Pump rub

[BirchyBoy]

I did a search but couldn't find anything with those words. I came across this in another forum today. Does anyone know about this issue with the 246 transfer case? There are several companies that make upgrade parts, but not sure about it. Here's the text from one of the websites:

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.

http://www.merchant-automotive.com/p-4017-transfer-case-pump-upgrade-kit.aspx

 

[SunlitComet]

Yes it is an issue after many miles on it. It can create a fluid leak right thru the case if it gets real bad and could fry your t-case if it has no lubrication. If you t-case is being torn down for some reason look for the damage and address as needed.

 

[BirchyBoy]

Is it easy to spot underneath the truck? Mine's at 167k and I'd like to know if it's OK.

 

[BRUTUS_T_HOG]

You will see an oily mess on the passenger side of the case and a pinhole.

 

[BirchyBoy]

Thanks!

 

[Duramax05blk]

At 180k I had a pin hole on my duramax tcase installed a merchant kit dap of jb weld 20k no issues


Sent from my iPhone using Tapatalk. Excuse my grammar the iPhone makes me iStupid!

 

[99Vortec]

The Merchant Automotive site also has a nice .pdf on installation instruction.

http://www.merchant-automotive.com/tech/tcpv2.pdf


I am also wondering if the pump upgrade kit is not necessary if using one of the shell's from http://www.transfercases.com/replacement.case.shell.htm

(TYVM for the transfercases link Sunlit.)

"Our special replacement shell half for the rear of these transfer cases fixes that issue. They are made of heavy grade aluminum, not thin magnesium. In addition, these replacement upgrades correct a snap ring groove problem and require no adapter plate. You will appreciate the durability and craftsmanship built into these parts."

I have to upgrade mine soon.

 

[Tom Joad]

So do i.