Dodge RAM TRUCK 1500 1995 Service Manual page 268

B R
CLUTCH 6-19
CAUTION: .Never use water, or compressed air t©
cool the flywheel. The rapid cooling produced by
water or compressed air can distort, or crack the
gear and flywheel.
CHECIili 114111 CLUTCH HOUSING RUNOUT
Only t h e NV4500 clutch housing c a n b e
checked using t h e following bore and. face
runout procedures. The NV3500 clutch housing
is a n integral p a r t of t h e transmission front
case a n d c a n only be checked off t h e v e h i c l e .
MEASURING CLUTCH HOUSING BORE
RUNOUT (NV4S00 ONLY)
(1) Remove the clutch housing and strut.
(2) Remove the clutch cover and disc.
(3) Replace one o f t h e flywheel bolts w i t h a n ap­
propriate size threaded rod t h a t is 10 i n . (25.4 cm)
long (Fig. 21). The rod w i l l be used to mount the dial
indicator.
(4) Remove the release fork from the clutch hous­
ing.
(5) Reinstall the clutch housing. Tighten the hous­
i n g bolts nearest t h e alignment dowels first.
(6) M o u n t the dial indicator on t h e threaded r o d
and position the indicator plunger on t h e surface of
the clutch housing bore (Fig. 22).
(7) Rotate the crankshaft u n t i l t h e indicator
plunger is a t the top center of the housing bore. Zero
the indicator at this point.
(8) Rotate the crankshaft and record the indicator
readings at eight points (45° apart) around t h e bore
(Figs. 21-22). Repeat the measurement at least twice
for accuracy.
(9) Subtract each reading from t h e one 180° oppo­
site to determine magnitude and direction of runout.
Refer to Figure 23 and following example.
Bore runout example:
0.000 - (-0.007) = 0.007 in.
+0.002 - (-0.010) = 0.012 in.
+0.004 - (-0.005) = 0.009 in.
-0.001 - (+0.001) = -0.002 in. (= 0.002 inch)
I n t h e above example, the largest difference is
0.012 i n . and is called the total indicator reading
(TIR). This means t h a t the housing bore is offset
from the crankshaft centerline by
0.006
i n . (which is
1/2 of 0.012 in.).
On gas engines, the acceptable m a x i m u m T I R for
housing bore runout is 0.010 inch. I f measured T I R is
more t h a n 0.010 i n . (as i n the example), bore r u n o u t
w i l l have to be corrected w i t h offset dowels. Offset
dowels are available i n
0.007, 0.014
and
0.021
i n .
sizes for this purpose (Fig. 23). Refer to Correcting
Housing Bore Runout for dowel installation.
On diesel engines, the acceptable maximum
TIR for housing bore runout is 0.015 inch. How­
ever, unlike gas engines, offset dowels are not
available to correct runout on diesel engines. If
bore runout exceeds the stated maximum on a
diesel engine, it may be necessary to replace ei­
ther the clutch housing, or transmission
adapter plate.
CORRECTING CLUTCH HOUSING BORE
RUNOUT (NV4S00 GAS ENGINE ONLY)
On gas engine vehicles, clutch housing bore runout
is corrected w i t h offset dowels. However, i f bore
r u n o u t exceeds 0.015 i n . T I R on a diesel equipped
model, t h e clutch housing, or transmission adapter
plate m a y have to be replaced. Offset dowels are not
available for diesel models.
The dial indicator reads positive when the plunger
moves i n w a r d (toward indicator) a n d negative when
i t moves outward (away from indicator). As a result,
the lowest or most negative reading determines the
direction of housing bore offset (runout).
I n t h e sample readings shown i n Figure 24 and i n
step (7) above, t h e bore is offset toward t h e 0.010
inch reading. To correct this, remove the housing and
original dowels. Then install the new offset dowels i n
the direction needed to center t h e bore w i t h t h e
crankshaft centerline.
I n t h e example, T I R was 0.012 inch. The dowels
needed for correction would have a n offset of
0.007
i n . (Fig.
24).
I n s t a l l t h e dowels w i t h the slotted side facing out
so they can be t u r n e d w i t h a screwdriver. Then i n ­
stall t h e housing, remount t h e dial indicator and
check bore r u n o u t again. Rotate the dowels u n t i l t h e
T I R is less t h a n 0.010 i n . i f necessary.
I f a T I R o f
0.053
i n . or greater is encountered, i t
may be necessary to replace the clutch housing.
7/16 - 20 THREAD NUT
^ 10 INCHES L O N G - •—^
J9Q06-25
Fig. 21 Dial Indicator Mounting Stud Or Rod
MEASURING CLUTCH HOUSING FACE
RUNOUT (NV4500)
(1) Reposition the dial indicator plunger on t h e
housing face (Fig. 25). Place the indicator plunger at
the r i m of the housing bore as shown.
(2) Rotate the crankshaft u n t i l the indicator
plunger is a t the 10 O'clock position on the bore.
Then zero the dial indicator.