First, the specs:
5.9L SLT, 4WD, 30/10.5R15 (stock option) tires, 160k+ miles, front/rear positrack/limited slip differentials.

The problem:
Makes an awful grinding/growling noise during low speed manuevering, such as a parking lot or city driving in 2WD mode. The noise is accompanied by a vibration throughout the vehicle (can be felt moreso in the steering wheel than the floorboards/seats).

The oh so nice Goodyear yokels insist this is a normal thing for the model, which I highly doubt.

The front end was completely rebuilt (joints, bushings, the whole nine) last year. I haven't had the time until now to get it in the air on a lift to have a look myself (currently in Tech School) so I have no idea if they seriously flubbed something or not.

It's my ma's truck, and she believes that her usual shop -across the street from her work- has no clue what they're doing. I don't know -and really don't believe- that they put the Lube Modifier in the differentials at the last service as they insist that the identification tags are missing/damaged and that it's not equipped with limited slip gearing.

I was there when it was ordered at the dealer, so I know better.

Dunno if it's related either way -as a cause or a result of the vibrations- but the ABS computer fried some time ago (Goodyear blames "oversized tires" for that one, saying the computer wasn't programmed for them; again a load of fertilizer). With that indicator on, the red "BRAKE" light is also permanently lit for some reason or another.

Ideas/suggestions? I'll be putting it on the lift relatively soon.

 

Someone feel few to correct me but the front end doesn't have limited slip option. The diff isn't strong enough. The rear may have one. Post the vin and we can check that. Have you checked the wheel bearing/hub? What year is the truck?

 

NvM just saw the year in the title

 

It's a '98, hasn't seen off-road use at all nor has it pulled anything bigger than a car trailer. The bearings are fine, as the noise/vibrations go away in a straight line and the stability is good up to 70 MPH. The steering is as responsive as the day it was driven off of the dealer's lot.

There's no popping or pinging when going over dips, bumps or the like (there is a slight bushing squeal, but nothing to write home about).

It had been in a minor accident back in 2002ish, but I really doubt a problem like this would take a decade to show up.

As for the VIN . . . give me a resource to do a look up and I'll do it myself. It's a combination of trust issues (my ma and I are private people) and I'm thinking of using this experience as a learning tool for my Auto/Diesel tech classes I'm taking.

 

have a look at the cv boots and make sure they look alright. If you say the suspension is alright it doesn't leave much other than the steering and the driveline

 

go to dodge.com/owners, send a request with the VIN to them asking for a build sheet, they will email one to you in a day or two.

i would just check for limited slip the old fashioned way, put the truck up in the air and spin the back tires, if they spin in opposite directions its an open diff if they spin together its a lsd, as stated above no LSD in the front the front diff.

have you checked the balance on the tires? i have seem that be the culprit of may different vibrations

 

Not the balance either, as the tires are wearing evenly (no cupping, excessive shoulder/center wear, the whole nine). The grind/vibration only happens during low speed manuevering in either direction.

I took a gander at the rear leaf's and the right side is no longer in alignment; the axle leaf (short little guy that doesn't reach the shackles) is slightly aiming to the left, enough to see with the naked eye at any rate.

One thing I have noticed with this problem, every now and again the front diff acts like it's trying to engage in 4WD mode as I can feel the jerk a four-by makes on dry surfaces.

Once I get it in the air I plan on checking the CVs, driveshafts/U-joints front and rear, fluid level of the diffs (and I mean really take a look, especially for metal shavings), engine/trans/TC mounts, double check the bearings, spring mounts/bushings . . . well, let's just say the entire undercarriage.

Since I saw the thread on the ABS/BRAKE M.I. lights, the sensors in the rear diff and front knuckles are on my list of things to do.

Thanks for the heads-up on the build sheet, that'll help with any diagnostics/repairs I need to recommend to my ma.

 

When was the last time the rear diff oil was changed? I'd start by changing it. Make sure to add friction modifier (it's required per the service manual). The older formulations of friction modifiers break down over time. When it breaks down, it can destroy your lsd and make it growl at low speeds. May sound crazy but I speak from experience (fortunately mine was not destroyed).

 

Aight, the build sheet is in . . . and it's a doozy. Now that I'm more technically savvy some of these options reach out and slap me in the face, such as:

DHKP Shift-on-the-Fly,231HD Transfer Case
DJLS 175MM Front Axle
DMHP 3.92 Rear Axle Ratio
DRBP Corporate 9.25 LD Rear Axle
DSA Anti-Spin Differential Rear Axle
TUT 31X10.5R15 OWL All Season Tires (Read my spiel on Goodyear)

So, the rear Limited Slip is there. Is that 175mm front end a troublemaker? I've come across a few posts where people have complained about it.

 

the front end is usually fine for normal driving, if the truck is stock that is not where i would look for the problem, however if the truck has been off-roaded and beat on then it is likely.