1990YJ suddenly no 4 weel drive??

Hi John,

The 'small boulder' effect was probably due to the splined collar grinding away on the edge of the inner axle because your vacuum diaphragm failed and couldn't fully pull the collar away or your aluminum fork is worn and has too much lateral play on the shift rod.

If your splines are still intact and the fork isn't too sloppy, make your own manual shift. Mine was built for $0 with scrounged parts:

1. Arch a small steel plate to cover the aluminum shift housing. Drill it so it uses two of the existing aluminum cover's bolts.

1. Weld two nuts on the plate such that the shift cable and casing can fit straight through the two of them. Leave a gap between the nuts for a small hose clamp to secure the cable casing.

2. Drill a hole across a bolt so that the uncased end of the cable can pass though. After removing the vacuum diaphragm thing, weld this bolt (perpendicular) to the shaft that pushes the shift fork. Put two nuts on the bolt, leaving a gap between them so the drilled cable hole is exposed.

Assembly:

1. Scrape the mating surfaces of the fork cover and axle housing clean and apply gasket goo. Line up the fork with the shift collar and bolt the cover, with your steel plate, to the axle housing.

1. Drill a hole in your firewall above the gas pedal. Fit a grommet and fish the cable through.

2. Fix the cable handle end to the underside of your dash with a bracket and shove the handle full home.

1. Route the cable end to your shift assembly. Ensure you have enough slack to allow for full drop of the axle then cut to fit.

2. Strip a few inches off the end of the cable casing. Pass the cable through the nuts on your plate and insert the bare end into the bolt on the shift rod. Make sure your cable handle is pushed home and that the fork rod is pushed all the way to the right. Tighten the two nuts on the cable end and tighten the hose clamp on the casing.

Steve

JohnE.P.--JEP wrote: