Chevy/GMC Duramax 01-04 LB7 Discussion of Chevy and GMC Trucks with LB7 Duramax Turbo Diesel Engines

T-Case not pumping after new pump

Old 07-08-2019, 05:59 PM
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Join Date: Sep 2014
Location: Charleston, SC
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Default T-Case not pumping after new pump

NP205XHD trying to help a friend fix his NP205XHD T-Case he has a 2002 GMC Duramax.
Sorry in advance for writing a story but I wanted to describe exactly whatís happening. Any help would be greatly Appreciated.
Hereís what happened... he was driving and the Output shaft seal blow out of the case.
So we tore the case down and got the upgraded case half, new pump, new chain. We cleaned the screen/filter and the pump tube. Then we put it all back together and install it. It went about 10 miles and blow the output seal again, destroyed the rear case bushing, and the marred up the slip Yoke. So we pulled it again tore it down and discovered my buddy didnít put the o ring on the tube. So we obviously figure that was the cause. So he bought another rear case half and installed an o Ring on the pump tube. Then we inspected everything again and put it back together. This time we cautiously left the yoke and driveshafts off to verify oil was going to the rear bushing. So at idle the Output shaft Bushing remained bone dry and does not show fluid until 3000rpms in 2nd Gear. Is that normal. The oil only shows up on the bottom of the bushing and not the top so I donít know if it just splashing fluid from the chain or if itís from the pump.

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