GM Pump Rub in Transfer Case
GM transfer cases 261 and 263 are prone to a condition known as Pump Rub. It is where the pump used to circulate the fluid in the transfer case wiggles back and forth wearing a hole in the transfer c...
Forum Discussion
There TWO potential issues with these NP transfer cases...
One is that the snap ring for the tail housing shaft doesn't hole it well enough
and allows the shaft to move rearwards. A clamp on collar is that fix. I've seen
kits with new snap ring, but the collar is the best, IMHO
Other is this topic and is with the impeller/pump on the shaft. The first NP's
relied on the chain to drag lube 'up there' and a must was to run in 4x4 every
once a while...like once a month
This pump problem has two types of fix-it-kits. One is a metal plate to increase
the Xfr-Case wall thickness. Those kits are in the under $10 buck range. The
better fix is with a ADDITIONAL disc in the pump/impeller stack and comes with
a stack of gaskets too
Many DIY'ers just epoxy the hole and seems to a be holding from the years I've
read about that one
One is that the snap ring for the tail housing shaft doesn't hole it well enough
and allows the shaft to move rearwards. A clamp on collar is that fix. I've seen
kits with new snap ring, but the collar is the best, IMHO
Other is this topic and is with the impeller/pump on the shaft. The first NP's
relied on the chain to drag lube 'up there' and a must was to run in 4x4 every
once a while...like once a month
This pump problem has two types of fix-it-kits. One is a metal plate to increase
the Xfr-Case wall thickness. Those kits are in the under $10 buck range. The
better fix is with a ADDITIONAL disc in the pump/impeller stack and comes with
a stack of gaskets too
Many DIY'ers just epoxy the hole and seems to a be holding from the years I've
read about that one
