Gear Mesh between bevel pinion and ring gear

McCormick-Deering 22-36 Project.

Transmission almost put back together after replacing four tapered roller bearings and the spline shaft hub, and making some custom chrome-cobalt castings to take up the wear on the spline shaft, using these 6 shims between the hub and the spline shaft to successfully take up the slack.
Before completing the rebuild, I decided to test the gear mesh, without the entire weight of the tranny to contend with.
I put the tranny back into the frame, fitting the two tapered orientation pins, one on each side, also using the proper thickness gasket material under the tranny where it meets the frame, then bolting the tranny down.

I painted two teeth on the ring gear with marker paste and then ran the gears together, back and forth 30 times or more and all the way around several times.

The following image shows the gear mesh pattern.
Without giving my opinions, which I have, I would like to have your feedback on what conclusions to draw and what to do.

Thanks,

Tom


<a href="http://s99.photobucket.com/albums/l281/Tom_084/?action=view&current=Gearmeshpattern1forposting.jpg" target="_blank"> </a>

If the ring gear backlash is in the area of .007 to .009, I would run it as is. Straight Bevel gears can be adjusted in and out to make the wear pattern slightly different, but not much. .003 more extension of the pinion might makes some difference toward the middle due to fatter teeth moving toward thinner teeth, But the pattern is OK to me. Jim

Your teeth are yellow, maybe you need some more time with the dentist

I would sacrifice the gear backlash spec in favor of matching the existing wear pattern. Some extra backlash won't hurt like it would in a highway vehicle where you have a lot of accelerate-coast-de-celerate cycles that can rapidly load and unload both sides of the gear teeth.

If I had NOS parts I would definately follow the book and set things up accordingly. With these 80 year old parts the original tooth profile had changed due to wear. I can see in the photo where the old pattern is. The gears will be a lot happier (and quieter) going back to their old set way.

I'm with Jim on moving the pinion in to at least better center the pattern that you have.

36F30,

The sad thing is that I am a dentist. I should be given 40 lashes with the wet noodle for permitting this kind of thing to happen.
If nothing else, I could have had the common decency to at least use a blue marking medium!!!

The apologetic Tom