Oh Boy!!!!

1996 and up with a NP233 or NV233 transfer case all have the same capacity.

Good thing I checked, cause I got about a whole nother quart in there so I got about 2.3 not sure what happend the first time. Bad angle or something.

I Still have a whine at 40-50mph, and most times it doesnt want to come out of 4wd until I go into reverse then back into drive. I can live with this though, better then what I head before. Hopefully in time things will work better. But in the mean time any advice?

Check the vacuum actuator, the cable, and the linkage to the front axle, something is probably binding. The 40 to 50 MPH whine may just go away in time.

Check the vacuum actuator, the cable, and the linkage to the front axle, something is probably binding. The 40 to 50 MPH whine may just go away in time.


I will go check the the actuator and cable, but what exactly is the linkage?

The vacuum operated actuator is under the battery tray. A cable runs from the actuator to the right front axle housing and attaches to the differential. In the housing there are two springs, two seals, a switch, and a fork that pivots to engage/disengage the front differential. Removing the housing, (3 bolts) will expose those parts. The clutch gear, clutch sleeve, and clutch shaft are only accessible by removing the right axle housing.

The fork has a machined shaft on each end. If it does not move back and forth freely, it may not disengage the axle. The actuator is strong enough to overcome a certain amount of binding to engage, but only spring pressure moves the fork back to disengage. Here is an image of the front axle assembly, parts 15 through 22 are the fork and associated parts. http://img413.imageshack.us/my.php?image=frontdifferentialxw4.jpg

do you suggest I take that housing off and clean the fork and springs? Looks easy enough. The cable looks fine, I may spray some lube in the end of the cable just to free it up a little? Would that sticking fork cause it to shift out of 4wd hard?

Good thing I checked, cause I got about a whole nother quart in there so I got about 2.3 not sure what happend the first time. Bad angle or something.

I Still have a whine at 40-50mph, and most times it doesnt want to come out of 4wd until I go into reverse then back into drive. I can live with this though, better then what I head before. Hopefully in time things will work better. But in the mean time any advice?

Some of that may be just the way a 4W works.
Always keep a matched set of tires and go to neutral or back up a little if it is hard to get out of 4W.
If in 4W on dry payment there is a some amount of bind.

Removing the housing and inspecting the action of the fork might be a good idea. It should slide fairly freely. Keep in mind that it's sliding a clutch sleeve that engages a clutch gear to a clutch shaft. All of those parts are lubed by the axle fluid.

Several things in the front differential could cause slow or hard disengagement and/or engagement. A binding fork, binding clutch sleeve, clutch gear binding on the axle shaft, either of the two gears being worn, broken or weak return springs, binding cable, even the actuator itself could cause it. Every one of those parts move and eventually will need maintenance. Another often overlooked area is tires. All 4 tires must be the same size, preferrably the same brand. One soft tire can cause difficulty engaging and/or disengaging the axle. Keep tire pressure equal in all 4 tires.

Perhaps I should change the gear lube in the front axle. How much and what kind does it take? Where do I fill it ect? I think I will change the fluid and take a look at the springs and such.

Not a bad idea to change the fluid. The front drive axle uses SAE 80-W-90 GL-5. Capacity is 2.6 pints. There are 2 plugs, one to drain, one to fill, should be self explanatory which is which when you get under there. The front differential splits apart much like the transfer case. Unlike the rear differential where the cover needs to be removed to drain it.

I think I may have found the problem.

Ok, the problem is when trying to disengage from 4wd the transfer case does but the front diff isnt. Its holding vacum, thus the the front passengers side tire and the axle is always engaged. I noticed this even before the new tcase install. The old vac switch on the tcase was bad but with the new tcase came a diffrent vacume switch. I looked at it and it moved, I thought it seemed fine. When I pull the vacume line off of the actuator the cable is released and wheel disengages, what would cause this. Is that vac switch bad even though its not stuck. I will pull it again and work it in and out a bunch and see if that helps. But I think if that vacume problem is resolved the system would be working good.

What do you think the problem is?

If you're having the same problem with the new switch, I'd start by checking to make sure that the vent line isn't pinched or plugged.

Found problem. That vacume switch on the tcase is stuck, also when I removed it a couple drips of tranny fluid fell out of it. So I got a bad switch and tranny fluid up in it. Im guessing the fluid is probably the reason that the switch went bad.

How do I fix this.



