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14bff gear pattern

bp71k5

bp71k5

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I supposedly know what I'm doing now. This looks like the pinion needs to deeper (fewer shims) correct?

Backlash was at .006 in this picture and pinion shims are at .022"
Edit: Fixed the picture size.
IMG_0037.JPG

IMG_0037.JPG
 
Last edited:
Not sure what happened there. Bigger size now.

I did swap in a smaller shim and it does look better, the pattern may still be a little high, but I'm now down to a single .009" shim under the pinion and none of the rest of my shims are any smaller. The old gears were using about .022" of shims.
 
I think something got mixed up in those pictures. That one was after the pinion shim change.

Here's where I'm at now:
Pinion Shim = .007
Backlash = .008
backlash007.JPG


That looked a little too much heel so I decreased the backlash to .004 here.
backlash004.JPG

I'm using the thinnest pinion shim I have which is .007" so I can't got much deeper without finding more shims, but this doesn't seem that far off does it?

backlash007.JPG

backlash004.JPG
 
Not deep enough, try using no pinion shims. Unfortunately, I bet you'll need .003" or so.

Don't worry about heel to toe, there's not much you can change there (by adjusting backlash) and it doesn't matter much anyway.

Keep your backlash in spec, don't worry about the heel to toe contact on the gears.
 
Post up a picture of the coast side contact pattern as well. That will help determine if there are any other problems.

Try and keep the back lash closer to .008".
 
The backlash spec is .005"-.008" and you need to check it in 3 places.
 
I'm a little worried that I don't appear to have overshot the pinion depth by removing all the shims. Now backlash = .007"

Drive side
.007-noshimdrive.JPG

Coast side.
.007-noshim coast.JPG

.007-noshimdrive.JPG

.007-noshim coast.JPG
 
That pattern actually looks pretty damn good, I've setup a few diffs that didn't use any pinion shims.

If you're confident that everything is clean (or was clean when you put it together) I'd run it.
 
Everything is clean, but I do still need to fully torque the bearing caps. The left side may not be fully tightened because the bracket for the arb prevents me from getting a socket on it. The only socket i have in that size has a very thick wall so I used a box end to tighten it as much as possible.

If the pattern is decently close, I'll pick up the right socket and re check everything to make sure it's really ok.

Thanks for the help.
 
That will work but will be somewhat noisy.

If you want it perfect you'll need to remove the pinion bearing and install a .020" or so shim to get that pinion depth perfect.

The target is to get the pattern on both sides of the tooth to be in the same relative position heel to toe. With the coast side being so far in and the drive side a little far out I'd guess you'd need about another .008" to get it right on the money. Just make sure you have enough clearance between the head of the pinion and boss for the pinion pilot bearing.
 
bigblock72 said:
That will work but will be somewhat noisy.
Click to expand...

I disagree

bigblock72 said:
If you want it perfect you'll need to remove the pinion bearing and install a .020" or so shim to get that pinion depth perfect.
Click to expand...

Moving the pinion another .020" deeper will make the pattern WAY too deep.

bigblock72 said:
The target is to get the pattern on both sides of the tooth to be in the same relative position heel to toe. With the coast side being so far in and the drive side a little far out I'd guess you'd need about another .008" to get it right on the money. Just make sure you have enough clearance between the head of the pinion and boss for the pinion pilot bearing.
Click to expand...

IME (and from everything I've read) there isn't much you can do about heel to toe contact and it isn't very important.

Here's Yukon's installation instructions they would tend to agree with me (page 14)

http://www.ringpinion.com/Content/H...tions/Yukon_Installation_Kit_Instructions.pdf
 
I've set up thousands of gear sets (I worked at Jeep during the aluminum 44 days) it will be somewhat noisy, I don't know if it will be audible in an old Blazer but it sure would be noticeable in a newer truck or Jeep. I don't think it will cause problems either I just want to post the correct way to set up a gear set because of all the misinformation on the web.

Yes .020" would be way too deep but it would give you the ability to add another shim behind the pinion support to get it right on. As I posted in the next paragraph it probably needs about .008".

Pinion depth has everything to do with the heel to toe contact REGARDLESS of what anyone posts on their website. You don't have to believe me but at least try adding a shim and see what happens to the pattern. I promise the coast side will move one way and the drive side will move the other.


I don't want to turn this into a pissing match so take it for what it's worth.:crazy:


Chad
 
So you're saying put a shim under the pinion bearing then press it back and then put a shim under pinion carrier to correct the low coast side.
 
cuervo said:
So you're saying put a shim under the pinion bearing then press it back and then put a shim under pinion carrier to correct the low coast side.
Click to expand...

Yea, thats what he means and it makes sense. I'm going to first try checking the torque on all the bolts and double check the mating surfaces to see if I can squeeze another .001" out of it and see where that leaves me. I'm leaning towards just running it since a new crush sleeve would be such a pain at this low altitude. :)
 
The torque on the carrier caps WILL AFFECT backlash and gear mesh. You cannot expect to get a correct reading if something in the mix isn't set properly to begin with.

It's like trying to check the housing bore (big end of a rod) with the cap only snug, the diameter will be different than with the cap torqued to spec.
 
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