4 Wheel drive problem

[zero]

I just found that the 4 wheel drive in the 94 sport I just bought doesn't work. Neither 4High or 4Low. What are the most common problems with these models? what are a few simple tests that I can do to determine the location of the problem?

 

[Rollin Thunder]

Most likely the switch (if yours is not a lever) They are prone to do that.

 

[zero]

It has manual linkage to the transfer. Is there an electric switch to engage the hubs?

 

[95TwinTT]

The actuator to engage the front wheels, is on the passenger side of the front axle housing. The manual shift console has a light that comes on when the front axle has engaged. It does not happen at the exact same time you pull the lever. It waits until there is no stress on the system.

The unit may have to be replaced. First I would make sure the wires are all hooked up under the truck. They are in a bad spot for corrosion. It’s possible the contacts just need to be cleaned up in the plug next to the unit. Good luck……….. :cool2:

 

[zero]

"95TwinTT The actuator to engage the front wheels, is on the passenger side of the front axle housing. The manual shift console has a light that comes on when the front axle has engaged. It does not happen at the exact same time you pull the lever. It waits until there is no stress on the system.

The unit may have to be replaced. First I would make sure the wires are all hooked up under the truck. They are in a bad spot for corrosion. It’s possible the contacts just need to be cleaned up in the plug next to the unit. Good luck"

I will check that out today. I don't think that I am getting a light after shifting into 4WD. Any other common problems with these models?

 

[zero]

I checked and cleaned the connections to the actuator but the 4WD light still is not coming on. Is there a fuse or relay that can be checked?

 

[95TwinTT]

There should be a fuse under the dash, left side of steering column. Looks like second row, second fuse is for 4WD.

Have you done a over all inspection of the front drive system? All the linkage is in place and nothing looks like it has been modified?

If the transfer case is in 2 wheel drive, you should be able to turn the front drive shaft by hand. I guess first things first, if you shift into 4 wheel drive, try to turn the drive shaft. (with the engine turned off and in Park) It should be locked into gear and not able to turn. If that is the case, then it has to be the actuator on the front axle.

I would try putting it into 4 wheel drive with the ignition turned on, but without the engine running, check for voltage at the actuator under the truck. Let us know what you find..............

 

[zero]

I think it is a wiring problem, but I cant seem to find it. I have no power to the actuator, so I checked the switch on the top of the transfer case (right above the linkage) with the igintion on and there is no power on either wire. I checked at the fuse panel and I do have power of the 4WD fuse. I believe I need 12Volts of power from the igintion switch to the transfer case switch, then once put into 4WD the switch in the transfer case sends power to the actuator. Does this sound correct?

I started looking under the dash and it is a wiring nightmare. It looks as tho someone may have stolen my hoe before, as it is hard to find a wire that is not spliced! I'm not a wiring guy...so this is gonna be tough.

 

[zero]

I found a schematic on the web, but I'm not sure if it is for my exact model. It is showing a trasfer case relay in the system. Does anyone know were that relay would be located?

 

[95TwinTT]

There are many different schematics available for these trucks. I have been looking at the schematic in a haynes manual. I does not show much for the 4WD system. All I can find is a input to the ECM that tells the computer that it is engaged. That is a gray wire with black stripe. The schematic has a arrow pointing to a box marked "transmission system".

You might have to go to the public library and get the real schematics. The ones that have all the details.

The good news is that the wire colors can get you back together if someone has messed with things.

Often, there has been a alarm/car starting unit installed and removed. That can be a mess if they were not careful.

I don't remember for sure, but I thought there was a power source at the axle that was switched on the actuator to light the lamp in the console. My 95 is in storage for another week or two. If you still having problems then, I could check mine to give some hints on where those wires should be.

I would check the wire colors at the switch at the console and look under the dash to see if that color wire has any splices. It's worth a try.

Wish I could be more help. Good luck..........

 

[zero]

95TwinTT, you were right it was a messed up wired due to the old owner removing an alarm system. I now have 12V all of the way to the actuator, but still no 4WD. I pulled the actuator out and it is not activating. I am buying a new actuator tonight.
Anyone know how high the differential fluid level should be? I was expecting to lose a bit of gear oil when I took out the actuator, but I didn't.

 

[95TwinTT]

I now have 12V all of the way to the actuator, but still no 4WD. I pulled the actuator out and it is not activating. I am buying a new actuator tonight.
Anyone know how high the differential fluid level should be? I was expecting to lose a bit of gear oil when I took out the actuator, but I didn't.

Nice work. If you remove the fill plug, you should be able to touch the gear lube with your finger reaching in the hole.

 

[zero]

I topped the diff. fluid off and replaced actuator.......and now the 4WD is working fine! The wiring was quite a pain, however I learned a little and saved some coin. Total cost $87.00... and three evenings of blood, sweat and beer

 

[95TwinTT]

Congrats! It's a great feeling to save a few hundred bucks, plus you get to know your Hoe a little more when you do it yourself........ :thumbsup:

 

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I'm going to add to this thread since its what I've been following. Hope this pops up for someone to see. So, In checking the fuses, the 4WD fuse was blown so I replaced it but the 4wd would still not activate. I was about to check the wiring to the actuator when I found a lot of smoke coming out of the actuator where the wiring goes into the mechanism. My assumption is that the actuator is bad since it appears that power is getting to it but something is binding or not working properly and causing the smoke. Before I go buy the part are there any other things I should check?