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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.
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
- Merchant Automotive sticker
|1998-2007||SILVERADO / SIERRA||1500, 1500HD, 2500, 2500HD, 3500||NP246, NP261HD, NP263HD, NP261XHD, NP263XHD|
|2002-2007||AVALANCHE||1500, 2500||NP246, NP261, NP263, NP263HD|
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.