Engine/Transmission (1994 - 1998) 4 wheel drive trying to engage while driving!

[Got Smoke?]

Ok people I'm having a major problem here. It seems my 4 wheel drive is trying to engage while driving down the road.



This started happening about a 2 or 3 weeks now I guess? You would hit a bump in the road and either one side or the other would start whining really loudly like a hub was going out. Well I took it to my local shop that I have my work done at. They looked it over and replaced the pass. side hub under warrenty(I had both done last year). Well after that hub replacement the problem was still evident, and got worse as time went by. Finally I arranged to leave my truck with the shop for a few days to let them look it over.



What they discovered was the 4wd trying to engage when hitting a good size bump in the road, and that if you pull back slightly('bout 2" or so) on the 4wd lever it will quit. So they said they bench tested my actuator on the front axle and it seemed ok. They told me that it needed a new vaccume switch, but by this time I had to have my truck back so I replaced the vaccume switch on the transfer case myself and the problem is still there. After talking with the shop they seemed to think its a loss of vaccume somewhere causing the actuator to try and engage? Does that make sense?



I was getting my truck ready to sell because I want a club cab, and now this kink has been thrown my way. Does anybody have any idea what could be wrong with my 4wd system

 

[willyslover]

might want to give these guys a call. . nice folks to chat with in Oakland



TRANSFER Case Express

2969 East 7th Street

Oakland, CA, USA 94601

and

205 Jones Road

Spartanburg, SC, USA 29307



1-800-MUD ROAD

Toll Free

(1-800-683-7623)

 

[JGheen]

What did you find out?

Any findings of your 4WD issue??

 

[Got Smoke?]

Well I unplugged the actuator on my way home last night and the problem still exsists.



How can this be happening if the vaccume is disconnected to the front actuator? :{

 

[Rob Thomas]

Mark, the problem may be a worn shift fork. An uncle of mine had this happen on his about 2 years ago... ..... on the e-way, 70mph, just fell into 4x4, when that happened, the chain broke, among other things, it was a mess. The cause was a worn fork. Good luck.



Rob

 

[Got Smoke?]

Originally posted by Rob Thomas

Mark, the problem may be a worn shift fork. An uncle of mine had this happen on his about 2 years ago... ..... on the e-way, 70mph, just fell into 4x4, when that happened, the chain broke, among other things, it was a mess. The cause was a worn fork. Good luck.



Rob

Rob what about a mis-adjusted shifter? Because I know the adjustment got messed with on the last clutch install, however I looked at it and it appeared ok Doesn't explain why you pull the lever back and it quits though

 

[Rob Thomas]

I wouldn't think that even being misaligned would cause your problem, unless the shift lever was binding somewhere. When you have the t-case rod removed, the shift lever is free swinging, it's doesn't have shifting/engagement in the console area, it's all done in the t-case. Therefore, even if it was slightly out of adjustment, it would'nt matter, other than the lever may touch the console fore or aft, which you say you can pull the lever back some, so IMO your fine there.



BTW, why do you mess with the shifter adjustment when pulling the t-case/trans? Just lube the shift pivot at the plastic grommet and pry out, simple, easy, and doens't move the adjustment, FWIW.



Rob



Another thing about the fork..... on the ends of the forks, there is a material (I think nylon or similar) it does wear out, I can find the old worn fork around here, and get you a pic if you want.

 

[SBrandon]

before you spend a ton of money

Before you go out and spend a metric ton more of money, do one thing first, Take out the front drive shaft. put a separation between the transfer case and the front axle. Disconnect the two vacuum lines on the vacuum actuator. (it only engages when vacuum is applied to it) then drive it.



You have me a little confused here, you speak of replacing front hubs? do you mean wheel bearings...



I don't think anything will be wrong with the transfer case but it may. Shift forks dont wear, they have nylon pads on them, and if they come off you do have problems. How does it feel when you lock it in (crisp and positive or does it fight) before you do what i suggested above go find a loose dirt road, put it in 4x and go down it at about fifty. see how that sounds if it whines and grinds you surely need to pull the drive shaft.



Other than that lift the front and feel for free play in the tires, how do they sound as you spin the tire. And last but not least completely check your BRAKE CALIPERS. process of elimination.