Clutch Housing Bore Runout
CLUTCH HOUSINGThe clutch housing maintains alignment between the crankshaft and transmission input shaft. Misalignment can cause clutch noise, hard shifting, incomplete release and chatter. Also premature pilot bearing, cover release fingers and clutch disc wear. In severe cases, it can cause premature wear of the transmission input shaft and front bearing.
NOTE: Only the NV4500 clutch housing can be checked using the following bore and face runout procedures. The NV5600 clutch housing is a integral part of the transmission and can only be checked off the vehicle.
CLUTCH HOUSING BORE RUNOUT
CAUTION: On diesel engines if housing bore runout exceeds 0.015 inch, the clutch housing/transmission adapter plate must be replaced. On gas engines if housing bore runout exceeds 0.053 inch the clutch housing must be replaced.
NOTE: Offset dowels are available for gas engines to correct housing bore runout. They are not available for diesel engines.
1. Remove the clutch housing and strut.
2. Remove the clutch cover and disc.
3. Replace one of the flywheel bolts with an appropriate size threaded rod that is 10 inch (25.4 cm) long (Fig. 11). The rod will be used to mount the dial indicator.
4. Remove release fork from the clutch housing.
5. Install clutch housing. Tighten the housing bolts nearest the alignment dowels first.
6. Mount dial indicator on the threaded rod and position indicator plunger on the clutch housing bore (Fig. 12).
7. Rotate crankshaft until indicator plunger is at the top of the housing bore. Zero the indicator at this point.
8. Rotate crankshaft and record indicator readings at eight points (45°apart) around the bore (Fig. 13). Take measurement at least twice for accuracy.
9. Subtract each reading from the one 180° opposite to determine runout and direction.
Bore runout example (Fig. 13):
0.000 - (-0.007) = 0.007 inch
+ 0.002 - (-0.010) = 0.012 inch
+ 0.004 - (-0.005) = 0.009 inch
- 0.001 - (+0.001) = -0.002 inch
In this example the largest or Total Indicator Reading (TIR) difference is 0.012 inch. This means the housing bore is offset from the crankshaft centerline by 0.006 inch which is 1/2 of 0.012 inch. The dowels needed to correct this have an offset of 0.007 inch (Fig. 14).
Remove housing and install dowels with the slotted side facing out so they can be turned with a screwdriver. Then install the housing and mount the dial indicator and check bore runout again. Rotate the dowels until the TIR is less than 0.010 inch.