Slant Six Forum
https://www.slantsix.org/forum/

Putting a posi unit in an 8 3/4
https://www.slantsix.org/forum/viewtopic.php?t=87		 Page 1 of 1
Author:  Mike Andreas [ Tue Oct 29, 2002 4:52 pm ]
Post subject:  Putting a posi unit in an 8 3/4
Hi guys,

I have an a-body 8 3/4 w/3.23 gears (from Lou) and a posi chunk from another source.

My question is - How hard is it to install the posi unit myself. I have a shop manual. It doesn't look too bad but before I take the thing apart I thought I'd ask.

Mike
Author:  Doctor Dodge [ Tue Oct 29, 2002 10:39 pm ]
Post subject:  Posi swap is pretty easy...
You can swap-in a posi carrier without much trouble.
You should have a "spanner wrench" and a dial indictor.

Check the backlash and ring gear run-out reading with the dial indicator, before removing the carrier. (write this info down)

Mark the caps and adjuster rings on one side of the case. (they need to stay on the correct side.

Remove the ring gear carrier and then remove the ring gear from the carrier. Note that these are left hand threads. Also note that Mopar used 2 different types of bolts to hold the ring gear onto the carrier so keep the ring gear bolts with the carrier they came from. (straight shank vs. tapered)

Inspect the ring gear and carrier surface for nicks, burrs etc. I use a stone to make sure it is flat. Inspect the carrier bearings and races, replace if needed.

I clean the parts and heat the ring gear in a toaster oven. The hot gear will drop onto the carrier and allow a short moment to align the bolt holes, work fast.

Back-off the spanner (adjuster) nuts if they are still in the caps, re-install the carrier and snug the cap bolts. ( do not torque yet)

Adjust the spanner nuts so the backlash is close but loose. torque one side of the caps.

Follow the final backlash, carrier bearing pre-load procedure in the FSM. Note that used bearings use about 1/3 of the pre-load needed for a new bearing. If you re use bearings, keep the pre-load light.

Get the backlash and run-out back to the setting you found them. (run-out can be better (less) but do not go less on the backlash. Finish torque the caps.

Check the tooth contact pattern and adjust the backlash if needed for a better contact pattern.
DD
Page 1 of 1 All times are UTC-08:00
Powered by phpBB® Forum Software © phpBB Limited
https://www.phpbb.com/