129 0406 10z+ford F150. Transfer Case Oil Pump - Photo 9540274

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Insufficient lubrication can mean a quick and expensive end to your transfer case, so Heady highly recommends a new oil pump and filter. He notes that it's important to make sure that the hose connections are tight and the unit is installed properly.

129 0406 01z+ford f150+right front view

Motive Gear knew exactly what we'd need to rebuild our BorgWarner 1356 transfer case, and they sent us a variety of new parts, including an input shaft/carrier assembly, a high/low shift hub, an oil-pump assembly, a four-wheel-drive shift fork and a bearing-and-seal kit.

129 0406 15z+ford f150. transfer case temperature gauge

To remove a manual-shift transfer case, begin by removing the driveshafts. Drain the fluid, disconnect the shift linkage, vent hose and the 4WD indicator-switch wire. Then you can remove the six bolts connecting the transfer case to the transmission. Some of these bolts are difficult to access and may require removing the exhaust pipe or using a swivel socket to make the job easier.

With the six mounting bolts removed, the transfer case can simply be slid off the transmission output shaft. With the transfer case out of the truck, Heady completely disassembled the transfer case on the bench and cleaned all of the original components in a high-temp parts washer.

With the transfer case apart, we could see how the internal components were wearing. Inside the transfer case are two shift forks. Both have wear pads, and these pads need to be inspected closely. If they're worn, the transfer case can be hard to engage in four-wheel drive and/or 4-low, and/or they can cause the unit to pop out of gear during use. If they're worn, the shift forks are replaced with new units. Ours were in good shape, but we replaced the four-wheel-drive fork with the new unit anyway.

129 0406 07z+ford f150. transfer case planetary unit

129 0406 08z+ford f150. transfer case planetary units

Over time, the transfer-case chain will stretch. Sometimes, chains will stretch so much that they can actually slap the inside of the transfer-case housing. Because of this, it's important to check for excess slop in the chain. Ours was in great condition, so we reused it.

Insufficient lubrication can mean a quick and expensive end to your transfer case, so Heady highly recommends a new oil pump and filter. He notes that it's important to make sure that the hose connections are tight and the unit is installed properly.

Grit can get between internal surfaces like the output shaft and the drive sprocket. Here, Heady inspects the inside of the drive sprocket right after he removed it from the case. He says that most of the time, the output shaft will take the brunt of the damage from foreign matter. Both of ours were in good shape, so we cleaned them up and reused them.

It's always a good idea to replace all bearings and seals. Most rebuild kits come with all of the required components to complete a rebuild.

Reinstallation of the transfer case begins by placing the new gasket on the transmission. Make sure you clock the gasket so that it is lined up with the six mounting boltholes.

Lift the transfer case into position and slide it onto the transmission output shaft until it mates with the transmission housing. Install and tighten the six mounting bolts, reconnect the shift linkage, vent hose, 4WD indicator switch wire and driveshafts. Finally, fill the unit with ATF fluid and check for proper operation.