Transfer Case Pump Upgrade Kit

The Ultimate Solution to a problem found in Chevy and GMC light duty trucks and utilities from 1998-2007
The Ultimate Solution to a problem found in Chevy and GMC light duty trucks and utilities from 1998-2007
Price Range:   $75.00 - $113.94
Pump Upgrade Kit: 
Add Magnetic Drain Plugs? ($12.95): 
Add Transfer Case Fluid?($24.99): 
Select Options
To open instructions click here.

Here is the best upgrade you can make to your GM transfer case(model 136, 146, 246, 261, 261HD, 263HD, 263XHD, 261XHD). Prevent the ever increasing problem of pump rub.

What is "pump rub"
The GM transfer cases 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 5 tabs around the housing that fit into spots in the rear housing to position the pump. Over time, the pump 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 render useless

Being that 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 high enough in the case that it typically will not leak when vehicle is not moving and therefor not leaving any drops on the ground. Typically the condition is not found until there is transfer case damage from running the case out of fluid.

Avoid costly repairs to your transfer case by preventing this condition.
Full installation instructions are available right here on this site. Look under the Tech Information link on the home page for step by step directions.
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.
Included in the kit:

  • Merchant Automotive billet transfer case pump housing
  • Transfer case adapter gasket at trans
  • RTV Silicone
  • Blue Threadlock
If you already have a hole in your case, its recommended to install a new rear housing for a proper repair. Lifetime warranty will only apply to installations with a new rear housing.
Check out our transfer case upgrade as featured on Truck U TV on Speed Channel
Application table.
YEAR
TRUCK
WEIGHT
MODEL NUMBER
1998-2007
SILVERADO / SIERRA
1500, 1500HD, 2500, 2500HD, 3500
NP246, NP261HD, NP263HD, NP261XHD, NP263XHD
1998-2003
BLAZER/JIMMY
-
NP236
1999-2005
ASTRO/SAFARI
-
NP136
1999-2007
ESCALADE
-
NP246, NP149
2002-2007
AVALANCHE
1500, 2500
NP246, NP261, NP263, NP263HD
1998-2007
SUBURBAN/YUKON XL
TAHOE/YUKON
1500, 2500
NP246

FAQ - Transfer Case Pump Upgrade Kit

What do I do with the OEM anti rattle clip when installing this upgrade?
You can discard the factory clip during installation of this kit. Its been designed to work with the clip removed.

What other parts will I need to install this upgrade kit?
We tried to make the kit all inclusive for a basic installation. This is taking into consideration of course that its being installed as preventative measures. If its being installed as part of a repair or after pump rub has occured, there is no real way to know the extent of the damage inside the case until it is torn down. Most times, as long as the case has not run out of fluid, it can usually be repaired with a new rear housing and seal and prevented from ever happening again using the upgrade kit. Regardless of the reason for installing this upgrade, you will need to refill the transfer case with oil. We recommend our Performance Transfer Case Oil for use in ALL transfer cases.
Replace your stock drain plug with Magnetic Drain Plugs to catch small debris and help extend fluid life. Kit contains a Magnetic Drain plug and a new fill plug made out of a high strength corrosion resistant 304 Stainless Steel.
  • Promotes transfer case performance
  • Increases shifting performance
  • Dramatically reduces wear
  • Increases component efficiency
  • Blended specifically for use in GM transfer cases
  • May be used in GM, Ford and Chrysler transfer cases
  • For use in diesel or gas transfercase
  • Cost effective upgrade for Auto Track II
  • Performs in manual or electric shift applications
  • Reduces irritating drive shaft clunk
  • Increases drive line performance by reducing clutch chatter
  • Drastically reduces wear on internal components & seals
2 Quarts (64 fluid oz.) One Transfer Case will use 64 fluid oz.
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