4wd not working

[mfulaytar]

I recently had my transmission rebuilt and since i got it back my 4wd has ceased to work. and i know this because when my buddy called to me to come pull him out i also got stuck. so i take it back to the shop and they tell me that my vac lines and actuator are all full of mud and that they would blow them out. i told them to go ahead and replace the vac lines. still no 4wd. when i am in 4low (or at least when the 4low button is illuminated) i can hear the whining noise that i assume is my front differential, but the front wheels do nothing. they want around $100 to replace my 4wd actuator and they say that should fix it. I know i can do this myself, but before i dive in i just wanted to see if im missing anything or if im headed in the right direction.

thanks guys

[HenryJ]

Have you replaced the transfercase switch? If not read the sticky. Next check your vacuum lines behind the brake booster for dry rot. While there check to see if the line to the reservoir is connected in the left fender. All that good? Disconnect both battery cables wait three minutes and connect them back up to reset the module.
Now tell us about the lights Check to see if the front shaft is locked in when you shift to 4x4. Check the actuator cable to make sure it is not sized.

Lots and lots to check before you start replacing parts

[mfulaytar]

read that that sticky and now im scared to death. i do have that hissing sound sometimes, but when i switch to just floor heat, some air still comes out of the vents for a little while and then it stops, and the hissing noise is constant. im going to get get a new transfer case switch and throw that on and see if that does the truck. its always something....

[mfulaytar]

well i bought the new transfer case switch and what i pulled off my truck doesnt look like what ive seen on here.

[HenryJ]

Ok, that is the front differential switch. It is electrical and lets you know when the collar has shifted engaging the front axle. The transfercase switch is a vacuum switch on the transfercase.

That hissing is a vacuum leak and probably why you do not develop enough vacuum to shift the front axle. Dry rotted hoses are common, as is the hose to the reservoir falling off or getting dislodged accidentally. HVAC controls failing and leaking can be a problem too. You are going to have to snoop around and find those leaks.

[mfulaytar]

I found a vac hose that wasn't commected to anything. I'm not sure where it's supposed to go, I can't find anything. I've searched high and low for the transfer case switch and I cant find it. Also, I pressed the 4low button and put it I'm drive and stepped out while it rolled. When I looked under, I saw my front drive shaft spinning. So atleast I have that going for me.

[HenryJ]

Feel for a nipple just under the lip of that fender. That is to the vacuum reservoir and the heart of your problem

[mfulaytar]

well i reattached the vac line. it fits pretty loose so i guess ill need to replace that. 4wd still doesnt work. i suppose that ill have to find the t case switch and replace that. i still hear a hissing noise when i put the ac selector on just the foot setting. i saw on the s10 forum that people were taking apart literally their entire dash to get to the vac lines for hvac. i really hope it doesnt come to that. thanks for your continued help.

[LoneWolf04]

I would replace all the vac lines you can see on top of the motor to start. Looking at the line you have its toast and disintegrating in your hand. Looks swollen as well and I'm sure the other ones connected to it are in just as bad of shape.

[okaussiee]

I would take a piece of vac hose and attach it from a vacuum source directly to the front wheel actuator under the battery. Raise up the right front wheel, start it up, put it in 4WD. Then check the front driveshaft to see if it is locked. If it is, then check the right front wheel for the same thing. If IT is, you have 4WD.

You just took the Transfer case out of the loop and possibly eliminating it as the problem.

Mine is a 2002 and I can't get my big hands on the switch and had to change it twice. Both times I had to take it to a repair shop who had smaller hands than mine to change it.

If the front driveshaft is locked and the right front wheel is not, check the front actuator and its cable to the front differential. The diaphragm in the actuator could be bad, or the cable to the front differential has problems. It may need to be replaced.

All of these tests I have done to mine to fix my problems. Hope this helps...


Bill

[mfulaytar]

Thanks a lot guys. I really appreciate the help.

[mfulaytar]

Well I pulled my actuator and the cable and I'm pretty sure both are just fine. Seems like the actuator is holdi vacuum and the cable slides pretty easily. Is it worth replacing them anyway? Tomorrow Im going to have my vac lines replaced, well the ones I paid for but they didn't do. Also I'm gonna have my mechanic put that tcase switch on for me.

[mfulaytar]

UPDATE: i had that switch installed and at first my 4wd still did not work so the mechanic "adjusted" the actuator cable and everything worked great. went in and out of both 4hi an 4low perfectly. Later that night, on my 7 hour drive to north Tennessee, i hear a weird whining noise. i pressed the 4 hi button and it stopped, went back to 2hi and it started making the noise again. i pulled over and what i deducted was that my 4 wheel drive was still half way engaged if you will. After many attempts to disengage it by shifting in and out both the high and low range, i ended up puling my battery and actuator out. i disconnected the actuator cable and pulled on the end a few times to maybe try and get it unstuck. put it all back together and shifted to 4 low and then back to 2hi and i never had a problem the rest of the trip or the way back. except for now my 4wd doesnt work. AGAIN. this is frustrating. i think im going to replace the actuator cable and see how that goes. any thoughts?

EDIT: turned the truck on and pulled the battery and tray out to take a look. i noticed the vacuum hose wasnt connected so i reconnect it thinking i found my problem. nope. more noises when driving around. so with the truck still on, i look in and the actuator looks like so but i am in 2hi

so for kicks and grins i press 4hi and it looks like this

from what i read here http://www.s10forum.com/forum/f220/4x4- ... nd-506164/ i think maybe my brand new transfer case switch is defective. so i guess ill put a new one on and hope the gears in my transfer case arent all stripped out. im thinking that the reason the noise stopped on my road trip was because i forgot to connect the vac hose back to the actuator.

[ApproachMedium]

I would try the cable first. If the cable is jamming up inside, it may not travel right. If the 4x4 is OFF and its still holding vac in the actuator there may be a bad switch on the T case or a squashed line. Check your lines out first. If the actuator is fully letting go with 4x4 off and the vac line detached it is nothing wrong with your actuator or vac lines, it is the cable.

EDIT:

Just looked at the pictures closely, your vac line on the T case is probably on wrong or something. It looks like its engaging the vac when the 4x4 is off and disengaging it when the 4x4 is on which is the opposite of what you want the truck to do. Nothing is wrong with your actuator, and probably not the cable either.

[rlrnr53]

Check the lines on the transfer case switch. I have seen them turned and forced on the switch, which can lead to a noise like you have.