For 1990-2009 cars

### Assembly Procedure

1. Use the scribe marks to align the synchronizer hub to the synchronizer sleeve.

Install the synchronizer hub and the three struts to the synchronizer sleeve.

2. Install the two spring retainers to the synchronizer hub.
3. Install the main drive synchronizer stop ring to the synchronizer sleeve and the synchronizer hub.
4. Install the drive sprocket to the mainshaft.
5. Install the synchronizer assembly to the mainshaft.
6. Install the synchronizer to the mainshaft snap ring.

### Installation Procedure

1. Install the input gear snap ring.
2. Apply RTV GM P/N 12345739 or equivalent on the bearing retainer mating surfaces.
3. Apply threadlocker GM P/N 12345382 or equivalent to the bearing retainer bolts.

Tighten
Tighten the input bearing retainer bolts to 19 N·m (14 lb ft).

Notice: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.

4. Install the following components into the rear case half:

4.1. | The oil pickup tube

4.2. | The oil tube connector

4.3. | The pump pickup screen

Important: Do not damage the O-ring during assembly.

This could result in pump failure.
5. Install the oil tube O-ring onto the oil pump pickup tube.
6. Install the shift lever O-ring and the plastic washer into the front case half.
7. Install the following components into the front case half:

7.1. | The shift lever

7.2. | The washer

7.3. | The nut

Tighten
Tighten the shift select lever nut to 27 N·m (20 lb ft).

8. Rotate as necessary to install the selector with the shaft into the front case half.
9. Install the range shift hub and the range shift fork into the front case half.

Rotate the selector in order to align the range shift fork.

10. Install the chain over the main shaft onto the drive gear.
11. Install the mainshaft assembly, the chain and the front output shaft into the case as an assembly.
12. Install the following components through the range shift fork and into the front case half:

12.1. | The mainshaft assembly

12.2. | The mode shift fork

12.3. | The rail

13. Install the front output shaft into the chain and into the front case half.
14. Use a soft faced hammer to install the planetary gear assembly through the input bearing into the annulus.
15. Install the fork shift spring onto the mode shift rail.
16. Install the oil pump to the oil pump pickup tube.
17. Apply RTV sealer GM P/N 12345739 or equivalent to the case mating surfaces.

Important: Do not damage the oil pump when installing the case halves together.

18. Install the rear case over the mainshaft and onto the front case half.
19. Install the two dowels.
20. Apply threadlocker GM P/N 13245382 or equivalent to the case bolts.
21. Install the case bolts into the case halves.

Place the two longer case bolts and washers into the doweled case holes, or into their original holes on the transfer cases with the attaching brackets.

Tighten
Tighten the case half bolts to 31 N·m (23 lb ft).

22. Install the snap ring behind the speedometer tone wheel to the mainshaft.
23. Install the speedometer tone wheel onto the mainshaft.
24. Install the snap ring in front of the speedometer tone wheel to the mainshaft.
25. Apply threadlocker GM P/N 12345382 or equivalent to the rear retainer housing bolt threads.
26. Install the rear retainer housing and the rear retainer housing bolts to the rear case half.

Tighten
Tighten the rear retainer housing bolts to 31 N·m (23 lb ft).

27. Install the output bearing snap ring to the mainshaft.
28. Apply RTV sealer GM P/N 12345739 to the extension housing mating surfaces.
29. Apply threadlocker GM P/N 1345382 or equivalent to the extension housing bolts.
30. Install the rear extension housing and the extension housing bolts to the rear retainer housing.

Tighten
Tighten the extension housing bolts to 31 N·m (23 lb ft).