Place the Countershaft Assembly vertical on a clean flat surface. If the countershaft bearings were removed, use the proper bearing driver and maul to reinstall the Countershaft Bearings.

Mark each Countershaft for correct timing. On each countershaft there is a “0” stamped on the countershaft. Mark the corresponding tooth with a highly visible paint pen. Also mark the Splitter Gear mating gears on each countershaft.

Place Countershafts in the fixture or on a flat surface. Turn the Countershafts until the two teeth marked on each shaft are towards the middle.

Align the Auxiliary Mainshaft Assembly so the timing marks on the Reduction Gear match up with the timing marks on the 2 Auxiliary Countershafts. Also, align the timing marks on the splitter gear to match time.

Install Range Yoke into the Synchronizer Sliding Slot.

Note: Ensure the Range Yoke offset side is facing down.

Lay the Auxiliary Case Housing front on a clean flat surface. Install the Bearing Race in the Bearing Bore.

Place the Auxiliary Housing over the Countershaft Assemblies and the Auxiliary Mainshaft Assembly.

Ensure the rear Auxiliary Mainshaft bearing spacer is installed on the shaft.

Heat the Rear Auxiliary Mainshaft Bearing cone and install the bearing, tapered side down, on the shaft.

Position a new gasket on the Rear Bearing Cover, and install the cover.

Apply Eaton Sealant #71205 or equivalent to the retaining cap screws, and install the six (6) cap screws in the non-chamfered holes. Torque to 35-45 lb-ft (47.45-61.01N•m).

Install the Auxiliary Countershaft Bearing Races.

Install each Auxiliary Countershaft Retaining Strap with 2- 3/8” NC x 1” NC and 1 3/8” NC x 2-1/2” clean cap screws.

Note: Do not use an air gun on strap bolts. Tighten by hand until cap screws are snug

To assist in the installation of the Range Cylinder, place the Auxiliary section in a vice.

Position a new gasket on the range Cylinder Mounting Surface of the Auxiliary Case.

Install the Range Cylinder through the Range Cylinder Bore on the Auxiliary Case housing. Position the Range Yoke Fork inside the open section of the cylinder.

Install Range Yoke Bar from the rear of the Auxiliary case.

Note: Ensure that the Yoke Bar passes through the eye of the Yoke fork.

Align the 2 groves on the Yoke Bar and install the 2 retaining bolts through the bores on the Range Yoke Fork.

Install new O-rings on the ID and OD of the piston, then lubricate with silicone.

Install Piston into the bore of the Range Cylinder Install with the flat side of the piston facing rearward.

Secure the piston with the retaining nut, torque to 70-85 lb-ft (94.91-115.24 N•m).

With the Auxiliary Section still in the vice. Position the Splitter Sliding Clutch on the Splitter Yoke fork and bar. Engage into the Splitter Gear to maintain its position

Install small O-ring in the Cylinder Housing Bore if previously removed

Position a new gasket between the Splitter Cylinder and the Auxiliary Case Housing bore. Install the Splitter Cylinder.

Install new O-rings on the ID and OD of the piston. Lubricate with silicone.

Install new O-ring on the end of the yoke bar inside of the cylinder housing.

Install the piston into the Splitter Cylinder with the recessed side facing the rear of the transmission.

Secure piston with the 3/4 lock nut. Torque to 30-36 lb-ft (41-49N•m).

Attach the Auxiliary Section lifting bracket to the top of the Auxiliary Case.

Position a new Auxiliary Case Gasket on the mounting surface of the Main Case.

Install the Auxiliary Case Assembly onto the transmission Main Case dowel pins. Using the Output Shaft, wiggle the auxiliary case forward until it is as far forward as possible. Remove the auxiliary section lifting bracket.

Apply Eaton Sealant #71205 or equivalent to the 19 retaining cap screws. Secure the Auxiliary Section to the main case. Torque to 35-45 lb-ft

Remove the Auxiliary Countershaft support straps and install a 0.100” shim between the cover and Auxiliary Countershaft. Use two of the counter shaft bearing cover bolts and torque bolts to 7 lb-in. Spin the Output Shaft multiple times to assist in seating the bearing races. Ensure cap screws are still torqued at 7 lb-in.

Using feeler gages, measure the gap between the Auxiliary Countershaft covers and the Auxiliary Case. Use multiple positions closest to the cap screws.

Subtract the thickness of feeler gauges needed to fit in between the auxiliary case and auxiliary counter shaft covers from 0.100". Use that number to pick a shim that will allow for end-play of within 0.001"–0.005".

Note: Example: 0.042" of feeler gauges fit in between auxiliary case and the auxiliary Counter Shaft bearing cover. Subtract 0.042" from 0.100" which equals 0.058". A shim of 0.052"–0.055" would be required for the 0.003"–0.005" end-play. (If the required thickness shim does not exist, use the closest undersized shim.)

Install required shim into bearing bore. Install new Auxiliary Countershaft gaskets and install Auxiliary Countershaft Covers.

Position new gasket on the Range Cylinder Cover mounting surface.

Install Range Cylinder Cover. Torque cap screws to 30-35 lb-ft.

Position new gasket on the Splitter Cylinder Cover mounting surface.

Install Splitter Cylinder Cover. Torque cap screws to 30-35 lb-ft.

Install the Output Yoke. Ensure yoke is properly seated against Output Shaft.

Secure the Output Yoke with the 2 retaining bolts. Torque to 84–92 lb-ft (113–124 N•m).