Adding / upgrading a posi unit to the 8.5"

[S10xGN]

Hi All,

I'm in the process of buying a non-posi 8.5" GN rear for my son's 383" MCSS. What are people recommending for aftermarket posi units? I've got an estimate from Pyle Bros in Baytown for *about* $590 for a new Eaton unit installed. Are there any cheaper units available or should we stick with their recommendation?

Thanks!

 

[WarpSpeed]

An Eaton will work fine. 590$ seems alittle high You can pick one up for *about* $300. It's not hard to install, really.
I run an Auburn, and it works fine too, about the same price.

 

[MBR87GN]

Just had an eaton installed.540$ out the door installed w/new bearings and seals.

 

[Red Regal T]

Just saw the eaton in Summit for $429 w/ shipping figure $440. You'll need bearing installed, figure another $50. As far as installing it, that only requires changeing the ring gear from the old unit to new and shove it in. No need to re-set gears. I guess whatever you feel comfortable with.

 

[S10xGN]

This was from Pyle's:

we would suggest an eaton for the application. if all you did was install the carrier the labor is 125, carrier 399, special bearings and races for the carrier 35, shims oil and additive 30. we stock the parts.

So John, are you saying all I need to do is swap the carrier, no setting backlash or anything? Are there shims on the side bearings that need to be maintained? I'd prefer doing it myself, but am not sure I'm "qualified" for such an undertaking. I'm looking for Eaton prices right now...

Thanks!

 

[Red Regal T]

Yes, that's pretty much it. You have to maintain the shims in the same position and install the carrier and torque the caps. New carriers don't come with bearings, so you'll have to buy those and have them pressed on. I got a posi from the boneyard a couple years ago. I had to install a ring gear spacer. I did so and then shoved it in. It's been good for two years of abuse. I'm no expert but my installation worked fine. If you want, post a question for installation and see what info you can come up with.

 

[Doug Jacobson]

The Eaton Posi will use bigger bearings than the stock ones. This will put the bearings on both sides farther 'out' you will not be able to use the stock shims. You will need to but a shim set, set the pre-load then transfer shims to get the backlash you want.

 

[Benched]

I just recently priced posi conversions in my area. One was $805 for an Eaton with new bearings, and the other was $850 for an Auburn with bearings.

I ended up buying an Eaton off of E-bay and a master rebuild kit for <$400, so will be doing it myself.

I have found three sources for information on the mechanical end. The GM manual, gnttype.org., and www.differentials.com.

 

[captrob]

Search the archives

http://www.gnttype.org/techarea/suspension/posi.html
http://www.gnttype.org/techarea/suspension/axleremoval.html
Went really easy. Bought everything (Posi-unit, new berings/races, and new axel berings and seals) from http://www.gearsareus.com .
Wayne has a GN and knows exactly what you need. The Eaton was $349, berings $30, axel berings/seals $15 I think. Plus $20 shipping.
I was able to re-use the stock shims. Just be carefull not to break them with the BFH!

Follow the links above and it is a piece of cake.
HTH, CaptRob

 

[Kid with a toy]

Hey Russ,
What time ya want me over there?
I'm back to the non-working class again, so time is no longer a question.

Erik

 

[S10xGN]

Erik, that didn't last long! WTF happened?

Have any of ya'll got any experience with the Lockright Powertrax drop-in units? These are around $400 and slide right into the stock open carrier.

Thanks!

 

[Kid with a toy]

Hey bro,
from what I've heard, the Eaton is subosed to be a drop in. Worse case, head over to the Monte board and buy a used unit, or hell, one off of this board. Let me know when ya plan on doin it. I seem to learn best from you, Joel, and Chris...when it's not my car.

Update......
The valve train has been replaced...beefed up everything.
The BGC IC bracket has been redone.
New flip down plate for the rear plate is in place at the rear plate.
And the Mease DP (that I should show you before I put it on the car) should go on soon.
Along with the new (used) torque convertor.

Just in time for the 11th St. Drag.

Erik