D30 Pinion preload ?

[montanaman]

'91 XJ

I'm changing the pinion seal on my '91 High-Pinion D30.

The tag has the following numbers:

52068047
3.07 610318-5

The '91 Factory Service Manual says to first measure pinion bearing preload with an inch-pound torque wrench *before* removing the pinion nut. Then, when replacing the pinion nut, retorque it to 5 inches over the first measurement.

The problem is, I took the shaft off, and put a little beam-style in-lb torque wrench on the pinion nut, and it's not measuring any preload at all ... maybe 1 or 2 in-lbs. The axles are removed, but the carrier and ring are still in. Also, when I grab the yoke and wiggle it, it seems to have a touch of end-play. Not much, but enough to feel it and hear it a little. The turning feels smooth through the complete turn.

I haven't removed the pinion nut yet, because I want to make sure I know what I'm doing first.

So ... some questions:

1.) - Does anyone know if this is a crush sleeve or shims? The '91 FSM says shims, but it's been wrong before (it only covers pre-Denso alternators, which were discontinued after 1990).

2.) - If it is shims, does anybody have a part number for the preload shims? I can't find them on rock auto, napa, oreilly's, autozone. I can only find a complete shim kit, which costs about $50. That's a lot to spend when I only need a few little shims to set the pinion preload.

3.) - If it is shims, do I just remove the outer bearing, then add shims or is there something else that needs to be removed before adding the shims? I want to make sure I get the order right.

4.) - FSM says to set preload to 10-20 inch-pounds when reusing old bearings. Is that preload measurement with carrier installed or out?

5.) - Is it possible to convert a shimmed D30 to a crush sleeve for pinion bearing preload? Crush sleeves cost 4 effing dollars, not 50, and they are easy to get, and I know exactly what to do with them.

Thanks in advance for any help/advice you can provide. I'm kind of pissed off. This is supposed to be a "Simple" job, and I want to get it done.

 

[Anak]

I expect it is shims. That is what is in my '92 HP D30.

I am no expert on the topic, but I do not think you should need to change the shim pack. I think that would only create a need to reset everything. I would not want to go there.

I think what you are looking at is a need to tighten the nut just a bit more tight than what it was before.

The person you really want an answer from is Matt (XCM), but he doesn't poke in all that often lately.

 

[montanaman]

Yeah ... I think it probably is shims. But ... there are two sets of pinion shims ... one for setting the pinion depth to the ring gear, and another set for setting the pinion bearings preload. I'm hoping that if I need to mess with the preload shims, it won't require resetting pinion gear depth. I have too much other crap to worry about. I want to take my family to Moab for some jeeping/camping/mountain-biking, and I need to get this baby back together.

I think I'm going to go back out and check the nut torque to see if I can tighten it a bit for more preload.

 

[md21722]

The LP axles are crush sleeve The HP axles are shims. To adjust the shim stack you need to get the seal and outer bearing off. Typically the carrier is removed, and the pinion driven forward. Each .001" of a difference is equal to about 8 in-lb. The Spicer parts list says to look up shim kit packages for these. The smallest kit is 706936X. It includes 701010X which are the pinion preload shims. If you can find 701010X by itself, then great. Since you should use a new washer, seal, and pinion nut, buying one of the kits is a decent idea.

 

[montanaman]

Thanks for your answer.

So I guess converting to crush sleeve is not possible?

Will changing the preload shims affect the pinion depth settings?

It sounds like you're saying to measure preload with carrier out ... is that right or did I misunderstand?

Sorry for the noob questions ... I'm still learning about this setup.

Thanks again.

 

[md21722]

I am not aware of any shim to crush sleeve conversions.

Pinion depth is set from the factory with pinion depth shim under the pinion head and the baffle under the inner pinion bearing. The factory has a series of variable thickness shims for under the pinion head so they primarily relied upon that and the baffle being .020". In the aftermarket world, the standard shim under the pinion head is around .030" and you put shims and baffle under inner pinion bearing race.

However, since these bearings are worn, tightening them up could cause some depth changes as the bearings themselves play a factor in the depth. If they are so worn to be at zero preload with noticeable play the bearings should be replaced for a complete repair.

The carrier is removed when figuring out the pinion preload, and it only makes sense to do so, since you are typically driving the pinion out of the outer bearing by using an air hammer with a pointy bit, a centering punch with a heavy hammer, or a heavy soft faced dead blow depending on how hard it is to drive out, and your style.

Once you get the pinion out you can inspect the bearings and see what's going on with them.

Be aware that if you have to drive the pinion out with high force, the bearing on the pinion head may shift so the shim will turn. If that occurs, you will need to press it back into place. A bearing splitter is cheaper, but the preferred tool to pull carrier & pinion head bearings is the clamshell puller. They range from about $250 - $500 depending on what brand/colors you buy but as far as I know they are all made in the same factory in India.

If good used axles are available, its often cheaper to replace the entire axle, but in your area they may not be available.

 

[dan1977p]

How important is it to stop a drop or two of oil? If I was doing it, I'd mark the nut, remove it, replace the seal, red locktite and retorque the nut back to its original location. Wasn't it leaking because of a clogged vent, though? Is it still leaking now?

 

[montanaman]

Hi Dan:

I'd love to just put it back together like that. The problem is that it is already showing no preload on the pinion bearings. That's really bad. While I was going in to replace a seal, I discovered a major problem with my diff. The leaking seal is the least of my problems now. I can put it back together, but I don't know how long it will last.

