be a bolt-in swap.

2. It is a Chevelle 12 bolt, also a bolt-in swap.

3. It really is a Buick rear, like used in their big cars. This would have to be a dedicated A-body version, because the big car rear won't bolt up to the A-body suspension.

You can get almost anything you want for the Chevy rear.

There is limited aftermarket support for the Olds rear. You can get a posi for it, but I am not sure about a real locker.
http://www.ebay.com/itm/Posi-for-8-5...item19ccee1bbc

This link has a post about a true-trac, which might be an acceptable alternative.
http://forum.jdrace.com/viewtopic.php?f=17&t=318

The big Buick rear was available with factory posi, but I am not aware of any aftermarket support for it because these were not considered to be performance cars.

Foe identification purposes, the Buick and Olds rears have pressed on axle shaft bearings and the Chevy rear has C-clip shafts.

If you don't know which type of rear you have, could you post a pic of it?

Ray

[cjp69]

I'm having trouble finding a locking differential for this rear end and how strong will it be if or when I do.

Jim at JD Race and Restoration is widely considered the expert on Buick rear ends.

http://www.jdrace.com/contact/contact.htm

He also goes by "monzaz" on several message boards.

[bobc455]

How hard is this to put a locking differential in. It si a 12 bolt rear end and where would I look..Thank you

Locking? Or Positraction?

-Bob C.

[raycow]

If anyone knows, please tell me what kind of 12 bolt rear would have come STOCK in a 69 skylark. Was it a Chevy 12 bolt, an Olds 12 bolt (actually a 10 bolt with a 12 bolt cover, or something else entirely different?

Ray

[cjp69]

If anyone knows, please tell me what kind of 12 bolt rear would have come STOCK in a 69 skylark. Was it a Chevy 12 bolt, an Olds 12 bolt (actually a 10 bolt with a 12 bolt cover, or something else entirely different?

Ray

Ray,

The Canadian built 69 Skylark's came stock with a 12 bolt.

[bobc455]

Canadian-built Skylarks has a Chevy 12-bolt. Ratio varied, and I don't think any of these are Posi-Traction. I believe these were the same setup as you'd find in Chevelles from the same plant.

American-built Skylarks and GS's has a 10-bolt. I think there were the 8.2" and 8.5" sizes.

All of them are pretty stout - I've heard of a lot of HP going through the 8.5" rearends. Parts for the 8.2" are hard to come by.

-Bob C.

[raycow]

Thank you Bob. So does that mean that plumbob's car is Canadian (assuming that his 12 bolt rear is original to the car)?

If yes, then it looks like his posi and locker possibilities just got a whole lot better.

Ray