99 T&C All Wheel Drive Noise

The vehicle is a 99 T&C Limited with All Wheel Drive, currently with
170,000 miles. Seven years ago with only 30K on the van, it developed a
siren like noise under the middle of the body. With the windows open,
you would swear that an emergency vehicle was right on your rear bumper.
Chrysler replaced, under warranty, a "SOP Front Torque Tube Bearing"
(6 parts used). There was some mention of a Viscous Clutch.

Can someone tell me what that all meant? The sound has returned! It is
noticeable starting about 5 MPH and increased with speed. Other vehicle
noises drown it out above about 30. How much should I expect to pay for
the repair, and is this a dealer only function? This vehicle is not yet
ready for the bone yard, I hope. Is a failure of this item
catastrophic, or just inconvenient?

 

The failure of the bearing will be catastrophic when it really gets messed
up good. You won't be driving it. \

The system has an overrunning clutch (it's a one-way clutch, like a ratchet,
but it doesn't click) and it also has a viscous coupling that drives the
rear axle. The viscous coupling itsn't a clutch. It's a coupling that
transfers torque though some gooey liquid. This allows the rear to slip in
relation to the front. That's a good thing. I cannot think of anything in
the system offhand that would have initial SOP, so that didnt' help me.

I never had to replace a bearing on mine, so I couldn't comment on what it
looks like, but most of the time bearings are pretty simple and they're
intended to be replaced. It might be a bearing you can get at a bearing
supplier for $10, or it might be dealer only. It really depends on how it
was made, and I couldn't say about that.

 

By gaging the seriousness of the bearing failure, I was trying to get a
handle on, is this going to cause an accident when it happens? "You
won't drive it" is not what I would consider catastrophic.

 

The parts used for the repair below were:
4518551 Retainer 9039016
4641578 Shield to 21003028
4641756 Plate Vis 21133038
4518903 Nut Ptw F 21009036
4486164 Bearing F 21005001
4773590 Fluid Aut 1081018

1.6 hours of Tech time

 

I've got a 1994 T&C AWD. Let be explain a bit about these AWDs, the design
is really stupid. The so-called "torque tube" is nothing more than a
driveline, however
instead of the normal driveline, Chrysler put in something similar to a CV
axle, with
boots and a CV joint where the U-joints on a driveline normally should be.

What has probably happened with yours is one or both of the boots on the
driveline has split. What happens is the CV joints in these things wears
out, then
they start rattling and banging all over at the joint, the boot then splits
open and
slings out the remaining grease and the torque tube vibrates worse and
worse.
This destroys the bearings in the power transfer case in the front and the
slipping
clutch in the back.

If yours has 170K on the original driveline the driveline is probably shot.
The
shitty part about this is that a lot of the parts for these are now
unavailable so
it is a real hit and miss if a driveline place can rebuild it. The shot
driveline
probably took the bearing with it.

Get under the vehicle and inspect the driveline boots to make sure they are
intact. If they aren't then one option is to simply remove the driveline.
With
the bearing in the front power transfer case now unloaded, it won't whine
anymore. Of course you lose the AWD but so what?

Ted