Re: Rear End Growl

From: Sam Parthemer (srp@home.com)
Date: Wed Dec 03 1997 - 21:03:29 EST


-----Original Message-----
From: Rader <rlr@bbt.com>
To: Dakota Mailing List <dakota-truck@buffnet.net>
Date: Tuesday, December 02, 1997 7:15 AM
Subject: DML: Rear End Growl

>Well, I've been having loads of fun taking my '95 back and forth between
>work and two dealers in order to get a rear end growl fixed under 3/36
>warranty. Figured I'd ping this august group to see if anyone else had the
>same problem.
>
> About 3 months ago, I started noticing a bizarre growl coming from the
>rear of the Dakota (thought it was a low-flying airplane at first ;).
>I admit it's not very loud, but it is most pronounced while coasting around
>40 mph, and has the unmistakable characteristics of a failing bearing.
>
> Since I absolutely despise taking any of my beloved vehicles to anyone
>else for work, I did everything I could think of to isolate the noise and
>convince myself it was time for warranty repair (change tire pressure,
>rotate tires, see if noise is affected by turns, etc.). Finally decided
>it was the rear end after I put it up on jack stands, cranked it up to
>60 mph, and ran under the truck while coasting (OK, not the safest
procedure,
>but I was careful). Noise definitely coming from input pinion shaft
>or U-joint yoke area. FSM leads me to believe it's the front bearing at
>fault (loudest while coasting, though it is starting to happen while
>under power). Noise not affected by turns at all, so I doubt it's the
>differential, and it doesn't sound like gear noise anyway.
>
> The service dudes crack me up. I've driven with one, who agreed there
>was a noise, but next week when they supposedly put it up on the rack,
>claimed there wasn't any problem. Squirted a tube of friction modifier
>in there to shut me up, as if that would have any effect on a bearing
>noise (it didn't). Another dealer tried to blame it on tire noise, let
>alone the fact I explained my debugging procedure in detail. Mind you,
>each of these little visits requires a 60 mile round trip (two so far,
>third on the way).
>
> Anyway, I know a couple of you have experienced rear end problems
(careful
>there, I'm talking about your Dakota ;), particularly Sam P. Could you
>explain what happened, so I have a better idea of what failure I'm
potentially
>facing? I'm getting real tired of watching service tech eyes glaze over
>when I try to explain my diagnosis.
>
> This is a '95 CC 5.2 5-speed with the 3.55 limited slip differential.
>No obvious TSBs in Alldata.
>
> Once again, I am left convinced that dealer service techs are the worst
>mechanics in existence. Strike that; they aren't mechanics, they're
patsies
>for the dealers' corporation. All that ASE-and-factory-certified crap they
>jam down your throat is marketing, and nothing more.
>
> Ron "Trying To Be A Nice Guy, But Quickly Losing Patience" Rader
>
>

    Here's what happened to me:

    I drove too far on the OEM lube, roughly 65000 miles. I was driving one
day
at highway speeds, and noticed a faint growl/whine from the truck while
under
load/and decel under engine braking. I am very particular about
creeks/groans/
chirps/clips/chips/you name it. So I opened my slider, and with a shell on
it
was quite loud, and apparent.

    I drove it to my local trans/diff mechanic who did my jeep for me. Not
exactly cheap, and I did have to take the jeep back a few times to fix
his mistakes-- but they did take care of me.

    I took it for a drive with the greasiest mechanic they had, and he
proceeded
to have me try a few things while driving (hold a gear at 3500 rpm and go up
to 4000 and back to 3500...) and was convinced that it was bearing noise.

    So I didn't drive the truck more than another 30 miles before I had them
tear into it.

    One of the races had 'spalling' on it, is what they told me. I got the
old
bearings, and was able to see a spot on the race that looked like the
metal had 'melted' in a spot, and run down a bit. Every revolution of the
bearing over this 'melted spot', caused the noise I was hearing. If I'd
kept driving, eventually the bearing would have completely failed, causing
more damage.

    If you could, get a local diff. shop take a test drive with you to see
if they
have any clues.

    Ended up costing me $450.00 parts & labor, which included changing the
transmission fluid (5 spd-- very expensive!), new bearings, new rear fluid,
and the additive for the limited slip diff.

    Hope this helps!

    Sam '95 SLT



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