pinion depth shim ?

[65-440]

Ok, assembled my new truetrac and all new bearings yesterday and had to set up the gears all over again. First pattern was way to the inside of the ring gear. That was with a .034" shim. After a bunch of shims and patterns later, ended up with no pinion depth shim in order to get a good contact pattern on the drive side. Coast side moved but but the best. Has anyone ever came across no pinion depth shim needed ?

 

[oldbee]

I've only done 2 myself, but it's all in machining of everything. R&P and the housing; sure, it could work out that way.

 

[moper]

I've done a bunch, with various different parts. I've never had one that took nothing. The pinion depth shim is for machining differences in the bearings, pinion gear, and case. If there was a shim, and the parts are correct and in correctly, the same shim should work. I can't tell by your pictures if the pattern is good. I don't see much "pattern" visible.

 

[Cranky]

Never had one to take no shims either and I also cannot tell much on what the pic shows. Try wiping off the ring gear totally clean and just painting the pinion only and then roll it through and see if that doesn't help show the pattern better....

 

[dvw]

That is not the pattern you are looking for. Go to Motive Gear patterns and read. Though this pattern is a touch deep it's close. Drive is more important than coast.
Doug

 

[john-9]

first off i take it by your shim selection ( .034 ) you are working on a 489 case --- i usually start any 489 build with a .030 shim and make moves up or down in thickness depending on the pattern the gears roll ---
what have you set the backlash at and you do have preload on the pinion bearings ---- have you applied any load to the ring gear while turning the pinion to check your pattern.
your pics shown no contact at all --- and to have a case and gear stack up for no pinion shim would be extremely rare.
here are some pics of units i have set up ,,you should have similar results

 

[Cranky]

first off i take it by your shim selection ( .034 ) you are working on a 489 case --- i usually start any 489 build with a .030 shim and make moves up or down in thickness depending on the pattern the gears roll ---
what have you set the backlash at and you do have preload on the pinion bearings ---- have you applied any load to the ring gear while turning the pinion to check your pattern.
your pics shown no contact at all --- and to have a case and gear stack up for no pinion shim would be extremely rare.
here are some pics of units i have set up ,,you should have similar results View attachment 522006 View attachment 522007

How do you load your ring gear for checking the pattern and do you use a pinion depth checking tool for initial setup? I have an old Pro Parts pinion depth checking tool and the first time I set up a set of gears, the pattern just didn't look right to me. The next move was to plug them into my car and go for a test drive. They were quiet and stayed that way well after break in. Did the same thing for the next few setups until it built up trust for the tool and started doing gear work for others. Also noticed a little bit of difference in patterns between the two units....

 

[john-9]

How do you load your ring gear for checking the pattern and do you use a pinion depth checking tool for initial setup? I have an old Pro Parts pinion depth checking tool and the first time I set up a set of gears, the pattern just didn't look right to me. The next move was to plug them into my car and go for a test drive. They were quiet and stayed that way well after break in. Did the same thing for the next few setups until it built up trust for the tool and started doing gear work for others. Also noticed a little bit of difference in patterns between the two units....

been building diffs since 1975 and have always been old school -- pattern determines pinion depth shim --- always starting with a nominal shim .020 for 8 and 9 inch Fords ,, .030 for Chrysler 489 cases , .090 for 742 and so on depending on what differential ( Ford , Chrysler, Gm etc. ) i am working on and move up or down in shim thickness to determine proper pattern.
no 2 gears sets are alike and the proper gear pattern will differ in shape between them
i load the ring gear with the palm of my hand and rotate the pinion to roll a pattern as seen in the photos.

 

[Cranky]

been building diffs since 1975 and have always been old school -- pattern determines pinion depth shim --- always starting with a nominal shim .020 for 8 and 9 inch Fords ,, .030 for Chrysler 489 cases , .090 for 742 and so on depending on what differential ( Ford , Chrysler, Gm etc. ) i am working on and move up or down in shim thickness to determine proper pattern.
no 2 gears sets are alike and the proper gear pattern will differ in shape between them
i load the ring gear with the palm of my hand and rotate the pinion to roll a pattern as seen in the photos.

You got a few years on me. Didn't start doing gear work until around 1980 or so but pretty much stuck with doing 8 3/4's and 60's with a 9" being thrown in here and there.