TRAXXAS RALLY • 25
viscosity silicone oil. The rear differential is filled with grease, but can
also be tuned with silicone differential oil.
Only use silicone oil in the differentials. Traxxas offers SAE 10,000W,
30,000W, and 50,000W viscosity oil (see your parts list). The
differentials have to be removed from the vehicle and disassembled
to change/replace oil.
Follow the steps on the following page to access and refill the front
and rear differentials.
Front differential:
1. Remove the two 3x15mm button-head screws that secure the
upper bumper/body mount to the differential (diff) case.
2. Turn the chassis over and remove the three 4x10mm
countersunk screws that hold bumper/skid plate to the
bulkhead. The two rear screws do not need to be removed.
3. Slide bumper/body mount assembly off of the chassis.
4. Remove 3x15mm button-head screw from diff tie bar.
5. Slide tie bar off of the vehicle.
6. Remove two 3x15mm button-head screws from diff cover.
Do not remove the two screws that secure the shock tower.
7. Use a 1.5mm hex wrench to remove the two screw pins that
hold the driveshaft yokes to the differential output shafts.
Remove the differential cover and slide the differential out of the
front of the case.
8. To reinstall the differential, reverse the steps.
Rear differential:
1. Remove the two 3x20mm button-head screws that secure the
top bumper mount to diff case.
2. Turn the chassis over and remove the two 3x12mm countersunk
screws that hold the bumper/skid plate to the bulkhead.
3. Remove the 3x20mm button-head screw from the bumper
mount and tie bar.
4. Slide bumper assembly off of the chassis.
5. Remove the tie bar from the chassis.
6. Remove the two 3x15mm button-head screws from differential
cover. Do not remove the two screws that secure the shock tower.
7. Remove the differential cover and slide the differential out of the
front of the case.
8. To reinstall the differential, reverse the steps.
Refilling the differential:
1. Remove the four 2.5x10mm screws from the differential case
and carefully pull the diff case halves apart. Work over a towel to
collect any fluid that drips from the differential.
2. Drain the fluid from the differential. You may wish to remove the
spider gears from the differential to make this easier.
3. Place the spider gears back into the diff case, if you removed
them. Fill the diff case with fluid until it the spider gears are
submerged half way.
4. Rejoin the diff case halves, using care to align the screw holes.
Be sure the rubber gasket is in place, or the differential may leak.
5. Install the 2.5x10mm screws and tighten securely.
ADVANCED TUNING ADJUSTMENTS
1.
3x15 BCS
1.
3x20 BCS
4.
3x15 BCS
4.
6.
3x15 BCS
6.
3x15 BCS
2.
4x10 BCS
2.
3x12 BCS
3.
3.
3x20 BCS
Front Differential Removal
Rear Differential Removal
5.
5.
