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scott howard 02-01-2011 02:08 PM

By-Passing Frt. Diff. 4wd Vacuum
I have been asked by a few folks to explain how to do away with the vacuum part of the 4wd engaging motor on the frt. diff. that is such a weak link.

1. jack up right frt. tire and place on jack stand
(easier if not done on a day that snow is not packed on your

2. unplug vacuum lines from the shift motor actuator and cap off you will not need them any more .

3.remove the four bolts holding shift motor on and remove it
(don't forget to have a pan or towel on the floor to catch the very
amount of lube that will come out) look at the axle see how the collar slides over to connect the two axle's together? you might have to turn the right tire a little as you use your finger to slide it to left all the way as the splines line up
now your frt. diff is locked into fwd. ( that's a good thing for a jeep) take apart the shift motor.take a marker and put a dot on one side of the fork and a dot on the matching side of the housing so you will remember what way the fork faces( trust me it saves remove the two e-clips holding the
shift fork shaft in place and pull shaft out. discard everything but the shaft,fork and big e-clip put the shaft with the fork back in the housing (no e-clip yet)
and move the fork all the way to the right that is where it is when the 4wd is locked in ( remember the collar you slide to the left to lock the axle's together?)

7. now get a spring or fuel line (like i did) and cut it to take up the space on the shaft so that the fork can not move to the right ( and yes the spring or hose needs to fit over the shaft and I am sorry i did not measure the length or i.d for ya but heck you need to do a little of the work yourself) tip: if you use a piece of hose it needs to be fuel and oil resistant ( mine has been set this way for two years)

8.after you get the spacer cut right put in the e-clip so the shaft won't come out.

9. reinstall on the diff. using a little gasket sealer or a new gasket and your almost done. top off the lube if you feel like the little bit that came out is a bad thing.

10. you are now done and have a much improved 4wd set up.
you will not notice a drop in mpg, no change in handling ( transfer case disconnects the frt. drive). what you will feel is a good feeling knowing your frt. axle really is locked in when it's needed ( yep even when it is -7 degree's like it is here to day)

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