Comments on ring and pinion mesh pattern
 

I'm trying to set up R&P in an early 901 transmission, and would like comments on the mesh patterns. The pinion depth is set to the spec engraved on the parts, and the backlash is .12mm, which is the minimum per the workshop manual.

I think the drive side looks OK, but the possibly coast side is too close to the nose and heel of the tooth?

Knowledgeable observations welcome and appreciated!

http://forums.pelicanparts.com/uploa...1541292295.jpg
http://forums.pelicanparts.com/uploa...1541292295.jpg
http://forums.pelicanparts.com/uploa...1541292295.jpg
http://forums.pelicanparts.com/uploa...1541292295.jpg

I did see that diagram in another thread, but it leaves a question about what the coast side should look like. I have also seen reference to the coast side being more important when looking at mesh patterns on used gears.

I also found this online:
http://forums.pelicanparts.com/uploa...1541360375.jpg

To my eye, my pattern most resembles the 3rd from the left in the middle row, but I'd still like some feedback...

i'd agree with your pattern looking like the third from the left in the middle.

How or were you able to put some sort of load on the diff while doing your check? On a traditional car you can have someone just ride the brakes a bit.

There is a bit of a black art to this and suggestions are all over the place. Some say they want to see the drive pattern in the middle some at 1/3 from the bottom. As when there is a load applied the pattern with spread up.

It would be nice if one of the gear gurus would chime in on this. I'd be interested in hearing other peoples opinions as well.

I don't use blueing or any other marking medium for a number of reasons that have been discussed before in this forum. If the pinion depth has been set properly with one of the factory tools, and the backlash is within spec, you should be fine under load.

That said as a caveat, you photos look to my eyes to be consistent with backlash on the low side. You might try increasing the backlash a little. Cheers,

Thank you for the input. I tried many iterations, and ended up with the following, which had the pinion slightly deeper, and with backlash on the high end of the range. This was as good as I could get it. I will find out how it sounds in the next month or two...
http://forums.pelicanparts.com/uploa...1541820560.jpg
http://forums.pelicanparts.com/uploa...1541820560.jpg

Here are some pics from my recent ring & pinion swap:
http://forums.pelicanparts.com/uploa...1541824763.jpg
http://forums.pelicanparts.com/uploa...1541824763.jpg
http://forums.pelicanparts.com/uploa...1541824763.jpg