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  • Transfer Case Pump Upgrade Kit | 1998-2007

Transfer Case Pump Upgrade Kit | 1998-2007

31 Reviews
SKU: 10001


Here is the best upgrade you can make to your GM transfer case by preventing the ever increasing problem of pump rub.

Included in the kit: 
  • Merchant Automotive Billet Transfer Case Pump Housing
  • Transfer Case Adapter Gasket
  • RTV Silicone
  • Blue Threadlock

    To open instructions click here.

    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 be rendered 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. 

    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.

    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.


    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. It's 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 it's being installed as part of a repair or after pump rub has occurred, 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.


    1500, 1500HD, 2500, 2500HD, 3500 
    NP246, NP261HD, NP263HD, NP261XHD, NP263XHD 



    NP246, NP149 
    1500, 2500 
    NP246, NP261, NP263, NP263HD 

    1500, 2500 

    2500HD 3500 Silverado Sierra 6.6L V8 Duramax diesel engines:
    LB7, LLY, LBZ

     1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007 early *

    NOTE - This upgrade kit MAY NOT BE COMPATIBLE with some aftermarket aluminum rear transfer case halves due to the inconsistent manufacturing tolerances seen in them. Be sure to verify correct fitment prior to installation

    Ratings & Reviews

    31 Reviews

    • 3 stars
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    • 1 star
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    Transfer case upgrade kit

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    Love this kit. Third install. Great product.

    Great Instructions

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    The product seems as advertised. Huge balue in the written and pictured instructions. I have seen too many long cumbersome clunky ambiguous YouTube vids - so really appreciate these.

    For my tcase 2006 model 246GM with 2.72 ratio I needed to begin to separate the case halves about three quarter inch and then open C-clip and move the shaft forward more concurrently and less in a sequence as apparent in the instructions.

    Not a product issue, but the C-clip does not have rings in the end to clasp with typical tool and couldn’t find a specialty tool on long weekend after 4 stores...so, used regular tool with improvised ends via 2 small aluminum ‘crush type’ cable clamps to convert tool. Annoying, frustrating, time consuming - so depending on your toolbox, be prepared to chase down a decent tool.

    Transfer case parts and pump upgrade

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    You all are the best, ypu all are the real deal. I will always return to you. Learned my lesson from one of you competitor.

    Nice Kit

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    Really nice kit. Should keep my new case half from getting rubbed through like the original did. Installation was straightforward and the instructions were clear. All around a good product.


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    Very good part. Will reccomend. Fixed my issue!

    Second to none

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    Great product in a nice bundle with everything you need. Awesome video and instructions. Highly recommend if you have one of the affected transfer cases.

    Great service

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    Part fit perfectly and they have a great video online showing installation instructions.

    Great parts fast shipping

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    Fit perfect. Great directions.

    PUMP Rub Upgrade kit

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    The Pump Replacement Part worked great and the Oil Was amazing. However, the Gasket for the T case did not fit the Bolt Hole Pattern.

    Pump upgrade

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    Overall Video was very good.
    Some feedback. Replace the oring every time you remove the tube. Squirt some oil into the hole of the pump as a prelube before final install. Clean and inspect suction screen for damages replace if needed.
    Leave the factory supplied magnet in place it's surface is much larger then your drain plugs also grabs magnetic debris before entering the pump.
    Compliment the system by using you magnetic plugs as added control of magnetic debris.
    Supply new pump screws and a torque spec as there easily stripped not all transfer cases use Torx some use Phillip's head screws.
    Apply thread locker on case half bolts as well and don't discard the cup type washers there used as a corrosion preventer.
    Show damaged cases in the video so people understand what happens. Also show bad bearings verse new bearings, promote the use of new parts like seals and gaskets.
    Also some transfer cases use a wave washer against the pump you want to show correct location if used.

    Great products you have keep you the great work !

    Canadian customer

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    Recieved this kit very quickly, I believe 3 business days. Over all its exactly as described. Great product and I appreciate MA's outstanding quality. One thing that bothered me was the additional 46 dollar brokerage fee upon delivery to my location. My fault for not being informed however, as I didn't look at their shipping details before making my purchase and it clearly states that there may be additional fees on international orders. If your a canadian buyer perhaps you might look into purchasing their product from an outside source with different shipping method to avoid these fees. Other than the additional cost I'm very pleased with both the product and speedy service of merchant automotive.

    Just do it!!

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    Had 235k on the truck when I did my build. The transfer case was all original, no leaks but I bought the kit and transfer case half over the objection of the shop. When they got into it, the pump had rubbed nearly completely through. Glad I forced the issue.


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    Was impressed with quality of productthe transmission shop I had installed showed me what they use-thin piece stamped-not near the quality. They were also impressed with quality annd fitment. Install was straight forward with no complications-good directions.

    The dreaded "PUMP RUB" got me

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    I installed this in my Chevy 2500 HD too late to save the case, and tried using a different vendor for the case half. Unfortunately, the case half had a different size driveshaft output size and I had to do it twice, after buying the correct case from Merchant Auto. Don't do what I did, buy from Merchant and save the labor.

    Pump upgrade

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    Really nice product, quick shipping and quick help finding the right part.

    Best Pump rub kit out

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    Got this quality kit 7 years ago. I've installed several since. This by far is the best kit on the market. Still in my truck to this day.

    Quality Product,

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    Quality Product, Product exceeds expectations. Simple to install with basic mechanical experience.

    Potential problems solved!!!!

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    We got lucky as our 2006 LBZ only has 75,000 on it, and the spring clip was it place BUT, it had already started to wear a small spot. We installed the kit and
    also installed the transfer case brace. Instruction were clear and easy to follow. We also put in new seals, one was a real turd, but we replaced them all, which
    took a little longer that just the kit. The brace only took a few minutes when putting case back in. The mechanic that gave me a hand is a transmission 'guru'
    and was impressed with both the hub kit and the brace. He thought they were excellent preventative measures and has seen several cases destroyed by the problems these two items prevent. Am very satisfied with these two products. The rear output bearing was in great shape so we did not need to use it,

    Transfer case pump rub kit

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    Excellent product !!!!

    I am an OG pump housing buyer

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    This kit is nothing but fantastic, I bought my kit back in 2006 when they were just coming out, and the price was 275 bucks! Still money well spent. Well here I am 12 years later and still running the same case half with my epoxy patch and all is well! If you have not bought this kit, I can show you pictures of what I have encountered inside transfer cases.... do the pump housing, you will not regret it!

    Great product all around

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    Just did my 263 at 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.


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    You earned a customer for life! Kit was complete and as easy to install as they said it would be! So nice to find a company that delivers on its claims!

    Complete kit

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    Great product and easy to install. I love that it comes with everything you need to complete the job.

    pump rub

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    Quality product and easy to follow instructions.

    Transfer Case Pump Upgrade

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    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!!!!!