RE: Vibration in Chassis (very very long post)

From: Bernd D. Ratsch (bernd@texas.net)
Date: Sun Oct 26 2003 - 01:34:57 EDT


Have you looked at the driveline vibration TSB (been out since 1998).

- Bernd

-----Original Message-----
From: owner-dakota-truck@bent.twistedbits.net
[mailto:owner-dakota-truck@bent.twistedbits.net] On Behalf Of Dale Schultz
Sent: Saturday, October 25, 2003 6:29 PM
To: dakota-truck-moderator@bent.twistedbits.net
Subject: Re: DML: Vibration in Chassis (very very long post)

Tony Cellana wrote:
> Another possibility I forgot to mention is pinion angle. If the
> pinion angle is off, it can cause some movement and/or binding in the u
joints.
> Not sure what the specs are on pinion angle for the truck. If it is off
> from ideal, pinion angle shims can be purchased, and installed between
> the axle and spring.
>
> TonyC
>
Hi:
I used a steel protractor and a small bubble level to measured this. I
forgot to put the info in the original post.
At the transfer case yoke I measured 8 degrees clockwise from vertical. At
the transfer case on the drive shaft, 8.5 degrees from vertical. At the
pinion yoke, 6.5 degrees from vertical.

 From what is in the Field Service Manual an angle under 5 degrees is
acceptable for a shaft that spins up to 3500RPM.
My angle calculates as:
Front: 8-8.5 = -0.5
Rear: 8.5-6.5 = 2.0
Final angle difference: 2.0-0.5 = 1.5 degrees

The FSM also indicates that GOOD cancellation is within 1 degree and
that there should be at least 0.5 degrees of continuous operating angle.

I think mine is okay except for the fact that the angle at the front and
the rear are not that close to each other to cancel out the phasing of
the shaft. Maybe the transmission mount has settled some causing the
angle at the front to drop. I could replace the mount or shim the axle
1 degree.

Anyone know what the typical angles are on a one-piece drive shaft?

I'm pretty sure that I have either a drive shaft run-out problem or the
pinion bearings are worn (possibly due to a drive shaft run-out problem).

Thanks.
Dale



This archive was generated by hypermail 2b29 : Fri Feb 06 2004 - 11:47:04 EST