8 1/4 open to posi

[leblanc]

I just bought an 8 1/4 non-posi. My plan is to change this to a 3.91 posi. Should I change the axle seals or anything else before I go too far?

 

[SGBARRACUDA]

I just bought an 8 1/4 non-posi. My plan is to change this to a 3.91 posi. Should I change the axle seals or anything else before I go too far?

When you tear it down to add the 3.91 and SG would be the time ti replace the axle seals or bearings if they need them and the pinion seal or pinion bearings and diff bearings. Also check brakes,and wheel cylinders, brake hose etc. Do it right the first time and save many headaches later.

 

[sweatybetty]

sure grip, sure grip, sure grip!!

 

[superdart]

I would recommend welding up the axle tubes, and studding the carrier caps.

It also wouldn't hurt to put on a diff girdle cover if you want the extra strength.

For added durability I am using a late model (97-up) 8 1/4 Sure grip, as they are 29 spline instead of the older 27 spline design. The down side is this requires aftermarket custom axles ($235 from Moser).

 

[rumblefish360]

SuperDart, thats actually a good idea. That 97 and up sure grip is a bolt in right? I think it is. But the added cost of Moser axles and the above strengthening ideas are really good ones.

When I did my 8-1/4 for the Duster project, the bearings were/er/ are in good shape. But I did re-do all the brake parts new with new lines and wheel cylinders. New gear oil and additive. Etc....
Scraped the dirt off and preped it for paint.

Below is the result of taking a little time. So worth it in the end.