Gear pattern help

[Melissa_F]

I am thinking i need more in my pinion shim. 0.010 backlash. Ford 7.5 rear. This is my second gear setup, so i'd like to hear some feedback from the experts. Thanks.

http://s482.photobucket.com/user/crshdummy/library/Mobile%20Uploads

 

[imp]

More what?? Have you a Ford Shop Manual? The images are too small to interpret.

Most important things about setting up gears are these:

1. Pinion bearing preload
2. Ring gear bearing preload
3. Drive tooth contact pattern,
4. Acceptable backlash (clearance) between gear teeth

Once these important things are met as acceptable, manually rotating the gears while placing resistance on the pinion (input) with say a rag about it, in other words, turning the gears with resistance placed on them, the movement should feel smooth, no scraping feeling or sound produced. If smoothness of rotation is felt, the gears will run nice and quiet. imp

 

[Melissa_F]

Did you try clicking on the images? They go full size that way.

More in the pinion shim = a thicker pinion shim.

 

[FR-425]

Pinion shims set the depth, carrier side shims set backlash.

 

[SoHK_alumni]

I'm far from an expert, but I'll agree, looks like there's not quite enough shim under the pinion gear.

Contact area seems too close to the top of the lands. It's well centered between the toe and heel, but not deep enough into the groove.

Moving the pinion inwards will also mean the ring gear will need to be moved over -- always the chase when setting up a diff.

 

[imp]

Did you try clicking on the images? They go full size that way.

More in the pinion shim = a thicker pinion shim.

I did. My computer would only expand the left image, the coast side. Both coast and drive appear located a bit inward toward the inside diameter. This is not a bad thing. Most important is whether the gears "feel" smooth when rotated by hand while applying restraining torque, given that BOTH pinion bearing and differential carrier bearing PRELOAD is acceptable.

Understand, please, that contact pattern is not exactly "gospel". When the gears are actually working under load the ENTIRE faces of the teeth come into contact, not just the little blobs seen with color. imp

 

[Melissa_F]

I've increased the pinion shim and posted the results. Same link as original post. The first two are the increased pinion shim thickness, the second two are the original thickness. The drive side looks better with a thicker shim, although the coast side doesn't look as good as the original.

 

[SoHK_alumni]

I think that it is 1st, a much better contact pattern and 2nd, certainly acceptable.

 

[Melissa_F]

I was considering putting another 0.005 in the shim for a total of 0.010 over original. To see if it would push it more towards the center. I don't know if it is worth the effort though.