GM 8.5 10 BOLT REAR END POSI

[AUTOTECH7]

I HAVE A 1983 OLD CUTLASS AND HAD DROPPED IN A REAR END FROM A 1985 GRAND NATIONAL. WAS TOLD BY THE SELLER THAT IT WAS RECENTLY REBUILT W/ 4.10 RICHMOND GEARS AND WAS A POSI. CRACKED OPEN THE COVER AND FOUND WHAT LOOKED LIKE A POSI SET-UP. NOW HERE'S WHERE IT GETS FUN. WANT TO CONVERT REAR DRUMS TO DISC. GO TO UNBOLT THE AXLES FROM THE POSI UNIT AND CANT SEEM TO FIND ANY BOLD, PIN OR ANYTHING THAT RESEMBLES A LOCKING MECHANISM. HEAR ARE SOME PICS TO GO BY. ANY IDEA HOW TO GET AXLES OUT? BY THE WAY THE DRUM BACKING PLATE IS HELD IN BY 4 BOLTS. ANY AND ALL HELP IS GREATLY APPRECIATED

 

[85 Cutlass Brougham]

Please turn your caps lock off. It's seen as shouting.

As for the question, If no one else posts an answer, I will look it up in the factory service manual when I wake up (5:10am now). It certainly is odd looking for a posi, do the axles both spin in the same direction or opposite when you rotate them manually?

 

[AUTOTECH7]

Sorry about the caps lock, didn't mean to. Yes both axles turn in the same direction and is pretty tough to turn the wheels in the opposite directions. Again all help is greatly appreciated, thanks

 

[1985Diablo]

click this link

http://1967-81camarocarparts.com/catalo ... brakes.pdf

Go to page 24, you need to remove the C clips, # 36 in the diagram. The axels will then slide out.

Also check this

http://www.chevyhiperformance.com/tech/ ... index.html

Hope that helps

 

[megaladon6]

i'm not too familiar with the innards of a cone style posi so it could be that, or it could be a tru-trac helical style rear. except for the fact that both tires go in the same direction i'd say it looks like a standard open diff.
the other weird thing is the 4 bolts on the axle tubes. G-bodies have a unique 3 bolt flange. that looks like a standard GM tube.
anyway, to pull the axles you have to rotate the diff over till you find the bolt. the bolt holds in the center pin that the spider gears ride on. IIRC you pull the bolt, slide the pin out of the way and then you can see the c-clip. just don't rotate the diff without the bolt in or the spider gears can pop out.
unfortunately it's one of those things i can do, but can't describe.

 

[AUTOTECH7]

I looked at the link and I know that a conventional rear end has those c-clips: after you remove the 5/16 bolt and slide the pin out, you can push the axles in and thus releasing the c-clips...But here lies the problem. There is no 5/16 bolt anywhere to be found and thats where I'm stuck. Also, as the 1st pic is a little hard to tell, there is some solid piece at the center of the spider gears that looks to hold 4 small spider gears ( picture a u-joint and at the ends is where the gears are riding on) and the 2 on the side where the axles slide into. I had someone tell me that I'm going to need a hub puller and yank it out because its pressed to a bearing behind the end seal. How true is this? Just a little back ground, I've worked in the auto field for close to 8 yrs and have never came across anything like this. I know that normal GN's have either a Eaton or Auburn posi/limited slip set ups but this is beyond me. Thanks again for all your info and input on this. I know that this wasn't born there, it has to come out somehow

 

[Blake442]

...the other weird thing is the 4 bolts on the axle tubes. G-bodies have a unique 3 bolt flange. that looks like a standard GM tube...

Did somebody weld on C-clip eliminators?
That'd be my guess...
If that's the case, undo the four bolts and the axles should be able to be removed.

 

[AUTOTECH7]

No there isn't any c-clip eliminator set up. Its all stock and the 4 bolts that are on the ends only hold the drum backing plate and seal dust cover.

 

[shotgun]

Looks like a stock BOP Abody rear to me.

The bearings are pressed on the axles.

You can just remove the bolts and slide out the axles.


Edit: measure from backing plate to backing plate to help figure out what it is. Did you remove it from a Gbody?

Compare the width to your stock housing.

Like I said above looks like a early rear. It has 4 spiders which is a good thing, they made them with 2 spider gears also.

 

[AUTOTECH7]

I can tell you of hand that i compared this diff with the original one that I pulled out and they're about the same size, give or take a 1/8". And also the control arms went together without any modification as did the shocks.