The Merchant Automotive Deluxe Seal kit for the NP263XHD includes all the seals used throughout the transfer case to complete the proper reassembly after a transfer case rebuild or major overhaul.

KIT Includes:

• A23 Speed Sensor Seal
• A13 Rear Output Seal
• Transfer Case Gasket
• Snap Ring Hole Grommet
• A7 Front Transfer Case Output Seal
• A9 Front Transfer Case Input Seal
• Selector Shaft Sensor, Detent Plug O-Ring
• B30 XHD HD Transfer Case Pickup Tube Seal, 49-Spline Pump

What is a Transfer Case Pump Rub Failure?

GM transfer cases used from 1998 through early 2007 use a gear pump inside the case that is driven off the mainshaft. The pump forces oil to the planetary as well as the drive sprocket sleeve. Because the pump is driven by the shaft, the housing of the pump must float in the rear housing.

There are tabs around the pump housing that fit into spots in the rear housing to locate the pump housing and prevent it from spinning inside the case with the mainshaft. Over time, the pump tabs can start to wear on the rear housing. GM installed a spring steel clip in the housing intended to prevent wear, but the clip can break and be rendered useless.

Since the pump housing is aluminum and is a harder material then the magnesium rear housing, it can wear a hole in the rear housing and cause a very small leak. This leak is frequently high enough on the case that it typically will not leak when vehicle is not moving and therefore not leaving any drops on the ground; it will however leak while the vehicle is in motion. Unfortunately since the transfer case does not have a low fluid indicator the pump rub failure is often not found until there is transfer case damage from running the case out of fluid.

Avoid costly repairs to your transfer case by preventing Pump Rub by installing a Merchant Automotive Transfer Case Pump Upgrade kit in your transfer case today, before it happens to your vehicle.

With installation of this kit, you will have a Limited Lifetime Warranty against pump rub. If your case ever wears a hole in the new rear housing with the upgrade installed. We will buy you a new transfer case.

However, if you already have a hole in your case, we recommend installing a new rear housing for a complete repair. The MA Lifetime Warranty will only apply to installations with a new rear housing.

FAQ:

Is the transfer case behind the Allison 1000 or ZF6 transmission in a 2001 through early-2007 truck an NP216XHD or NP263XHD?

The easiest way to know the difference between transfer cases installed in 2001 through early 2007 GM HD trucks is the shift selector mechanism. Both Chevrolet and GMC trucks using the NP261XHD transfer cases use manual shift selection with a floor mounted range selector. Truck with electronic (push button or knob on the dash) shift selection are equipped with the NP263XHD transfer case.

How tight do I tighten the transfer case mounting nuts for the NP261XHD or NP263XHD at the transmission output adapter?

The factory recommended torque specification is 37 ft-lbs for the transfer case adapter nuts for both the NP261XHD and NP263XHD.

How tight do I tighten the transfer case assembly bolts at the transmission output adapter?

The factory recommended torque specification is 27 ft-lbs for the transfer case assembly bolts for both the NP261XHD and NP263XHD.

I hear a grinding noise at low speed after reassembling my transfer case. What could that be?

A low speed grinding noise is most commonly caused by the rear output bearing snap ring not being fully seated causing the bearing to move out of proper alignment. Verify that the snap ring is fully engaged and properly seated in the rear housing and the locating groove in the bearing.

What would cause a speed sensor correlation code after installing this upgrade?

A speed sensor correlation code is often accompanied by a low speed grinding noise and is frequently caused by the rear output bearing snap ring not being fully seated causing the bearing to move out of proper alignment. Verify that the snap ring it fully engaged and properly seated in the rear housing and the locating groove in the bearing.

Year

Vehicle

Chassis

Transfer Case Model Number

2001-2007

Silverado/Sierra

2500, 2500HD, 3500

NP263XHD

Details:

• Engine Manufacturer: Duramax
• Liter: 6.6 Liter
• Engine Designation: LB7, LLY, LBZ
• Engine Years: 2001-2007
• Transfer Case Model: 263XHD

Applications:

• 2001-2007 Silverado/Sierra 2500HD/3500HD LB7/LLY/LBZ