Dodge D150 1990 Service Manual page 743

1 6 - 4 DRIVE SHAFTS AND UNIVERSAL JOINTS •
DRIVELINE VIBRATION CAUSES
D r i v e l i n e v i b r a t i o n can be caused b y t h e drive
shaft, d r i v e p i n i o n gear shaft (axle) yokes, U-joints,
or a n incorrect U-joint angle.
V i b r a t i o n caused b y the drive shaft(s) can be t h e
result of:
• undercoating m a t e r i a l on the drive shaft tube(s),
• missing drive shaft balance weight,
• excessive drive shaft " r u n o u t " ,
• w o r n o r damaged drive shaft yokes or U-joints,
• cracked seam welds a t either end o f t h e d r i v e shaft
tube, or
• dents o r bends i n t h e d r i v e shaft t u b e .
V i b r a t i o n f r o m the drive p i n i o n gear shaft (axle)
yoke can be the result of:
• excessive yoke " r u n o u t " ,
• loose clamp screws, or
• damaged yoke.
A n incorrect U-joint angle can produce a n out-
of-phase condition w i t h i n t h e U-joint t h a t results i n
v i b r a t i o n a t low or h i g h vehicle speeds.
DRIVELINE VIBRATION
Drive Condition
Possible Cause
Correction
DRIVE SHAFT VIBRATION a.
Undercoating or other foreign material a. Clean exterior of shaft and wash with
on shaft. solvent.
b. Loose U-joint clamp screws. b. Tighten screws properly.
c. Loose or bent U-joint yoke or excessive c.
Install replacement yoke.
runout.
d. Incorrect drive line angularity. d. Correct angularity.
e. Rear spring center bolt not in seat. e.
Loosen spring U-bolts and seat center bolt.
f.
Worn U-joint bearings. f. Replace U-joint.
9- Drive shaft damaged (bent tube) or out 9* Install replacement drive shaft..
of balance.
Install replacement drive shaft..
h.
Broken rear spring.
h. Replace rear spring.
i.
Excessive runout or unbalanced condition. i. Reindex drive shaft 180°, test and correct as
necessary.
i-
Excessive drive pinion gear shaft yoke
i-
Reindex drive shaft 180° and evaluate.
runout.
UNIVERSAL JOINT NOISE
a. U-joint clamp screws loose.
b. Lack of lubrication.
a. Tighten screws with specified torque.
b. Replace U-joint.
D r i v e l i n e v i b r a t i o n c a n a l s o r e s u l t f r o m l o o s e
o r d a m a g e d c r o s s m e m b e r s , s u p p o r t c u s h i o n s ,
l e a f s p r i n g s a n d d r i v e l i n e r e t a i n i n g b o l t s / n u t s .
R e f e r t o G r o u p 2 2 - T i r e s A n d W h e e l s f o r a d d i -
t i o n a l i n f o r m a t i o n i n v o l v i n g v i b r a t i o n d i a g n o s i s .
J9016-5
DRIVELINE VIBRATION DIAGNOSIS
W h e n a driveline v i b r a t i o n condition exists, do not
i n i t i a t e corrective action u n t i l t h e a c t u a l source of
the v i b r a t i o n has been identified. T h i s i s very impor-
t a n t i f unnecessary or ineffective repairs are t o be
avoided. T h e following diagnosis charts w i l l help to
identify t h e most common causes o f d r i v e l i n e v i b r a -
tion.