Re: Drive-train/tranny diagnosis?

["Russ Maki" <rinard@xxxxxxxxxx>]

Drew,
Could be your driveshaft center bearing on its way out...the bearing sound
is most noticeable at lower speeds, IME. As the bearing becoms worse you may
get an increase in driveshaft vibration, if that's the problem.

Replacement is a moderate-skill DIY project if you've got the Bentley
manual -- and you might as well replace the flex disc and transmission
mounts while you have the driveshaft out. Unfortunately, you'll have to drop
your newly-installed exhaust.

To check the bearing, look under the car and determine its location along
the driveshaft tunnel. Then get a cheap mechanic's stethescope and have
someone else drive the car while you listen along the driveshaft tunnel from
the back seat. You should be able to tell easily if the noise is coming from
the area of the bearing.

BTW, I had a K&N air filter in car and took it out. Too bad you didn't try
to buy one on the mailing list; I bet you could have found a lot of cheap
second-hand ones!
Russ
'87 325ic



> Date: Sat, 16 Dec 2000 19:19:38 -0600
> From: Drew Mouton <drew@domain.elided>
> Subject: Drive-train/tranny diagnosis?
>
> Hello All,
>
> More interesting problems as I work my way through rebuilding my
> daily-driven '87 325iC.
>
> At the beginning of the week I started hearing a high-pitched, fast-paced
> chirping sound on accelleration from stop up thru about 10-15 mph. As I
> accellerate it evolves into more of a rattle (which I can feel thru the
> center console of the car) then seems to go away as I speed through 20mph
> or so. No noticeable problem at highway speeds.
>
> This seems to only happen when in gear (ie no problems if I rev the
> engine in neutral), doesn't seem to exist in reverse gear, the _pace_ of
> the chirp doesn't seem to change based on speed - meaning it sounds about
> the same at 5mph as it does at 10 - and it has gotten progressively
> worse.
>
> FWIW, tranny fluid is fine, same color as when I put it in 3 months ago.
>
> I feel like I should know what this indicates, but I'm drawing a blank.
> Would anyone care to make suggestions before I start spending a lot of
> time ruling things out?
>
> Thanks much.
>
> Drew

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