12 Bolt Questions...

[fahrenschnell]

Another Dumb Question....

Are the internals of a truck 12 bolt the same as a car 12 bolt?

Did the 12 Bolt internals change drastically over the years?

I have a 12 Bolt from the early 70's and it has an open diff....Can I swap in a limited slip or Posi from a late model truck? Just Curious...

Seth

[Caddyman]

Re: 12 Bolt Questions...

No.

Car and truck are different.

Car 12 bolts are all the same....remember, they actually only used them a few years.......

Truck 12-bolts had a few differences over the years, but most stuff is interchangable.

[fahrenschnell]

Re: 12 Bolt Questions...

Crap....That is what I thought.

I really don't want to spend $300 bucks on a posi....

I guess I will have to start the Junkyard Crawl...

Seth

[Loren]

Re: 12 Bolt Questions...

Good luck finding one in a junkyard anymore.

Notable (and relatively minor) internal differences in car 12-bolts are different ring gear lateral positioning for numerically high gears from the factory (you are unlikely to encounter this) and two sizes of outer axle bearings (full size cars are larger than Chevelles, Camaros etc). GM would have made it a lot easier for us if they'd made truck 12-bolts the same as in cars, one of the few areas where Ford had the edge in interchangability with the 9".

[squirrel]

Re: 12 Bolt Questions...

truck 12 bolt has a smaller pinion bearing, which is the main difference, along with the lateral spacing difference. I thought I heard that certain offset truck and car diffs can be swapped with some creative shimming, but please don't hold me to it.

[Huskinhano]

Re: 12 Bolt Questions...

No.



Car 12 bolts are all the same....

I know we're talking about Chevy axles in this post but IIRC the BOP 12 bolts are different then Chevy 12 bolt.

[Bamfster]

Re: 12 Bolt Questions...

No.



Car 12 bolts are all the same....

I know we're talking about Chevy axles in this post but IIRC the BOP 12 bolts are different then Chevy 12 bolt.

Thats what I thought too....

[Mr4Speed]

Re: 12 Bolt Questions...

No.



Car 12 bolts are all the same....

I know we're talking about Chevy axles in this post but IIRC the BOP 12 bolts are different then Chevy 12 bolt.

I have a BOP 12 bolt and they are completely different than Chevy 12 bolts.

[badass475olds]

Re: 12 Bolt Questions...

No.



Car 12 bolts are all the same....

I know we're talking about Chevy axles in this post but IIRC the BOP 12 bolts are different then Chevy 12 bolt.

I have a BOP 12 bolt and they are completely different than Chevy 12 bolts.

An Olds 12 bolt actually only has 10 bolts on the ring gear. But 12 on the cover, The ring gear is a smaller DIA, the axles though are not heald in with C clips , they have a backing plate on the ends of the tubes.

[SpiderGearsMan]

Re: 12 Bolt Questions...

after doing blown axle seals and bearings on jeep rears nearly every day
it makes me appreciate the simplicity of c clip gm axles

[CTX-SLPR]

Re: 12 Bolt Questions...

after doing blown axle seals and bearings on jeep rears nearly every day
it makes me appreciate the simplicity of c clip gm axles

After helping a friend get his Nova off of sitting with the tires under the quarters I like positive retension axles.

[min301]

Re: 12 Bolt Questions...

Yeah, I'll take the extra labor, much safer.