The Stovebolt Site Forums The Shop Area Driveline Ring/Pinion Contact Pattern Check-Tips

I am in the process of installing new 3.55 ring/pinion gears from one of the vendors into the rear end of a 1949 chevy 1/2 ton.

I am at the point of checking the gear contact pattern. I have 0.030" shims installed and have 0.005" backlash.

Can I get some feedback on this contact pattern and what next adjustments to the backlash or shims I should make? I am not sure how I should proceed. Pictures are at this link:

http://s1285.photobucket.com/user/1866yellowboy/library/Ring%20and%20Pinion%2025%20Thou%20Shim

The dark black mark towards the bottom of the of the gear tooth is the coating on the gear tooth. The entire ring gear was this color when starting and has worn off in the area above it as I have been changing shims and checking contact patterns. I have incorrectly labeled the photobucket album (the pictures are with 30 thou shims not 25 thou) but they are the correct pictures.

Thanks in advance!

Your contact pattern looks to be good - similar to (the pattern in the upper right illustration).

Looks very good! Torque it up and get that rig on the road!
Jerry

Is that yellow ochre grease paint?
Carl

If you had a load on the ring gear while turning the pinion gear, then it looks very good. You can get a false pattern if you just rotate the gears with holding back on one or the other.

Joe

Thanks for all the feedback. After seeing the price of the 3.55 gears and reading on various forums that the gears were gonna chip or burn up if I got it wrong (most were surely extreme and exaggerated cases) I wanted to get some opinions from someone who has done this before.

I did load the ring gear by putting a pry bar between the differential case and the housing and turned the pinion which was a two person job for me with the enclosed drive shaft.

I used the GM gear marking compound which I got from amazon for 12 bucks w/ free shipping. The 1 oz tube did not sound like much to me but it is way more than I will ever use in my lifetime. I didn't put a dent in the tube with this job and I did many iterations.

You did good, it should run a long quite life.

Joe

I've got a little over half a can of Dutch Boy white lead paste that I mix with linseed oil as a gear pattern indicator and also as lubricant for the dead centers I use on a couple of lathes. That's at least a 5 lifetimes' supply for me!
Jerry