Arctic Chat : Arctic Cat Forum banner
1 - 3 of 3 Posts

338 Posts
Discussion Starter · #1 ·
ATV: 2004 400 Manual FIS
Problem: Rear pinion seal was leaking
Fix: Replaced the rear pinion bearing, seal, rear drive shaft boot, and pinion housing/diff gasket.
Procedure: *Numbers in ( ) are socket/wrench sizes

Note 1: It may be possible to complete this repair without performing steps 1-5

Note 2: Place the new bearing in the freezer for about an hour before you install it, to ease installation.

1. Remove bolt (8mm) to drain oil from rear differential. Check O-ring for damage.

2. Remove rear tires (17mm) and shocks (13mm and 17mm upper bolts, 10mm lower bolts)

3. Remove brake calipers (10mm) from right rear knuckle and secure them to the frame/ A-arms

4. Remove 4 bolts (13mm and 17mm) that connect the rear knuckles to the rear A-arms.

5. Turn the knuckles 90 degrees using them as a handle, push inward towards the rear diff and quickly pull back to remove the axles from the diff. May have to do this several times to get the axles to release.

6. Take off the seat and the airbox cover.

7. Slide the crank case vent tube clamp back and disconnect the tube from the airbox.

8. Remove the 4 philips head screws that secure the airbox to the frame

9. Loosen the clamp (1/4” or flathead screwdriver) on the intake boot and remove the airbox.

10. Remove the 4 bolts (10mm) from the output flange on the drive shaft.

11. Remove 3 torx head bolts (T40) from the pinion housing.

12. Remove 2 bolts (13mm and 17mm) that hold the diff to the frame.

13. Pull back on the drive shaft to separate the 2 halves of the output flange.

14. Rotate the pinion housing up towards the airbox opening and remove through the opening, careful not to damage the gasket if you don’t have a replacement.

Optional steps for replacing rear drive shaft boot:

a. Remove the bands off of rear drive shaft boot and remove boot from output flange and diff input shaft. Bands may be reusable.
b. Clean and regrease drive shaft as needed.
c. Reassemble drive shaft and install bands after housing is rebuilt.

15. Once the pinion housing is out, remove the snap ring that holds the input shaft in the housing and remove the input shaft.

16. Remove the pinion seal using a seal puller or screwdriver, taking care not to scratch the housing.

17. Remove the snap ring that holds the pinion bearing in the housing and remove the bearing.

18. Reassemble in reverse order.

19. Fill rear differential with 8.5oz of gear oil


40,676 Posts
Thank you cr it's write ups like these that make this site so awesome !!!! I pinned this
1 - 3 of 3 Posts