768C TRACTOR & 769C TRUCK POWER TRAIN DISASSEMBLY & ASSEMBLY Caterpillar

Transmission Governor

Usage:

Disassemble Transmission Governor

start by:

a) remove transmission governor

1. Remove O-ring seals (3) from the cover.

2. Remove bolt (2), washers and idler gear (5) from the cover. Remove the bearing from gear (5).

3. Remove O-ring seal (4), washer and governor housing (1) from the shaft.

NOTE: Make a note of the location of the governor parts so the governor will be assembled correctly.

4. Remove snap rings (6) that hold the reducing valve spools A, B and C in the governor housing.

5. Remove the stops and reducing valve spools from the governor housing.

6. Remove slug (7) from valve spool (8) of reducing valve A.

7. Remove snap ring (9), spacers (10) and slug (11) from valve spool (12) of reducing valve (B).

8. Remove snap ring (13) and spacers (14) from valve spool (15) of reducing valve (C).

9. Remove spiral snap ring (16) and gear (17) from the governor housing.

10. Remove washer (20) and shaft (18) from the cover.

11. Remove bearing (19) from the cover.

12. The governor shaft is installed to an exact depth. For assembly purpose remove the plug from the cover and install a 9/16"-18 NF bolt (21) that is two in. long with a nut on it. Install the bolt until it makes contact with the governor shaft. Use the nut to hold the bolt in this position. Use bolt (21) as a stop when the governor shaft is installed.

13. Use tooling (A) to remove the governor shaft.

14. Remove the setscrews from the end of the governor shaft. Clean the oil passages in shaft.

Assemble Transmission Governor

1. Put 9S3263 Thread Lock on the threads of the setscrews and install the two setscrews in the end of governor shaft (1).

2. Lower the temperature of the governor shaft and install it in the cover until it makes contact with the stop bolt that was installed in the cover.

3. Use tool (A) to measure the distance from the end of the shaft to the finished face of the cover. The distance must be 4.969 ± .005 in. (126.213 ± 0.127 mm).

4. Remove the stop bolt and install the plug in the cover.

5. After the shaft is installed in the cover, check the shaft for internal leaks. Use tool (B) and an air nozzle. Put air through the "A" pressure passage in the cover to find the "A" pressure groove in the governor shaft. Put an O-ring seal and hose clamp (2) around the "A" pressure groove in the shaft. Put air pressure on the "A" pressure passage in the cover. Put liquid soap around the shaft as shown or put the cover and shaft under water and check for air bubbles. If you see air bubbles come out of the open grooves, the shaft has a leak and a replacement must be made. If you see air bubbles come out where the shaft goes into the cover, the hole in the cover has been made larger when the shaft was removed and a replacement of the cover must be made. Do this check for the other two circuits. After the checks are done use air pressure to get all of the water out of the shaft and cover.

6. Use tooling (C) to install the bearing in the cover until it is .02 in. (0.51 mm) below the top surface of the hole.

7. Install slug (3) in valve spool (4) of reducing valve A.

8. Install slug (7), spacers (6) and snap ring (5) in valve spool (8) of reducing valve B.

9. Install spacers (10) and snap ring (9) in valve spool (11) of reducing valve C.

10. Install reducing valve spools A, B and C in governor housing (14) according to the letters A, B and C on the housing.

11. Install stop (12) and snap ring (13) that holds each reducing valve spool in the governor housing.

12. Install gear (15) on the governor housing with the key groove in alignment with key (16) in the governor housing. Install the spiral snap ring that holds the gear in place.