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Posted by: VEEMAN Jul 11 2013, 07:15 AM

I need a little help wth the R&P pattern I have on my 71 901 dog leg gearbox. As you can see in the attached photo's the pattern I'm getting. Have added a second post with other photo.
I wish to know from any one with knowledge of these patterns, if my patterns are correct?
Can I run this box? or what adjustment do you recommend to set it up right.
Any advice please.
Thanks
Veeman

Posted by: VEEMAN Jul 11 2013, 07:18 AM

Second photo to go with above post.
Cheers
Veeman

Posted by: pcar916 Jul 11 2013, 07:35 AM

With that amount of wear did you measure the R&P backlash (at the flange) before taking it apart? With the pattern worn that deep into the forward load side I wouldn't change a thing if the backlash was in spec.

It's scrubbed across nearly the entire tooth, which is good on a hypoid gear. If you change it, depending on which direction you move it, the pinion might start wearing into the unworn area.

In that case you'll get lots of noise, heat, and hyper-wear IMHO, perhaps a broken pinion tooth or two. If this is a high hp car I'd replace the R&P.

If it's stock... I'd probably replace it anyway, but if you put it back together it'll still work. Just don't change the shims & spacers.

Lot's of metal in your magnet?

Posted by: VEEMAN Jul 11 2013, 12:07 PM

QUOTE(pcar916 @ Jul 11 2013, 05:35 AM)

Posted by: Mark Henry Jul 11 2013, 01:10 PM

Is that a ridge worn right in?

If it is then that is the R&P is junk and yes run it till it fails, but be on the hunt for a replacement box.

Evil had a cool tool for setting up R&P's, but I bet you could figure a way of coating the R&P in dykim blue and looking at wear patterns to figure it out.

Posted by: pcar916 Jul 11 2013, 02:07 PM

If it was in pieces, unless you know the gasket measurements and the diff still has the bearing installed it's scrap 'cause you'll never get it back together right. To get the proper backlash, you'd hit that ridge and it'll not last even with a stock engine.

I'd get another trans, or carefully inspect and verify the one you have has other good parts and replace the R&P. Frankly seeing that wear, I'd bet there are other badly worn parts... looks to me like it was run low on lube for a long time. But that's just me speculating.

Mark's spot-on about getting a good mesh pattern with trial and error and Dykem Blue. It's a process that requires strict attention to detail to set up the preload, offset, pinion depth, in addition to good record-keeping, and likely a few other spacers/shims. Might not, but probably will.

It's fun if you're mechanically inclined and you have really good sharp tools.

Posted by: messix Jul 11 2013, 02:18 PM

what ridge are you guys seeing?

I see where the grease has displaced out to the base of the gear.

clean the gears and use a little bit of white grease dabbed on a couple of teeth and see where that puts the pattern at.

you should be able to get it reasonable and the diff might make some noise compared to a virgin or brand new set but it would be useable and last for quite a while.

Posted by: sixnotfour Jul 11 2013, 02:45 PM

http://www2.dana.com/pdf/5717.pdf

Posted by: pcar916 Jul 11 2013, 03:21 PM

If that's Dykem (it is rather blue after all) rather than a metal ridge that's a whole different story... a much better one.

Posted by: VEEMAN Jul 12 2013, 06:50 AM

The stuff I used to mark the diff with, is known as engineering blue over here in the UK.
Where is the gearbox guru gone on this forum?
How can I tell a good second hand diff if it is out of the gearbox?
I could just be buying another basket case, and back to square one.
Delemas!!!!!
Veeman

Posted by: Dr Evil Jul 12 2013, 10:22 AM

Unfortunately, without the proper special tool to set the diff, you are just guessing. Matching the pattern as best you can is your only bet. Any fine tuning after that was merely done to decrease noise. Perhaps you should have fun with this one, experiment, see if you can get it right and only if not, then get another gear box.