Setting the Preload on the Front Diff: 5mt

[Grayguy]

ok, so a while ago I bought a 93' T-leg with a 5mt. The tranny had some issues, and I ended needing to take off the Front Diff Bearing retaining caps (that's what I call them, idk what they really are called) and now I need to know how to properly set the preload on them. Does anyone know how I can do this myself? the dealer wants $200 for it...

Here is a picture of the "tranny issue" and the cap/thing I'm talking about

[wfoote]

Did you have both caps off at the same time? If so, you are setting up more than just pre-load, you are also setting the depth the pinion gear meshses with the ring gear.

What did you do to the transmission? Is it still in the car?

[Grayguy]

No I didn't have both caps off, but I have a feeling they should both probably be reset. I didn't do anything to the thing, I bought it with a supposedly rebuilt tranny, and I got it home, pulled the motor, and found this.

Whoever took it apart failed at life, because the big bearing inside that cap that holds the diff wasn't in there....

[wfoote]

First off if the diff was missing that bearing, I would be really suspicious about what else may have been left out. This is usually setup with the transmission out of the car.

Here is the basic procedure to set the pre-load, but a few of assumptions and a caution first.
1. I am assuming the pinion depth is set correctly, you have some way to turn the pinion gear and the retainer adjustments are being done without o-rings and seals.
2. The caution is if you do this wrong, you will most likely destroy the pinion and or ring gear.

First you need to back the ring gear carrier away from the pinion gear. This is accomplished by turning out the left side LS retainer several turns. Run the right side RS retainer in until there is light resistance felt. ( you are want to be sure the carrier is being supported by the retainer bearings. ) Put one of the stub axles into the carrier and wiggle the carrier. You should be able to feel the carrier teeth "bump" the pinion gear when you wiggle the stub axle.

Setting the depth; hopefully you have a feeling for the bumping I am trying to describe. You want to slowly "move" the carrier to the right until you don't feel any play between the gears. This is accomplished by loosening the RS retainer then tightening the LS retainer an equal amount. Be very careful not to run the carrier in too far. You just want to eliminate all wiggle and nothing more. The RS retainer should only be turned in until light resistance is felt. Make real sure you can freely turn the gears with no binding. You are now at the "zero lash state".

Setting the pre-load; Screw out the LH retainer by three teeth then screw in the RH retainer by three teeth. Tighten the RH retainer by an additional 1.75 teeth.

Verify backlash; The backlash should now be .13-.18mm or .0051-.0071in. If not, each tooth change on the retainer equates to ~.05mm or .0020in.

If all is well, mark the position of the retainer and back out the LH retainer (count the number of turns) now install the seal and o-ring and re-install the LH retainer to the marked position. Repeat for the RH retainer. Install the lock plates and you are done.

Good luck,

[93forestpearl]

Max, who supposedly "rebuilt" it? I'd be worried about the state of everything else inside. Derek could go through it at work for about $400 in labor, but that is in cloud.