Real time: my gear pattern

[Mixelplix]

Correct, I did not mix pinions. I'm using a new matched set

The point I was trying to make before is that I switched methods of shimming the pinion due to me having to reduce the shim stack thickness

Yesterday I had the shim on the pinion (between the bearing and the head), and today I've removed that shim and began shimming the bearing race.

The pinion shim (yesterday's method) is solid and .0795 thick. Since everyone recommended to reduce the shim size I switched to the shim stack under the bearing race method.

Does that make sense?

 

[landtank]

yes it does. I hate the race shim method. The bearings supplied are usually harder to drive out as they are not the same as the factory bearing. Same supplier and overall height but not the same bearing.

 

[gearinstalls.com]

I don't believe that he is mixing pinions. These are a new set of 4.88s.

It is very strange that the pattern looks like the pinion is deeper after using a .0095 thinner shim. Something is not right. Either the bearing isn't seated, or there is a piece of dirt in the shim stack or the measured thickness is off.

You're right....I misread it a little bit. I agree that it's very strange that the pattern appears deeper with less shim.

 

[gearinstalls.com]

Correct, I did not mix pinions. I'm using a new matched set

The point I was trying to make before is that I switched methods of shimming the pinion due to me having to reduce the shim stack thickness

Yesterday I had the shim on the pinion (between the bearing and the head), and today I've removed that shim and began shimming the bearing race.

The pinion shim (yesterday's method) is solid and .0795 thick. Since everyone recommended to reduce the shim size I switched to the shim stack under the bearing race method.

Does that make sense?

yes, acceptable to do it either way.....

 

[Mixelplix]

I think things are improving.

I double checked everything I did previously, and in that process I found that my inner bearing was not fully seated on the pinion head.

I also did as suggested, and rapped everything with a brass drift in an attempt to settle the bearings.


Same settings as before:

.070 shim pack (under bearing race) 006 backlash

 

[Pin_Head]

It looks much better, but you want to hold the pinion flange with a shop rag to put some resistance and pressure on the teeth while you rotate the ring gear with a wrench on one of the ring gear bolts. That should make a much clearer and less messy looking contact pattern.

You could probably stop there. It still looks slightly deep, which is good. Make sure the backlash in within spec. .006 sounds kind of tight.

 

[Mixelplix]

FSM asks for a backlash range of .0051 to .0071

I updated per your suggestion. You're right, much more clear:

 

[Krazytoy]

You can also thin the marking compound with some engine oil for a more clear pattern.

 

[Pin_Head]

I would run it. It looks good.

 

[gearinstalls.com]

Good job! Leave it alone.

 

[Railwelder93]

Maybe this can be a collective pattern check thread

Anyway, have a look. Any thoughts?
BL dead on .007

new gears btw. Replaced R&P with locker install due to chewed up threads on the last pinion.
Re used the factory pinion shim.

 

[flintknapper]

Maybe this can be a collective pattern check thread

Anyway, have a look. Any thoughts?
BL dead on .007
View attachment 2349235
View attachment 2349236
new gears btw. Replaced R&P with locker install due to chewed up threads on the last pinion.
Re used the factory pinion shim.

Good job, I'd run that.

 

[Railwelder93]

Good job, I'd run that.

That’s what I’m thinking, but I’m holding up to think about it for a min.

so the coast side looks great I think, but I’m not sure that really matters. Looking at the diagrams I have the shape of the drive side pattern looks like the pinion is too deep, however regardless of the shape the mark is centered between face and flank.

That’s really all that has me thinking about messing with it more, even though I think what I have looks ok.

 

[flintknapper]

That’s what I’m thinking, but I’m holding up to think about it for a min.

so the coast side looks great I think, but I’m not sure that really matters. Looking at the diagrams I have the shape of the drive side pattern looks like the pinion is too deep, however regardless of the shape the mark is centered between face and flank.
View attachment 2349338
That’s really all that has me thinking about messing with it more, even though I think what I have looks ok.

I've set quite a few diffs on my vehicles over the years (50 yrs) and what you have now is fine. Keep messing with it....and it won't be. Unless you're racing or rockcrawling....I'd leave it alone

 

[Railwelder93]

I've set quite a few diffs on my vehicles over the years (50 yrs) and what you have now is fine. Keep messing with it....and it won't be. Unless you're racing or rockcrawling....I'd leave it alone

What is your opinion on the carrier preload?

I set mine hand snug with no backlash then tightened pinion side until ring side deflected dial indicator. Then tightened 1.5-2 holes past that point. I understand that is what Fsm calls for, but a bit of reading I’ve done on here leads me to believe slightly more than this is better.

 

[Mixelplix]

Wow, fun to see this thread bumped!

I've been running my 4.88's since 2013 (now 2020) with the pattern shown above with no issue.