Differential service

Traxxas X-Maxx Ultimate, 77097-4; original equipment covered by the cited edition.

Start with the correct reference

The manual describes front and rear differential access and oil servicing. Match the axle and original assembly; this is not a center-drive service reference.

Differential access and servicing, PDF p. 29 (opens in a new tab)
Manufacturer procedure · 77097-4-OM-EN-R05.pdf

Service guides

Choose the operation for the assembly being serviced. Each step links to its manufacturer reference.

X-Maxx Ultimate front and rear differential removal and refill

Traxxas X-Maxx Ultimate (77097-4); original front or rear differential, excluding the center drive. Match the front or rear removal illustration on physical PDF page29.

Before starting

Use only silicone differential oil. This manual lists SAE 10,000W as the factory front fill and 30,000W as the rear fill.Source, PDF p. 29 (opens in a new tab)

Steps

Remove the two 4 x 20mm button-head cap screws securing the bumper to the skid plate. Rotate the corresponding bumper up and out of the way.Source, PDF p. 29 (opens in a new tab)
Remove the one 4 x 12mm button-head cap screw and four 4 x 16mm button-head cap screws securing the differential cover. Reach the bottom screws through the slots in the skid-plate lip.Source, PDF p. 29 (opens in a new tab)
Remove the differential cover, then lift the differential out of its housing. The drive axles slide out of the differential cups.Source, PDF p. 29 (opens in a new tab)
Over a towel, remove the four 3 x 15mm cap screws and separate the differential case from the ring gear.Source, PDF p. 29 (opens in a new tab)
Drain the fluid. Remove the spider gears if needed to make draining easier.Source, PDF p. 29 (opens in a new tab)
Reinstall any removed spider gears, then fill the case until the spider gears are submerged halfway.Source, PDF p. 29 (opens in a new tab)
Align the screw holes and rejoin the ring gear to the differential case. Keep the rubber gasket in place to prevent leakage.Source, PDF p. 29 (opens in a new tab)
Install the four 3 x 15mm cap screws and tighten securely.Source, PDF p. 29 (opens in a new tab)
Reinstall the differential by reversing the documented removal sequence.Source, PDF p. 29 (opens in a new tab)

Parts, tools and consumables

Required by the instructions

Keep the differential rubber gasket seated when closing the caseprerequisite
Check the seal before refitting the case screws. The manual does not mandate replacing it at every service.
Requirement source, PDF p. 29 (opens in a new tab)

Listed in the reference

Silicone differential oil for front/rear serviceconsumable
Use the axle-specific setting or tuning choice for the original assembly; this is not the center-drive fluid.
Requirement source, PDF p. 29 (opens in a new tab)

Part links open an exact-model OEM listing. Quantities, reused hardware and condition-dependent replacements may need checking in the manual. A listed part is not an instruction to replace it.

Setup specifications

Differentials: Limited-slip front and rearStock
Sources
Source 1: traxxas.com (opens in a new tab)
Diff oil, front: SAE 10,000W (maker grade)Stock
Sources
Source 1: traxxas.com (opens in a new tab)
Diff oil, rear: 30,000W (maker grade)Stock
Sources
Source 1: traxxas.com (opens in a new tab)

Keep the axle positions and original units shown. Values describe the cited configuration. Replacement-derived and community figures keep their stated basis.