- Apply lubricant GM P/N 89021806 (Canadian P/N 89021807)
to each gear shift fork and gear shift head. Join the shift rail assembly to the input shaft and countershaft assembly.
 
- Install the input shaft, countershaft and shift rails
as an assembly in the clutch housing.
 
- Install the snap ring into the groove of the input shaft radial ball bearing.
 
- Install the snap ring into the groove of the countershaft radial ball bearing.
 
- Apply threadlocker GM P/N 12345382 (Canadian P/N 10953489) or equivalent to the
shift rail bolts.
 
Notice: Refer to Fastener Notice in the Preface section.
- Install the 4 shift rail bolts.
 
Tighten
Tighten the bolts to 21 N·m (15 lb ft).
Important: During alignment, ensure that the thread hole of the reverse idler gear shaft (204) aligns with the thread hole of the middle case.
- Apply lubricant GM P/N 89021806 (Canadian P/N 89021807) and install the following components:
 
| •  |  the reverse idler gear bearing (136) | 
 
| •  | the reverse idler gear (205) with the higher boss facing the rear | 
 
| •  | the reverse idler gear shaft (204) with its hole facing outward | 
 
- Apply lubricant GM P/N 89021806 (Canadian P/N 89021807)
and install the input shaft bearing (137), blocking ring (121) and the rear output shaft (111).
 
- Apply sealer GM P/N 89020326 (Canadian P/N 89021188) or equivalent to the interface
of either case.
 
- Install the shift shaft selector lever.
 
Notice: Refer to Machined Surface Damage Notice in the Preface section.
- Apply sealer GM P/N 89020326 (Canadian P/N 89021188) or equivalent to the interface of either case.
 
- Apply lubricant GM P/N 89021806 (Canadian P/N 89021807) to the shift and select lever shaft bearing.
 
- Install the intermediate case housing.
 
- Install the 8 bolts from the clutch housing and the 3 bolts from
the middle case.
 
Tighten
Tighten the bolts to 40 N·m (30 lb ft)
- Install the oil trough pipe (19).
 
- Install a NEW gasket (32) and the bolt (35) to secure the reverse idler shaft.
 
Tighten
Tighten the bolt to 40 N·m (30 lb ft)
- Install the oil trough (20) and the 2 oil trough bolts (37).
 
Tighten
Tighten the bolts to 8.5 N·m (75 lb in)
- Apply lubricant GM P/N 89021806 (Canadian P/N 89021807) to the following components:
 
| •  | the tapered roller bearing outer race | 
 
| •  | the cylindrical roller bearing | 
 
| •  | the control sub-assembly holes | 
 
- Apply lubricant GM P/N 89021806 (Canadian P/N 89021807) to the following components:
 
| •  | the tapered roller bearing of the output shaft | 
 
| •  | the cylindrical roller bearing inner race of counter gear | 
 
- Apply sealer GM P/N 89020326 (Canadian P/N 89021188) or equivalent to the interface of either case.
 
Notice: Refer to Machined Surface Damage Notice in the Preface section.
- Install the rear case housing.
 
- Install the 10 bolts (27) and retainer (209) to the rear case housing.
 
Tighten
Tighten the bolts to 40 N·m (30 lb ft)
- Apply lubricant GM P/N 89021806 (Canadian P/N 89021807) and install the lock ball
pin (68).
 
- Install the spring (75) and a NEW plug (36).
 
Tighten
Tighten the plug to 24.5 N·m (18 lb ft)
- Using 
J 35467 
 , install
a NEW clutch housing hole plug (30) into the clutch housing.
 
Tighten
Tighten the bolt to 39.3 N·m (29 lb ft).
- Using 
J 44731 
 , install
a NEW input shaft seal (12).
 
- Align and install the main shaft bearing oil slinger (107).
 
- Grease and install the locking ball (214).
 
- Align and install the vehicle speed sensor drive gear (212).
 
- Install a NEW rear output shaft rear bearing spacer (191).
 
- Apply sealer GM P/N 89020326 (Canadian P/N 89021188)
or equivalent to the interface of either case.
 
- Install the rear extension housing.
 
- Install the 8 bolts (93) into the rear extension housing (86).
 
Tighten
Tighten the bolts to 29 N·m (21 lb ft)
- Install a NEW select shift lever retainer (42), the damper (102) and shift lever rod universal
joint (40) into the end of the shift selector.
 
- Install the shift lever pin (41).
 
- With suitable pliers, rotate the shift lever retainer (42) backward.
 
- Stake the retainer (42) in place using pliers and 2 roll pins held in place with assembly lube.
 
- Install the propshaft flange (108).
 
- Grease and install a NEW propshaft flange fluid seal (193).
 
- Install a NEW propshaft flange nut (126).