what's the standard for putting a 90 YJ in 4 wheel drive? Do you have to be stopped and in neutral to shift into 4 wheel or can you be moving?

thanks

I think that you can be moving slowly, but in my 91 I always stop. It is just easier on the drivetrain. I stop, push in the clutch, shift into 4wd. And I usally will just sit there for a couple of seconds just to insure that the fork in the axle has fulling ingauged. And then off I go. I use the same steps when I take it out of 4wd.

The vac fork junk in a YJ is that... Junk [img]images/graemlins/bs.gif[/img] If you are having problems with your 4wd there is about a 90% chance it has to do with vac.

With my automatic, I stop, shift into neutral, take my foot off the brake, allowing the Jeep to roll a little bit, then shift, allows all the teeth in the gears to find their place without being bound up by being held in place.

If you are pulling the lever back and you know you are not getting the front end to shift, as Olin said, start with the Vacuum lines from the t-case to the axle, if they are melted broken or nicked causing a leak the fork will not move.

Thanks lomod and Olin. I was having a bit of trouble shifting so I thought I'd ask before I ruin something. It's a 5 speed. Engine, trany and everything else is stock, I think. I'm still checking everything out.

Olin's method is conservative and good to use. The 231 transfer case is syncronized so you 'can' shift on-the-fly. I don't know how well this works as I've never shifted one. To go to low range though, you need to stop, press the clutch, (maybe roll by gravity slightly) and shift.