Extension Housing & Mainshaft

Except Overdrive Units

Fig. 3 Center Bearing Snap Ring Compression:

Fig. 4 Clutch Gear Snap Ring Removal:

Fig. 5 Centergear Endplay Measurement:

1. Remove bolt and retainer securing speedometer pinion adapter in extension housing, then the adapter and pinion from housing.
2. Remove extension housing attaching bolts.
3. Slide 3rd-4th synchronizer sleeve slightly forward, slide reverse idler gear to center of shaft, then using a mallet, tap extension housing rearward. Slide extension housing and mainshaft assembly from case.
4. Remove snap ring retaining 3rd-4th synchronizer clutch gear and sleeve assembly, then slide assembly from mainshaft.
5. Slide 3rd speed gear and stop ring from mainshaft.
6. Compress snap ring retaining mainshaft ball bearing in extension housing and pull mainshaft assembly and bearing from extension housing, Fig. 3.
7. Remove mainshaft bearing retaining snap ring. Remove bearing by installing steel plates on the 1st speed gear, then press or drive mainshaft through bearing. Use caution not to damage gear teeth.
8. Remove bearing, bearing retainer ring, speed gear and 1st speed stop ring from shaft.
9. Remove 1st-2nd clutch gear and sleeve assembly snap ring, Fig. 4, then slide assembly and the 2nd speed gear from shaft.
10. Measure countershaft gear end-play by inserting a feeler gauge between thrust washer and gear, Fig. 5. End-play should be 0.015"-0.029". If not, install new thrust washers when reassembling transmission.

Overdrive Units
1. Remove bolt and retainer securing speedometer pinion adapter in extension housing, then the adapter and pinion from housing.
2. Remove extension housing attaching bolts.
3. Rotate extension housing on output shaft to expose the rear of countershaft. Clearance is provided on extension housing flange to permit one bolt to be reinstalled to hold the extension housing in the inverted position for access to countershaft.
4. Drill a hole in the countershaft expansion plug at front of case. Then, working through hole, push countershaft rearward until woodruff key is exposed and remove key. Push countershaft forward against expansion plug and using a brass drift, tap countershaft forward until expansion plug is driven from case.
5. With a dummy shaft, drive countershaft through rear of case, using caution so the countershaft washers do not fall out of position. Lower cluster gear to bottom of case.
6. Rotate extension housing back to normal position.
7. Remove drive pinion bearing retainer attaching bolts, then slide retainer attaching bolts, then slide retainer and gasket from pinion shaft. Pry pinion or seal from retainer. Use caution not to nick or scratch seal bore in retainer or the surface on which the seal bottoms.
8. With a brass drift, drive the pinion and bearing assembly through the front of case.
9. Perform steps 3 through 9 as described above under Except Overdrive Units.