I saw there's a thread similar to this out right now but I have a slightly different problem and I don't want to hijack that issue.

My problem is that my 4high will engage but often it will disengage and begin to grind once I start to accelerate and move around. The problem is unpredictable because sometimes it works great and sometimes it won't even engage at all. What should I do? What's the problem? Thank you!

 

Like its trying to engage sound? becaue i Just swapped my shifter fork and diaphram. mine is a vaccum shifter. yours should be too if its a 92. I didnt have the grinding noise....BUT i had sooo much slop in my shifter fork that sometime my 4wd would engage and sometimes it woulnt. when i took the shifter fork out i could wigggle the fork alll the way foward and alll the way back. I have a feeling mine was jst wiggling in and out of 4wd.....aybe that is our problem