Help with strange transfer case binding

[Habitat0927]

Hey guys, great forum!

Last week I purchased a 2002 Explorer XLS 4x4 with 230k for $400 and have been working through a "fix-it" list to get it roadworthy again. This forum has been a great source of information on this vehicle.

When I purchased the truck, the 4WD did not function at all. No lights, no clicking, nothing. The truck ran perfectly, but it was RWD, the 4x4 Auto would not engage. Based on what I read here, I went to my local dealership and bought a 4x4 control module. I connected the new module up this morning and was thrilled when I pressed the buttons on the dash and cycled the transfer case through 4x4 Auto, 4x4 High, and 4x4 Low. It seemed like a successful fix until i tried to move the vehicle.

My Explorer will roll off fine up until about 10mph, when I feel the front axle binding up and all sorts of popping and grinding. This is so violent that i havent dared try to drive more than 50 yards from my driveway or any faster than 10mph. The problem occurs mainly when driving straight, forward or reverse, but will ease up a bit when i drive in a circle around my cul de sac. It also occurs regardless of whether im in Auto, 4High or 4Low. The power is getting to the front wheels, but not smoothly.

Prior to replacing the 4x4 Module, the vehicle ran smoothly and I did not notice any sounds coming from the front differential, bearings or CV shafts. I have replaced the new 4x4 module with my old, nonfunctional one, and the problem goes away, albeit at the expense of my 4-wheel-drive. I would assume that my problem is the clutch in the TC locking and unlocking, but I don't know where to begin troubleshooting. I have read that front wheel bearings and tires can cause problems like this, but I find it hard to believe that they could cause the transfer case to act like its going to explode.

Have any of you experienced similar problems? Perhaps a Hall Effect sensor is out? I appreciate any advice you can offer me!

 

[hpd217]

2 main things to look at first being your tires. Make sure they are worn evenly if they aren't that will definitely cause binding. The other thing it could be (and I hope its not for your sake) is the viscous coupler. This is located in the transfer case and runs about 400 bucks to replace. Hope this helps.

 

[Habitat0927]

Thanks for your advice. I have checked the tires and they are the same brand/size and all seem to be in fairly decent shape, but i have not tried rotating or measuring them to ensure that they are identical. I will try that next.

You mentioned a $400 cost for the transfer case coupling. Is that for just the part or a complete install by a mechanic? I am a pretty good wrench, but disassembling the entire transfer case seems to be a little more time consuming and frustrating a job than id be willing to take on.

 

[hpd217]

actually the coupler is 300 from STE Couplers(look them up on the web). Once you pull the tc its only a matter of pulling the old VC and installing the new one, its not very difficult at all.

 

[IZwack]

Let's get one thing straight here:
If the vehicle has the AUTO/HI/LO selector and lights (as mentioned by the user), then the transfer case is NOT the All-Wheel Drive (AWD) transfer case and therefore does not use and does not have a viscous coupling device.

As for the binding issue, this situation is just like most of the other transfer case "binding" threads - so search and I'm sure you'll come up with a ton of info and hopefully some diagnosis steps. And the binding issues discussed in the 2nd generation forum apply here since the transfer cases are mechanically very similar in operation.