I also changed the front diff fluid and inspected the linkage. All looked good and everything moved freely. So if I can fix this problem I should be good to go:banghead: :banghead: :banghead: .

Most auto parts stores have the switch listed under "4WD switch" in their books. Several manufacturers: GP Sorenson, Standard, Dorman, they all do the same thing. They supply or remove vacuum to the actuator when the ball is pushed or released in the transfer case. The one you have has 3 vacuum lines to it. One to the actuator, one to manifold vacuum, and one vents to atmosphere. Cost is around $35.00USD. Bring the old switch along and match it up. The trans fluid, more than likely, was sucked past the seal in the switch.

Most auto parts stores have the switch listed under "4WD switch" in their books. Several manufacturers: GP Sorenson, Standard, Dorman, they all do the same thing. They supply or remove vacuum to the actuator when the ball is pushed or released in the transfer case. The one you have has 3 vacuum lines to it. One to the actuator, one to manifold vacuum, and one vents to atmosphere. Cost is around $35.00USD. Bring the old switch along and match it up. The trans fluid, more than likely, was sucked past the seal in the switch.

So its normal to have fluid up there, just happened that the fluid went buy the ball in the switch?

Autozone has the switch for 14.99

NO, not normal. The fluid got by the seal in the switch. The switch has two problems: The ball is stuck, and two, the seal is leaking.

I realize there shouldnt be fluid in the switch, I just meant its normal to have fluid at the top of the tcase. I will try to get to autzone by this weekend or I may just order it online.

Yes, it's normal for fluid to be everywhere in the transfer case. When the gears and chain get turning, it splashes everywhere, (there is no pump).

Ok, thats what I thought. So what do you think, is this vacume switch gonna solve my problems? I am happy to have 4wd drive again but this machine in diming me to death:confused:

When the ball sticks in the "in" position, vacuum stays applied to the diaphragm in the actuator, which keeps the axle locked.

With a new switch, the ball is spring loaded to the "out" position, which vents the actuator diaphragm to atmosphere and unlocks the axle. When the encoder/motor engages 4WD, the ball is pushed in, the switch applies manifold vacuum to the actuator diaphragm, and the front axle locks.

Alright orderd the switch today from autozone, Its cheaper for me to have it shipped then to drive there for me. I live on a farm out in the country and the nearest Autozone is 60miles away. I have a little parts store in town but its quite a price diffrence compared to the ZONE. I will post results once the switch is in place. I still have that high speed whine from the tcase, I dont care as long as it works.:shakehead

Thanks everyone
paxfam

Ok put the switch on the other day, and yes the front diff is now disengageing when its supposed to but its still not popping out of 4wd right. I usually have to put it into reverse and go a few feet or it wont come out until I get up to about 50 on the highway and when is dissengages at that speed I get a loud thump. The high speed wine is still there as well.

I experienced the same, had to put it in reverse to disengage front axels. I was low on oil in front diff... filled it up and it works fine ever since.
//F

Ok put the switch on the other day, and yes the front diff is now disengageing when its supposed to but its still not popping out of 4wd right. I usually have to put it into reverse and go a few feet or it wont come out until I get up to about 50 on the highway and when is dissengages at that speed I get a loud thump. The high speed wine is still there as well.

Having to back up a little is normal on some of them.
Are you tires all matched up.
Could you be getting some tire noise on the highway?
And remember it is not good on one to run on dry payment in 4 wheel drive.

You might want to double check the vent line from the vacuum switch and make sure it is clear and free of kinks. There is a filter in the end of the vacuum line that might be partially clogged too. If that line, or filter, is restricted it would take a few seconds for the vacuum to bleed off of the actuator diaphragm before it disengages the differential.

Where exactly does that vent line go? There is like no room down there ,so if I new were the end of it was I may be able to check on it. Front diff fluid is good, I just changed it. All tires are equally wore down. I was also woundering is it okay to shift while its moving?

Look on back of firewall around dist area for vent.
A little plastic tube with a little hat on it sticking out of a hose.
Some times you can slip them in with no load on engine while moving but.
It is better to stop and put it in neutral when shifting it in.
Give them gears a chance to spline in with no pressure on them.
And also when shifting out of 4W and sometimes back up a little to release and bind up that you may get on dry payment.
Shifting into 4W low always stop and go to neutral.
Over 3 mph a shift to 4W-low will default on you.
MT