What is not staying engaged here?

[kenrunner]

I've read through previous posts and found several things that might apply to my problem and finally figured describing it and asking for input might clarify things. It started when I attempted to manually switch from 4 to 2 wheel drive ( this is an 84 SW w/auto trans. ) by going underneath and turning the nut to move the switch. I had the car on jack stands and first checked to see that is was actually in 4wd by putting in drive to see which wheels turned. To my surprise none did. I depressed the accelerator for more power heard kind of a pop and then saw the front wheels turning. Looked at the rear and they were still, which was when I realized I had not released the emergency brake. Once released, they also turned but there was now an extra noise that I can only describe as sounding like there was something loose that had not been previously. I proceeded to move switch to 2wd. Upon driving it I found that the noise increased and it seemed like the transmission was slipping as I the engine would rev rapidly while the car speed increased only slowly. My first thought was that I had done something to the transmission, but on describing the situation over the phone to my mechanic, he thought it was much more likely the problem was in the transfer case, that perhaps in trying to make the switch I something had not been fully engaged. I took his suggestion of trying to put it back in 4wd and see what happened. Sure enough it ran fine. I then tried again to put in 2wd and at first everything seemed normal but within 1/4 mile it slipped out and I had the over reving, noise and slipping on acceleration. Back into 4wd and it seems ok. Is there an easy way to get 2wd to work or should I just leave in 4? Thanks for any help. Ken

[lapoltba]

Sounds like your front axle disconnect is not working properly.  If it is disconnected while in 4wd, you will get the over-reving you described.  The Clunk was probably the splined coupler popping off the right front axle in the shfter housing.  

Take off the skid plate under the front right part of the axle and make sure your vacuum actuator is working properly.  There are posts on here that describe how to lock it in full time.  You can still use the switch on the fly functionality of the TC, driving with the front locked in does not hurt anything.  Driving with the front disengaged while in 4wd WILL  hurt the TC, specifically the viscous coupling if you have one.


* I will re-phrase and add.
Based on your last comment, driving in 4wd, then it started over revving and not accelerating, I would guess your front axle disconnect is not working correctly.  Others should be able to confirm or suggest otherwise.  I would check that first.

If you manually switched the TC from under the car, and did not rotate far enough, you could have popped into "false neutral" as well.

[eaglefreek]

If you manually switched the TC from under the car, and did not rotate far enough, you could have popped into "false neutral" as well.

That would be my guess also.

[Amc1320]

Sounds like it's not fully engaging into 2wd, mine does that as my vac actuator is "tired" stays in 4wd just fine, when I switch to 2wd in the spring I just use some wire to help it stay put, but just leaving it in 4wd wouldn't hurt anything either
if it is not fully engaged it will act like it's slipping

I would also second lapoltba and tell you to go ahead and lock the front axle, I did, one less thing to worry about messing up plus you can eliminate several feet of vacuum hose, there are several write ups about it here on the nest, it's a simple  procedue to do

[kenrunner]

The false neutral is definitely one of the things that I thought fit my symptoms. I guess I will keep it in 4wd or try to wire it in place if I shift to 2. I have seen some of the threads on locking the front axle and may review and try. Thanks for helping point me in what direction to go.
Ken

[madmax4x4]

I had the same problem a few days ago. I was going to use a carb choke cable to turn the 4w on and off but know I think I'm going to get a New vacuum can and keep everything stock. Anyone know the part numbers or who has the axle shift and transfer shift motors? I have been looking online for days found lots of good info here but no part numbers.

[carnuck]

The tcase one is the same as 84-91 Grand Wagoneers and available at http://bjsoffroad.com in the same 2 styles used in Eagles. One has 2 hose ports ('86-91) and the other has 3 ports. If you want to go to switch on the fly, permanently engage the front axle and then use the 2 port  style and you will only need 2 hoses to the dash switch, then you can remove the pin on the switch and all the other hose rubbish except the vacuum ball and hose to the switch.

[skuhler]

My 86 seems to be in 4wd all the time,  at least from the way it performs on the snow.  I thought it would be ok, except maybe for the gas mileage, is it ok that it's in? 

[IowaEagle]

Yes.  But you should trouble shoot the issue when you can.  My guess is the s TC case shift motor is not functioning as it should.  Either a vacuum issue or a bad TC shift motor.

[carnuck]

When I got my first Eagle wagon, I thought it was in 4x4 and drove everywhere all winter. Come spring I tried to drive up a little muddy hill and only the rear wheels spun. When I looked under the dash ALL the vacuum hoses were missing!