Used ring and pinion contact pattern

5063 Views 10 Replies 7 Participants Last post by billdacat, Dec 13, 2010

JCRocks

Discussion Starter · Dec 1, 2010

I had a bad pinion bearing in the rear axle and decided to do the work myself. I only replaced both pinion bearings, the carrier bearings looked fine. I destroyed the pinion depth shims because they were under the cup and when I knocked the cup out the shims got messed up. I ordered a complete rebuild kit from David at Northridge4x4.com. I put the same thickness, but new, pinion preload and pinion depth shims back in place. The specs are:

Pinion Preload: 30 inch pounds
Backlash: .007
Carrier Preload: unknown. Reused the two existing thick shims and needed a hammer to knock one in place.
Ratio: 4.88 Superior

The gears have ~30,000 miles on them and look fine. My question concerns the contact pattern for used gears. I've read that with used gears you need to favor the patten on the coast side due to the wear on the drive side. Also, the pattern is fine if it's closer to the toe. Please look at these two pictures and let me know your opinion. Thanks -

Drive Side

Coast Side

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Eric

· #2 · Dec 1, 2010

I would call it close enough, looks about like my fronts which were used when i put mine in. although you have more pre load on the pinion than i did, and mine is a little noisy on the coast side when i let off the gas. the extra preload ought to take care of that.
JMHO tho

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Thom

· #3 · Dec 1, 2010

Perfect

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JCRocks

Discussion Starter · #4 · Dec 1, 2010

Thanks for the replies - It's always nice to have others look at the work. I'll remove the setup bearings and get it all back together.

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billdacat

· #5 · Dec 6, 2010

What a coincidence…I also replace a front outer pinion bearing this weekend. I had a bad drive-shaft u-joint as the cause of vibration that destroyed the outer pinion bearing. I had on hand both pinion bearings and pre-load shims. As a precaution before pulling the carrier and pinion, I checked backlash and found it to be right at .008” . I figured that if backlash is in spec; it wouldn’t be necessary to run a pattern. (Is this wrong?)
I thought that I was prepared to replace both inner and outer bearings, but upon removal of the pinion I discovered a slinger underneath the inner bearing cone. Using a conventional splitter and press; I would have most likely destroyed the slinger to remove the cone. In a way this was probably a blessing that I didn’t mess with inner bearing. A close visual inspection of the inner bearing and race didn’t disclose any discrepancies anyway.
The outer bearing had obvious damage caused by DS vibration. I tried to take a picture of the bearing race but not enough detail showed up to be of any value. (cheep camera) In preparation for this job, I had done some researched and found a Doctor D post about excessive preload. Thankfully this was not my case, and I didn’t have to adjust preload (22 in/lbs).

Looking back on this job, I have learned a few things. The clam-shell bearing puller has moved up on my Christmas list; and the existence of a special tool to remove the inner pinion race without damaging the shim-stack. (D-148)

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JCRocks

Discussion Starter · #6 · Dec 9, 2010

billdacat said:
I figured that if backlash is in spec; it wouldn’t be necessary to run a pattern. (Is this wrong?)

Not sure if it's required - I ran one because I replaced the pinion depth shim pack.

billdacat said:
Looking back on this job, I have learned a few things. The clam-shell bearing puller has moved up on my Christmas list; and the existence of a special tool to remove the inner pinion race without damaging the shim-stack. (D-148)

Those would be nice.

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gregert12

· #7 · Dec 9, 2010

The drive and coast look fine. I was taught by Dr D to look at the contact pattern from the paint that carries over to the next set of ring gear teeth.

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Stinger

· #8 · Dec 9, 2010

gregert12 said:
The drive and coast look fine. I was taught by Dr D to look at the contact pattern from the paint that carries over to the next set of ring gear teeth.

PICTURES!

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ekim

· #9 · Dec 9, 2010

billdacat said:
I discovered a slinger underneath the inner bearing cone. Using a conventional splitter and press; I would have most likely destroyed the slinger to remove the cone.

If the D44 is similar to the D30 the slinger under the inner bearing cone is called a baffle. My understanding is that a slinger spins while a baffle does not.

billdacat said:
I
Looking back on this job, I have learned a few things. The clam-shell bearing puller has moved up on my Christmas list; and the existence of a special tool to remove the inner pinion race without damaging the shim-stack. (D-148)

I don't see how the D-148 tool would get the cone out without messing up the baffle. You would need to be able to put it in from the front and slip it between the baffle and cup at an angle.

I understand the value of the clam shell puller for pulling carrier bearings when the shims are between the bearing and the carrier but are they useful for the pinion bearings since you would typically just press the bearing on and never need to take it off again?

It's worthwhile to carefully inspect the gears while things are out. I had a loose pinion bearing and did a quick look and all seemed fine. Then when buttoning things up I noticed some cracks on the ring gear...

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gregert12

· #10 · Dec 9, 2010

Stinger said:
gregert12 said:

The drive and coast look fine. I was taught by Dr D to look at the contact pattern from the paint that carries over to the next set of ring gear teeth.

Click to expand...

PICTURES!

No problem.

http://www.rubiconownersforum.com/phpbb3/viewtopic.php?p=623049#p623049

Sorry for the hijack.

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billdacat

· #11 · Dec 13, 2010

ekim said:
billdacat said:

I discovered a slinger underneath the inner bearing cone. Using a conventional splitter and press; I would have most likely destroyed the slinger to remove the cone.

Click to expand...

If the D44 is similar to the D30 the slinger under the inner bearing cone is called a baffle. My understanding is that a slinger spins while a baffle does not.

billdacat said:

I
Looking back on this job, I have learned a few things. The clam-shell bearing puller has moved up on my Christmas list; and the existence of a special tool to remove the inner pinion race without damaging the shim-stack. (D-148)

Click to expand...

I don't see how the D-148 tool would get the cone out without messing up the baffle. You would need to be able to put it in from the front and slip it between the baffle and cup at an angle.
The D-148 tool is used to remove the inner pinion bearing cup without dinging up the shims. I found one flea bay for a few bucks...

I understand the value of the clam shell puller for pulling carrier bearings when the shims are between the bearing and the carrier but are they useful for the pinion bearings since you would typically just press the bearing on and never need to take it off again? On some pinions, you may find a baffle or slinger between the inner cone and gear. A clam shell is the only way to get this bearing off the pinion gear without bending the slinger or baffle.

It's worthwhile to carefully inspect the gears while things are out. I had a loose pinion bearing and did a quick look and all seemed fine. Then when buttoning things up I noticed some cracks on the ring gear...

You got that right!!!

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