Questions about differential

I have started on the R&P setup, not being the most patient customer I already dread that job !! Anyway..

Reading from other forum posts ,making notes and copying with no shame good ideas, I did this, a rig to give more resistance when turning the R&P and improving the marking of the pattern on the teeth.
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So then I started.
I use the original pinion shim of .025 and the pinion preload is quite free like 7 Inch/lbs.
.229 shim on the left and .2385 on the right
Back lash of .006 to .0065 , and this is kind of my first reading.

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And on the another part of the ring
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Now.... I thing that on the drive the contact is not bad, but on the coast I am a bit lost here !! Too low maybe ? Not enough back lash ?

If Gary can join the party, I will be more than happy.
Thanks in advance.
 
That is very interesting to see how you are loading the RG. I made a simple tool that bolts into the yoke and I can apply and vary the loading while patterning.

Whose gears are you using? I didn't go back to see where and what you. 025 shim is thin for GM gears but could be right for aftermarket. Looking at your Crown Gear it appears to be a 2 cut gears, the obvious sign is the teeth are equal in height at the toe and heel. These tend to show a diagonal pattern as apposed to the 5 cut tapered gear pattern of a equal length footprint. If you have 2 cut get the pattern centered on the teeth. You can find more info online about the 2 cuts.
 
Hello Gary,
This R&P is a factory GM, set by a PO and never been used for years, just sat fitted to the car until I opened it up for a check and found no oil in it , hence replacing all bearings and checking the pattern who looked weird to me.
And by comparing your pictures with mine shows a huge difference.
 
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All right ,I understand better about the cut now. This explain the pattern then.
Would you think that having it a bit higher will be better?
 
This is the marking on the ring gear
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Gary, can you please confirm if it is a 2 cut ?
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And after a .0045 back lash. I cannot really move the pattern on the teeth and staying inside the recommended 2 cut BL .
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Tomorrow, I'll fit the new bearing on the pinion and setup the correct preload.
 
There is a lot on that thread geared toward sales. In the old days we called it BS but that isn't correct anymore. Buyer beware is all I can offer.
The cut gears are track proven for 50 years.
 
The date code is 9/1973 so they should be 5 cut but the teeth appear equal- it just be my viewpoint. Drive is deep. Coast on the toe. If you can't get better adjustment and those are 5 cut I wouldn't use them.
 
GTR1999 said:
There is a lot on that thread geared toward sales. In the old days we called it BS but that isn't correct anymore. Buyer beware is all I can offer.
The cut gears are track proven for 50 years.
Click to expand...

Yeah, I read powedered gears were less desirable when I looked, but who knows times/technology changes.
 
Well the spider type was one thing, a steel cap on the RH side is just BS to sell someone something they don't need. I never believed in doing that or telling someone one thing and then not doing it.

To each his own but some of those threads on custom diff's have really pushed the limit of integrity for the profession. The sad part is there isn't anyone there that seems to realize what they see isn't what was offered. I hear about it because they get drawn in with someone offering lower prices and once they commit find a whole different deal goes down and some call to ask me to take on the build. I suppose it's nothing new in the automotive game it's just online now.
 
Thanks rtj for the info. And thanks Gary as well.
I will give it a try again to move the pattern. Pity that I cannot be sure of the number of cut. Another set back then..
 
Here is a set of Tom's gears I set up. These are 5 cut. Look at the teeth on your gear set, if you can see the Toe end is shorter then the heel end they are 5 cut. If the heights are the same they are 2 cut but I don't recall any 2 cut on original vette gear sets.

This is part of the build that many fail at because it is very time consuming- setting up a shim, lash, pattern, break down, clean, change and do it all again. Takes my about 40 minutes to do that change over.

oil1.jpg
 
Thanks Gary much appreciated. I have an even older GM's R&P so I will check the dimensions. And yes, time consuming but . I decided to work on it only in the morning and do something else the rest of the time , that way I can think calmly about and find solutions. :banghead:
Thank you again .
 
Alright ! talking about solution !
Out with the old and in with a new one.
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I cannot find if the R&P is a 2 or 5 cut and comparing to a 5 cut it looks the same for me and measure the same as well. So as I can't say that I trust the work of the previous guy, better to start new. Just more money !!
With a 3.73 from Tom's, my patterns should now match Gary's !
 
To continue on my build, I asked Gary to assemble and tune a new Posi for me and I think that is good to share the pictures that he's sending me. I'd love that all the guys I am dealing with for my car can do the same thing, keeping in touch !

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