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Changing shift shaft seals...

Posted: Sat Nov 21, 2009 10:50 am
by refit1701
I've read back and found the post on the shift shaft seal replacement. Even though nothing is leaking on my transfer case I have decided to go with all new National seals on it. I have a pile of seals and redi-sleeves here on the desk.

I'm going to guess that you just take the linkage off and remove the seals from around the shafts as best you can, then clean and replace? My shafts are in very good condition after I cleaned them so hopefully I won't have any leakage AFTER I put new seals on.

Re: Changing shift shaft seals...

Posted: Sat Nov 21, 2009 1:30 pm
by MSeriesRebuild
refit1701 wrote:I've read back and found the post on the shift shaft seal replacement. Even though nothing is leaking on my transfer case I have decided to go with all new National seals on it. I have a pile of seals and redi-sleeves here on the desk.

I'm going to guess that you just take the linkage off and remove the seals from around the shafts as best you can, then clean and replace? My shafts are in very good condition after I cleaned them so hopefully I won't have any leakage AFTER I put new seals on.
Give this some thought, if the seals are not causing a problem, it actually is not a good idea to change them. The reason is this; as a general rule, the shift shaft seals are not easy to remove with the shafts in place. Most of the time they tear into small pieces and are tough access unless the shafts are removed. This makes the likelyhood of scratching or scoring the seal mating surface on the shafts or the seal bore in the case very high. If this happens, you will have a leaking issue that a new seal will not fix. Your best bet is to leave well enough alone if no leaks exist; wait until the case is disassembled or until leaks demand service. At this time it's better to pull the case down for a cleaning, inspection, and repair / adjustment as necessary going back with all new seals and gaskets. You might get by, like I said, the likelyhood is very high that problems will be encountered.

Posted: Sat Nov 21, 2009 2:50 pm
by refit1701
Sounds like a plan. The idea of not changing the shift seals had crossed my mind since they look in very good shape from the outside and the shafts are nice and smooth.

I think I will change the others though, since they do all the turning. I'll inspect them first though. I'm afraid when I get the truck back together and start making trips to shows next year that they will begin to leak.