I just did this.
Even though it is a simple job, I figured a short writeup and pictures might be useful to someone someday.
Please make additions or corrections if you can.
TOOLS REQUIRED:
Wrench and sockets, with a small (4-5 inch) extension.
Snap ring pliers
Plastic hammer
Brass drift
A 3/4 inch PVC fitting of your choice (SST)
1/2 inch wooden dowel
PARTS AND MATERIALS:
Transfer case rear output seal
Appropriate sealant (RTV silicone)
2 quarts 80 w90 gear lube.
PROCEDURE:
1. Remove the rear drive shaft.
2. Clean the top of the transfer case to remove any dirt and grime that could fall into the open case.
3. Unplug the speedometer sensor cable and the two plugs on top of the transfer case.
4. Remove the 9 bolts holding the rear extension housing on the transfer case.
**The extension will probably not fall off--it's still "glued" on.
5. Although the extension is not very heavy, another set of hands would be helpful when removing the extension housing. Use your plastic hammer to tap the housing free of the transfer case. You may need to tap the back to get it free--there is a tab on the passenger side of the housing that you can get to with a brass drift and hammer.
**There is a small (~3 inch diameter) spacer ring in the upper passenger side (pump?) area of the transfer case. It is not secured, and could fall out. Watch for it.
6. The big cylindrical object in top of the extension housing is the viscous coupler. There is a snap ring inside at the base of the exposed output shaft. It is a very tight fit for pliers. I didn't think my Sears snap ring pliers would work, but after a few tries, I found that they would fit if I inserted them slightly open. I expect that most snap ring pliers SHOULD fit, don't give up prematurely.
Remove the snap ring.
7. Pull out the viscous coupler.
8. Remove the three bolts holding the pump plate and shield thingy (name?). Remove the shield and lift the pump plate off of the shaft. The plate is tight, but I was able to remove it with one finger and one piece of bent wire inserted into one of the bolt holes.
**When the plate is fully seated, it spins. Remember this when you're reassembling.
**At this point you will notice the speedometer sensor gear at the bottom of the housing. You don't have to remove this, as long as your are reasonably careful.
10. Remove the snap ring on the shaft at the top of the speedometer drive gear.
11. Remove the speedometer drive gear (the one on the shaft that drives the sensor gear).
12. Remove the snap ring at the base of the output shaft, below the speedometer sensor gear. You could fish it out past the speedo sensor, or you could let it come out when you remove the shaft.
13. Using your PVC Special Service Tool or similar, unseat the output shaft with a few civilized whacks.
14. Carefully remove the shaft from the housing--watch out for your speedo sensor if you left it in.
15. The output seal is on the bottom of the extension housing. Use a screwdriver or seal puller to remove the old seal.
16. Use your plastic hammer to carefully seat the new seal. The wooden dowel can be used as a drift. The seal does not seat incredibly tight--nothing like the inner axle seal--but it is all rubber, be gentle.
17. Reassemble the housing in the reverse order.
18. Remove all the old sealant and clean the extension housing and transfer case mating surfaces with brake cleaner or similar.
19. Apply a small (~1/8 inch) bead to the mating surface of the extension housing.
20. Put 'er back on.
**Don't forget the spacer ring on the pump. I oiled it up with gear lube so it would stick to the pump while I put the extension back on.
21. Put the drive shaft back on and reattach the three plugs.
22. Crack a cool beverage
. I prefer cheap beer when working in the garage.
22. Wait overnight for the sealant to cure before refilling the transfer case.
23. Don't forget to refill the transfer case.
Hayes
Even though it is a simple job, I figured a short writeup and pictures might be useful to someone someday.
Please make additions or corrections if you can.
TOOLS REQUIRED:
Wrench and sockets, with a small (4-5 inch) extension.
Snap ring pliers
Plastic hammer
Brass drift
A 3/4 inch PVC fitting of your choice (SST)
1/2 inch wooden dowel
PARTS AND MATERIALS:
Transfer case rear output seal
Appropriate sealant (RTV silicone)
2 quarts 80 w90 gear lube.
PROCEDURE:
1. Remove the rear drive shaft.
2. Clean the top of the transfer case to remove any dirt and grime that could fall into the open case.
3. Unplug the speedometer sensor cable and the two plugs on top of the transfer case.
4. Remove the 9 bolts holding the rear extension housing on the transfer case.
**The extension will probably not fall off--it's still "glued" on.
5. Although the extension is not very heavy, another set of hands would be helpful when removing the extension housing. Use your plastic hammer to tap the housing free of the transfer case. You may need to tap the back to get it free--there is a tab on the passenger side of the housing that you can get to with a brass drift and hammer.
**There is a small (~3 inch diameter) spacer ring in the upper passenger side (pump?) area of the transfer case. It is not secured, and could fall out. Watch for it.
6. The big cylindrical object in top of the extension housing is the viscous coupler. There is a snap ring inside at the base of the exposed output shaft. It is a very tight fit for pliers. I didn't think my Sears snap ring pliers would work, but after a few tries, I found that they would fit if I inserted them slightly open. I expect that most snap ring pliers SHOULD fit, don't give up prematurely.
Remove the snap ring.
7. Pull out the viscous coupler.
8. Remove the three bolts holding the pump plate and shield thingy (name?). Remove the shield and lift the pump plate off of the shaft. The plate is tight, but I was able to remove it with one finger and one piece of bent wire inserted into one of the bolt holes.
**When the plate is fully seated, it spins. Remember this when you're reassembling.
**At this point you will notice the speedometer sensor gear at the bottom of the housing. You don't have to remove this, as long as your are reasonably careful.
10. Remove the snap ring on the shaft at the top of the speedometer drive gear.
11. Remove the speedometer drive gear (the one on the shaft that drives the sensor gear).
12. Remove the snap ring at the base of the output shaft, below the speedometer sensor gear. You could fish it out past the speedo sensor, or you could let it come out when you remove the shaft.
13. Using your PVC Special Service Tool or similar, unseat the output shaft with a few civilized whacks.
14. Carefully remove the shaft from the housing--watch out for your speedo sensor if you left it in.
15. The output seal is on the bottom of the extension housing. Use a screwdriver or seal puller to remove the old seal.
16. Use your plastic hammer to carefully seat the new seal. The wooden dowel can be used as a drift. The seal does not seat incredibly tight--nothing like the inner axle seal--but it is all rubber, be gentle.
17. Reassemble the housing in the reverse order.
18. Remove all the old sealant and clean the extension housing and transfer case mating surfaces with brake cleaner or similar.
19. Apply a small (~1/8 inch) bead to the mating surface of the extension housing.
20. Put 'er back on.
**Don't forget the spacer ring on the pump. I oiled it up with gear lube so it would stick to the pump while I put the extension back on.
21. Put the drive shaft back on and reattach the three plugs.
22. Crack a cool beverage
. I prefer cheap beer when working in the garage. 22. Wait overnight for the sealant to cure before refilling the transfer case.
23. Don't forget to refill the transfer case.
Hayes
Last edited:
Sorry! But at least your driveway will thank you 
