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.
1500, 1500HD, 2500, 2500HD, 3500
NP246, NP261HD, NP263HD, NP261XHD, NP263XHD
NP246, NP149
1500, 2500
NP246, NP261, NP263, NP263HD
1500, 2500

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.
 Average Rating:  5 Star Rating
 based on 10 Customer Reviews  
Write A Review
   Great product all around, October 27, 2017  By Anonymous (Gray, ME)(Verified)
Just did my 263 @ 150k. Thankfully it was still in great shape. Great product, and instructions. Very easy. Only thing i'd add to the instructions is to clean the magnet below the oil pickup before reassembly.
   Complete kit, October 19, 2017  By Daniel (Conway, AR)(Verified)
Great product and easy to install. I love that it comes with everything you need to complete the job.
   Rub Kit, September 20, 2017  By James (BALSAM LAKE, WI)(Verified)
Product is everything as advertised,came in a timely fashion, only thing I would add to the directions is to lube the pump plates before you reinstall with grease or transmission fluid.
   pump rub, September 7, 2017  By Anonymous (PAYSON, AZ)(Verified)
Quality product and easy to follow instructions.
   Transfer Case Pump Upgrade, August 22, 2017  By Anonymous (Littleton, CO)(Verified)
This is a great product design to save your case if you catch it in time., I did...98k miles
The online video walks you right thru it step by step great job Merchant Automotive!!!!!
   2006 K3500, August 22, 2017  By Anonymous (Shoreview, MN)(Verified)
Fits perfect. Easy install. 263XHDGM
   Pump upgrade, August 22, 2017  By Anonymous (FAYETTEVILLE, NC)(Verified)
Great part easy to install. Easy on the wallet
   Great product, August 21, 2017  By Nick (Byron, IL)(Verified)
Heard from a friend about this fix. Easy do it yourself update. Instructions are step by step, can't mess it up. Glad I did this before I had any problems with my transfer case. Also great that Merchant Automotive does offer bearing and seal kits.
   Great Product, August 3, 2017  By Anonymous (Welland)(Verified)
The parts and the video on how to install them were great i have put about 4000 km on since i installed the new pump. the machining and fit of all the parts were great thanks for all the help and the follow up to make sure every thing went well thanks again and i have recommended you to a lot of friends who have a lot of duramax trucks and chevy gas trucks thanks again
   Awesome! Thank you Merchant, July 26, 2017  By John (New York, NY)
I do not understand why GM did not do a recall on this issue. Thank you so much for making this product. I did not want a hole in my T-Case!
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