I have a '99 Limited with the usual 4WD problems. After searching everything on the forum, I am reasonably sure that the actuator is at fault. I talked to a dealership mechanic who thinks that this is a common problem.

Q: How difficult is it to replace the acutator? What is involved? Is there a write-up on it?

 

what have you done to troubleshoot it? what are the symptoms?

have you put it in 4wd, then shifted to Neutral on the trans while coasting and steering left to right and reving the engine? it sounds crazy, but it works. the newtral on the trans will help it to engage quicker (and helps with reving the engine). the steering right to left and back cycles the front and center diffs to help free it up. the revving the engine will increase the vacuum available to the ADD actuator and that helps as well. if you don't use it for a while, it will stick up on ya. this usually works to free mine up after sitting for months.

 

I've done all the usual things. Replacement of the actuator looms in my future. Will it be me or the dealer who does it?

Does anyone know how to R&R the acutator?

 

if you have to pull the front diff, then it's quite a job.

if you don't have to pull the diff, then it's just a couple bolts and a swap. just make sure to get the fork in the diff correctly or it won't work either.

personally, i'd do everything under the sun to get it to actuate. if that didn't work, then i'd pull the actuator LOOSE and actuate it by hand, then try again.

 

I'm thinking that mine is going to suffer the same fate. Although the next time it happens, I'll try bamachem's method.