I was able to install the ring and pinion in the front axle on Saturday. Took all day Saturday!
Some highlights:
Setting up the pinion height was fairly easy. I had 2 factory shim stacks for a "+3" pinion head. Both stacks were exactly the same. I was also able to measure the pinion depth once I had it installed in the housing, measured exactly 2.25" from the axle center line as per the FSM.
The pinion bearing preload was fairly easy to set. Just a matter of adding or subtracting shims to get the correct preload. Took me about 5 attempts. It takes approximately 40-45 inch pounds to keep the pinion rotating once it has already started rotating. The FSM calls for 20-50 inch pounds, so I am happy with this setting, especially with new bearings. NOTE - I said to "keep it rotating" once it has started rotating. The torque to get the pinion initially turning is slightly higher then the rotational torque, as it should be.
Setting up the carrier (carrier bearing preload and ring/pinion backlash/contact pattern was more fun. This took me about 30 attempts. I had no problem eliminating all carrier side play by shimming each side, and no problem adding the preload shims to slightly preload the bearings. I did have some issues getting the back lash right. This took most of the time, moving .001 and .002 thick shims from one side of the carrier to the other to get the correct backlash. FSM calls for .005-.010 on the backlash, I am at approximately .006-.007.
The one thing I could not achieve was a "perfect" contact pattern. This really bugged me. I reinstalled the carrier multiple times, slightly changed backlash settings, and never could get a "perfect" pattern. But, then I realized I am setting up used gears with some wear. That, and these gears were not set up correctly in the old axle. When I finally settled on my backlash and went back and checked the pattern, the teeth are meshing correctly (center of the tooth, centered between the "heel and toe"). But, they do not mesh so tight (like new gears would) to remove the paint off the ring gear. The contact pattern I have does "smear" the paint good, and considering the wear on the ring and pinion gears, I think this is as good as I can get it. With my.006 backlash, i do not want to set the gears any tighter. I think I have the pattern as good as it is going to get. With a new ring and pinion, I am confident i could get the pattern dead on.
Few pictures:
The installed carrier, with dial indicator attached to check final backlash.
Blurry picture of the dial indicator's face, showing .006 backlash between the ring and pinion teeth.
Close up of the ring gear. Note the existing wear pattern, which is slightly closer to the "heel" of the teeth. My install has the contact pattern centered. This existing wear is what was making me pull my hair out trying to get a "perfect" contact pattern.
All in all, this was a very educational experience. I will probably try to set up at least one new ring and pinion set up in the future. I think with new gears, I could get the set up dead on. But, this is not something I want to do all the time. Just this front axle took me all of Friday night and all day Saturday to get set up. I am happy with this current set up in the front axle of this jeep. If this was the rear axle, I would install a new ring an pinion to get a more "perfect" pattern. But, it does not make sense to spend money on a new 3.31 gear set for the front axle. Once this jeep gets back to JeepAddict, he might decide to install lower R+P gears front and rear to get better big tire performance. For now, this set up will work fine.
That's it for now.
for the attempt! Just curious if playing with the pinion might have done the trick.
I think the only issue we might have with it is that it could be a little "noisier" then a new gear set, mainly due to the existing wear on the ring and pinion teeth. Worse case, will have to install a new ring and pinion if this one starts prematurely wearing out. If that is the case, time to change ratio's anyway