At this point, it seems the best thing to do is get a rebuild kit and do the whole freakin' thing ... new carrier bearings, pinion bearings, and reset backlash and pinion depth properly. I either need to learn to do this myself, or I need to do all my other front end work, put it back together and take it to an axle shop for the rebuild.

 

[montanaman]

does adding preload shims increase preload, or reduce it? There are conflicting accounts of this. The FSM says adding shims increases preload, but that doesn't make sense. The shims are between the bearings, and the bearing cups are inside the bearings, so it would be logical more shims would move them farther from their cups. Every other source I have found says more shims decreases preload ... but the FSM says the opposite.

Does anyone know?

Thanks.

 

[md21722]

Adding to the pinion preload stack decreases pinion bearing preload.

Adding to the carrier bearing shims stacks increases carrier bearing preload.

 

[montanaman]

Right. What you are saying is the right thing.

The FSM calls the spider gears "Side Gears" (2) and "Drive pinion gears" (2). I was confusing the "drive pinion" spider with the pinion head gear. Nomenclature issue.

I just got off the phone with a 4x4 shop owner who has done this a lot. He recommended just resetting the pinion bearing preload and putting it back together. He said it's really not worth the cost to do a complete rebuild. New gears and a complete rebuild kit would cost about $700-$800 including labor.

He said the pinion depth probably will go back to where it belongs with the pinon bearing preload re-adjusted.

I'm going to do that, run a pattern, and see what I get.

 

[md21722]

Unless the gear set is worn there is no need to change gears.

The preload spec for used bearings is quite low.

A .001" difference in the shim stack can be the difference between in spec and out of spec.

 

[montanaman]

Unless the gear set is worn there is no need to change gears.

The preload spec for used bearings is quite low.

A .001" difference in the shim stack can be the difference between in spec and out of spec.

well ... the diff has 260K miles on it. The shop guy I talked to said that when they wear in a certain pattern, it can be very difficult to get them set up with new bearings, because the new bearings cause a new backlash and pinion depth, which results in an odd wear pattern. Unless you throw gobs of $$$ time at it. He said new gears can be much faster to set up, which saves money.

This is really a drag ... I just realized ... I was spinning the pinion AND the carrier and getting zero preload ... that's a serious problem, isn't it? I don't think it would be ok to just reset the pinion preload and call it good.

Thanks again for all your patient explanations. You sound like you know what you are talking about. Have you done a lot of axles?

 

[md21722]

I have not done a lot of axles but I have done my own for the past couple of years.

Setting up gears is more art than science.

I wouldn't be too concerned about the low/zero preload. I am pretty sure my 01 XJ with 350,000 has no measurable preload on the bearings, no slop, no leaks, and no noise. No telling how long its been that way. If you have noticeable slop like you can push pull, etc then I would be concerned.

I have had no problems setting up used factory gears. If they look burnt or worn get another set.

 

[montanaman]

If you have noticeable slop like you can push pull, etc then I would be concerned.

Thanks again for all of your help. I can feel the tiniest bit of play when I wiggle the yoke. It feels like end play, but it's hard to tell with such a small amount. There are no unusual sounds. Perhaps I should remove the pinion shaft, take out .001 or so, and call it good?

Or maybe put it back together with just a new seal?

I've been reading up on the process of rebuilding diffs and setting up gears, trying to decide if I'm up for it or not. It's really tempting to just put it back together with a new pinion seal and new inner axle seals and get on down the road.

What do you recommend?

 

[md21722]

If the pinion has any detectable slop I would pull it and deal with it. If you are changing the inner axle seals you will have to remove the carrier anyway, so enough apart to check the condition of the bearings & make a better call. That's just me. Axles can be funny sometimes. I have seen carriers that are hard to remove with bearings shot and others that just pull right out yet everything looks fine & the pattern was still good. I would be more sensitive to worn bearings w/ zero to minimal preload if I was bouncing around on fire roads. What works on the highway may not take a beating off road.

 

[montanaman]

Ok ... It's been raining, but I got out today, and took things apart. The Carrier bearing race is badly pitted on the ring side, so I'm going to do the full rebuild, but will keep the old gears, since they don't show any obvious signs of wear or damage.

Any brand recommendations for a rebuild kit? Spicer only? A gear shop I talked to said they use "Rhino" brand and they think it is as good or better than Yukon.

I'm thinking I'll just replace all four bearings and make sure the gears are set up properly. Maybe also replace the side spider gear thrust washers.

Anything else I should do while I'm doing this?

Thanks to everyone. I've learned a lot from this process.

 

[md21722]

I prefer the shim sets in the Spicer kits over the ones from Yukon. I have never used Rhino. Keep your eyes open for surprises. You may think you can just throw in new bearings and call it good until you realize one of the old bearings was .100 under and all of a sudden the carrier will not go back in. Not saying it will happen, but it could.

 

[cp2295]

D30 HP is a shim style pinion, there should be no play in the pinion, it needs pre load its more of a feel thing. I usually shim the bearings until it has a slight drag. Hard to explain but ill try, if you try to spin the pinion quick and it spins no problem its too loose. If you spin the pinion and it feels notchy and tight, its too tight. If u spin the pinion (hard) and it spins about 3/4-1 full turn and feels smooth no notchiness in it, then its correct. Set all my pinions like that and have never had a problem.


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