37hemidodge

So here we go . 8.8 373 gears. 28 spline 2000 gt. It looks like the gear that is tied to the drive shaft yoke came in contact with the posi unit & she f*#%+ mangled it . Cracked posi unit and sheared some teeth also. :. So now I would like to get some input on what would be the best route ? Bone yard rear or replace the whole assembly (gears &posi unit) in the existing rear end ? Never replaced gears in a rear before so just not sure looking for opinion's thanks for you guidance.

dawson1112

It sounds like what happened was who ever installed the 3.73 gears reused the crush collar on the pinion. Rookie mistake. The pinion bearing preload can not be set to specs and the pinion nut loosens up over time. The pinion gear walked itself back into the carrier. As long as the gear housing itself is not damaged in any way, you should be able to get a used carrier from the junk yard, and install a new set of gears.

Be extremely thorough in you examination of the gear housing, especially around the collar that the pinion bearings ride in. And in the area where the carrier bearings sit.

If you have never installed gears in a rear differential I strongly suggest you enlist the help of someone who has experience in this. Or at the very least read the install procedure very carefully , reread it several times until you fully understand the proper procedure.

Buy a new gear set or use the gear set that comes with the used carrier. If I was doing it I would use a new 3.73 gear set, along with an install kit. Go with ford racing gears as they are the closest to oem tolerance on the machined portions of the pinion. I also suggest you go to a parts store and purchase a couple extra crush sleeves in case you go to far on the first attempt at setting the pinion bearing preload .

http://cdn.lrsstatic.com/downloads/i...ns/M420988.pdf
Read this completely through until you understand what you are doing, use the proper tools , and do not guess at any thing. Note the factory tolerances for bearing preload, back lash, and proper gear mesh pattern. Failure to get these correct will result in premature wear or catastrophic failure.

37hemidodge

Thanks Dawson ! My 1st thought was a poor installation . I will remove all the parts and as you said check for damage in the housing . The posi unit is cracked also it took a good hit.

Tried to load a pic but no can do

dawson1112

The posi unit is what I am referring to as the carrier. This is what happens when the pinion nut gets loose and/or the pinion bearings completely fail .


I am assuming that yours looks very similar to this.

37hemidodge

Holly crap you high jacked my phone pic ?
It is identical just my sons carrier is cracked in half . You think the housing machine work where the pinion sits on the front may be damaged as well ?
Thanks a lot .

dawson1112

As long as the pinion bearing cups are in place and not all beat up it should be fine.

uberstang1

Rebuild with an 04 cobra diff, 31 spline axles, gear set, and a new bearing and seal kit and be done.