Round 2 with rear end rebuild

[moper]

I wouldn't have let you take that. The pattern sucks, pinion setting gage or not. IMO .010 backlash is a little too much, given the patterns (coast and drive sides) look ugly to me too. If the patterns were great the backlash wouldn;t be much of a concern but there's something that's not quite "there" yet. I would try moving the pinion deeper, and use a little less marking compound when you check it.

 

[multipleBs]

The pattern does look a little deep, I've never set one that deep, but you need to remember that under load the pattern will tend to move up and out along the tooth so it could be OK. You need to move both adjusters to get both the right backlash and preload. Looking from the rear the left adjuster would have to be a little tighter and the right adjuster slightly looser, assuming the preload is currently correct. The correct way is back of the right adjuster, tighten the left and then tighten the right for preload, then recheck the backlash and pattern. Don't be surprised if a couple of tries are needed to get both where you want. As for the depth of the pattern it doesn't look ideal. See attached for what to aim for.



A thinner pinion spacer should get you where you want to go.

 

[AR67GTX]

Well - this is not very promising. However, I don't see much choice except to chunk it in first, button it up and see what happens. The rebuilders has already set this thing up 3 times (twice on his nickel) so my bringing it back to him again w/o first installing it and seeing what happens is a non-starter. At least I'm getting pretty fast at removing and reinstalling the thing.

 

[moper]

Agreed. It's his dime at this point. I'll add too - I worked for a while at a 4wd shop in addition to my car sidework since the 80s. There are some rear sets that literally fall into place. And others that you would think will be slam-dunk and take an act of God to finally get right. I think the worst I've had took me 5 set-ups. 2 after it looked good but not perfect and I said "good enough" and replaced the checking bearings with the permanent stuff. As long as he's still trying to make it right he's doing his part.

 

[747mopar]

I have read that noise is a common treat with Richmond Gear.

I ran a set of 4:30 Richmond gears with no noise at all?????

That's embarrassing if you ask me to be a shop and call that done!!! Like everyone is saying it looks deep. My very first shot at one looked way better than that thanks to people like Cranky giving me pointers. It's a matter of not saying "good enough" IMO.

 

[bm02tj]

On my Jeep site one of the techs used a scotchbrite on his dremel to polish the edge burrs from the machining on the teeth and saying this will insure they are quiet

 

[AR67GTX]

I was reading on the Richmond website that the gear set target backlash should be marked on the ring gear - such as .008. I've looked mine over closely and can find the CD measurement for the pinion depth but nothing indicating target backlash. Has anyone found a backlash measurement marked on their gear set? Interestingly, their gear patter wear examples do indicate typical contact would be offset from the center a bit towards the ring gear center (toe). Mine is a bit off in that direction as near as I can tell - contact area seems awful narrow however.

Anyway he said he really liked that Lucas differential lube I had in it the last time - seemed extremely slippery as he disassembled it. So, plan to go back with it in 140 wt this time and keep my fingers crossed. I noticed a lot of these rear gear lubes say there isn't a need to add a limited slip additive to them - is this BS or are some of them fine without the additive?

 

[dvw]

That pinion looks Way deep on the new ring gear. Backlash or no backlash the pattern is incorrect.
Doug

 

[coloradodave]

When you get the pattern squared away, USE the MOPAR additive. I tried other brands and always ended up changing back to the factory stuff to get smooth operation. Do you have to use it? IMO, categorically, yes!

 

[multipleBs]

It's normal for the pattern to look quite narrow as there is little load on the gears when bench testing. The forces are enormous on a fully loaded gear set. I've always used the additive, in fact I find the effectiveness of the additive seems to dissipate over time resulting in some shudder when cornering under light acceleration. Fresh additive always eliminated the shudder. It actually increases clutch slippage under light loads much the same way ATF+4 acts compared to DEXRON III. I haven't seen any backlash markings on gears, just offset markings on some to give you an idea which pinion spacer to use as a starting point. It's common to see thing like +2 or -3. The actual markings are usually on the head of the pinion, and aren't stamped like part numbers but hand marked by the inspector.

 

[AR67GTX]

Thanks - I'll pick up a bottle of additive just to be safe. May hold off adding until I take a short test drive to see how it sounds first.

 

[AR67GTX]

No success. Quiet under light power and cruise but sets up a loud (and I mean real loud) howl as soon as I let up on the gas. Howls all the way down to 20 mph even if I pop it into neutral. Tried running backwards in a parking lot a little which did nothing. Only about 8 - 10 miles on it so hopefully I can figure out something to salvage the gear set.

 

[multipleBs]

I wouldn't condemn the gearset unless you had a perfect contact pattern, backlash at the lower end of the range and still had a lot of noise. While some gears are noisier than others, you said explicitly that it's REAL LOUD. Definitely not normal. I know you gave your guy a chance to redo his work but I don't think you're going to be satisfied until you get some pinion spacers, reset the pinion depth yourself, recheck the pattern and set the backlash to the minimum spec. A good contact pattern is essential for long life but personally I've found that the amount of backlash on a new set is what most affects gear noise. You're too loose for a new gear, and it will increase with wear. Always go for the minimum end of the range on a new set. The problem with most places doing it professionally is that they just say it's good enough and send it out. Most customers will just install it and run it without checking anything. You're already way beyond that point, just a few more steps to finish the job.

 

[AR67GTX]

It was startling loud - probably twice what I was dealing with before - sounded kind of metallic - not sure how to explain. As I coasted down to 20 mph it became intermediate a few times before going silent. Seemed completely silent pulling away and cruising along.

I would dive into the thing myself but this is a 489 case with a crush sleeve which I think additionally complicates going in and making minor adjustments to the pinion shimming without affecting pinion bearing preload. Someone who works on these would have to weigh in on the accuracy of that thinking.

What I can read in the shop manual does seem to indicate that coasting noise is typically addressed with adjusting pinion depth so I'm gathering that the slightly less complicated process of tightening up backlash would probably not do much. Does that sound correct? I read a variety of opinions on what causes coasting whine/howl including:

- pinion nut is loose/preload lost - sort of doubt it since it's just been assembled.
- backlash is too great - maybe but shop manual indicates it affects the drive side more than the coast side.
- pinion depth - coast side contact looked a little off to the inside - probably a good chance of this.

Guess it's already time to pull it out again.

 

[multipleBs]

Both pinion depth and backlash really have to be correct for it to be quiet. Crush sleeves don't really complicate things, a fresh one should be used each time though. You're getting a good workout taking that thing out and putting it in, think of what you're saving on gym memberships.

 

[dvw]

I set them up w/o the crush sleeve . Tighten the nut enough to get some pinion preload, install the carrier and set to zero B/L. Tighten the opposite adjuster until you have the proper back lash (.006-.008). Now take a pattern. If it's wrong the pinion needs to be moved, only, nothing else. Move the pinion and recheck. Once you have a good pattern by repeating the above process tear it back down and install the crush sleeve.
Doug

 

[multipleBs]

Doug is bang on, that is the correct procedure. By "using a fresh one" I meant a used one should never be re-used in the final install, not that you needed a new one for every trial fitting. I should have been clearer. The crush sleeve is only there to prevent excessive pinion movement under actual load not using it will not affect a trial fitting as long as there is at least some preload applied, it doesn't need to be excessive.

 

[snakeoil24]

Doug your are explaining this perfectly. Multiple B is telling you the exact issue with Crush Sleeves...