Non-xj question for gearheads

Co-worker friend has a 1996 Dodge fullsize Ram 1500 4x4

Just had a reputable local shop in san diego install Richmond 4.56 gears front and rear, as well as a brand new rear LSD, because the old one was busted when they took it apart.

Truck as a 318, auto, so whichever rearend would be stock for that.

He picked it up late last week, and drove it a bit over the weekend around town, using the normal break-in routine that was prescribed and then to work on monday.

He immediately noticed a very palpable chatter/shudder from the rear as he was nearing our workplace.

He's a very mechanical/handy guy (rebuilt his motor and trans, actually) and simply wanted to drop his truck off for axle work to have them setup properly, since he was running short on time for this project.

Problem is, when he took the truck back to the shop, they said it's a normal charactoristic of the LSD to shudder/chatter like that. Truck did nothing of the sort when he dropped it off, and they're saying that's likely because the LSD was in fairly inopperable condition.

Does this sound normal? Not sure on the brand of LSD. Eaton maybe? Did they come stock with something like a trac-Loc? I can find out if that's important. Apparently the fluid levels including friction compound/modifier were all correct when re-checked.

i was going to suggest the friction modifier, but i guess not...
i know it's a different beast, but my limited slip in my mustang never made a sound unless the fluid was shot, then it would pop ocasionally when changing direction. i rebuilt it and i wouldnt have even noticed it was there except for roasting both tires.

x2 on what vanimal said, a LSD should be virtually silent unless something is wrong.

Vanimal said:

i was going to suggest the friction modifier, but i guess not...
i know it's a different beast, but my limited slip in my mustang never made a sound unless the fluid was shot, then it would pop ocasionally when changing direction. i rebuilt it and i wouldnt have even noticed it was there except for roasting both tires.

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Yeah, see that was his first thought, and what he expected them to say.

He expected them to say, oops, we forgot to add it. If it blows up we'll warranty it, but we'll add it at this point anyways, to see if it fixes it".

just add a tube of posi additive, you will know if thats the issue or not with-in about 3 miles of driving. That rear diff can take alot of oil and if only one tube, or bottle was used, it might not have been enough.

Its fast and easy and only about 5-7$ to do. And then you will know.

GrimmJeeper said:

x2 on what vanimal said, a LSD should be virtually silent unless something is wrong.

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10-4.

I was checking his truck out @ lunch, before he knew the LSD was having issues, and I remember also that he said that they commented that "the gears are normally noisy in these trucks, so any gear whine he might hear is normal...".

Sounded somewhat fishy to me, but he wasn't having issues, so I didn't say anything.

Could a audible gear whine (front and possibly rear) and this chatter be chalked up to gears as well?

RWKHausSupply said:

just add a tube of posi additive, you will know if thats the issue or not with-in about 3 miles of driving. That rear diff can take alot of oil and if only one tube, or bottle was used, it might not have been enough.

Its fast and easy and only about 5-7$ to do. And then you will know.

Click to expand...

x2 on this. It wont hurt to try it. They probably forgot it and dont want to admit it, or they didn't use enough.

RWKHausSupply said:

just add a tube of posi additive, you will know if thats the issue or not with-in about 3 miles of driving. That rear diff can take alot of oil and if only one tube, or bottle was used, it might not have been enough.

Its fast and easy and only about 5-7$ to do. And then you will know.

Click to expand...

10-4, I'll tell him to try that. He's going to see the mechanic I trust over in Santee this week, so maybe they can simply pull the fill plug and add it while he's over there.

SanDiegoOverland said:

10-4.

I was checking his truck out @ lunch, before he knew the LSD was having issues, and I remember also that he said that they commented that "the gears are normally noisy in these trucks, so any gear whine he might hear is normal...".

Sounded somewhat fishy to me, but he wasn't having issues, so I didn't say anything.

Could a audible gear whine (front and possibly rear) and this chatter be chalked up to gears as well?

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"normally noisy"??? WTF, this guy is trying to cover his bases.

the chry diffs are the hardest to get quiet out there. But a Quality gear set typically can curb any noise when installed to correct specs.

But in a truck and even with a decent to average gear set in the back, you should not be able to hear it ever.

If it was a van or a wagon or even a XJ, with a street tire and super quiet exh, then MAYBE you might hear the gears, if not perfectly setup and with a quiet cut set. But even then, it would be faint.

JohnX said:

"normally noisy"??? WTF, this guy is trying to cover his bases.

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I know, right? My diff whines, but it's because the D35 pinion bearing is going south. I don't care cuz I have a 8.25 in the garage that's ready to swap in at any point that it's needed.

I don't know dodge drivetrains very well other than the motors, so I didn't make any comment at the time.

My 8.8 makes a little chattering when making sharp turns on the street. I don't use friction modifier with the lsd, so it grips better offroad. Hop adding a bottle will solve the issue.

What gears did they replace it with? Some brands can be noisier than others, and most are noisier than oem gearsets.

souske said:

My 8.8 makes a little chattering when making sharp turns on the street. I don't use friction modifier with the lsd, so it grips better offroad. Hop adding a bottle will solve the issue.

What gears did they replace it with? Some brands can be noisier than others, and most are noisier than oem gearsets.

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Richmond 4.56's...not sure on the LSD. Pretty sure it was a stock replacement, though.

SanDiegoOverland said:

Richmond 4.56's...not sure on the LSD. Pretty sure it was a stock replacement, though.

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Richmonds are typically one of the more possibly noisy, due to the cut being more for strength.

RWKHausSupply said:

Richmonds are typically one of the more possibly noisy, due to the cut being more for strength.

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Ok, well that tends to swing my attention back to the LSD.

BTW, I passed on the "adding friction modifier advice to my buddy, and his response was that he had already planned on stopping and picking up a bottle on his way home today, so that's a good start, I think.

Any chance that shudder could be a u-joint that is marginal. Perhaps it was disturbed when the driveshaft was reinstalled after the gear change.

David Bricker / SYR

If this is still an issue, send me a PM. I'm a little out of the way, but I know Chrysler/Jeep/Dodge diffs.


Justin

what shop?

rockclimber said:

what shop?

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MIT in el cajon.

Ok, so he added the friction modifyer, and took it for a few test drives around town, and it was still having issues, even more pronounced than when I talked to him last.

He ended up taking it back and taking the owner on a drive. Long story short, the owner was like "Oh man, that's not right." He ended up ordering him/pulling from stock a new ring and pinion on their dime and installing it.

Not sure what was wrong with the first set, but he said after doing the break-in dance once again, they're completely different. NO issues. He said that when they pulled them, re-"setting them up" wouldn't have helped as they were fully buggered by just driving it. (My friend pulled his diff cover the afternoon/night he noticed the chatter/noise and found no chunks/markings,shavings, etc so were kinda scratching our heads on this part...maybe it just hadn't imploded on itself yet)


I'm glad his rig is back up to snuff, but he's still pissed that they tried to sell him a line about the LSD, which he never really bought, but was willing to explore. Anywho, thanks for your help all. Oh, and I found out that they weren't Richmond gears...some other brand in 4.56. I'll ask him and post up...

it could be that they hear so much crap about noise from the lsd that they assumed thats what it was. they should have investigated more in the first place, but at least they owned up to it and made it right.