Transfer case

[ernaldmerican]

I will try my best to explain the situation. I have a 1998 ford explorer V6 SOHC automatic with 195,000. Car runs great thanks to the efforts of those in this forum.

My problem is this, while driving I hear a knocking noise (but no jerkyness) just a slight knock and only once. Than it will happen again just once some time again in the next 5 or 10 miles. It is not consistent when the noise happens.

There is no conncetion to rpm, what gear Im in (its an automatic) whether its in OD or not.

I went and experimented with 4x4 high and auto. It happens in auto, but does not happen in 4x4 high. I took the car for a 100 mile run in 4x4 high (it was snowing) so i felt okay going that long in 4x4 high, and had no noise. When I got where I was going I took it out of 4x4 high and after about 3 miles I heard the noise just once.

I'm wondering if the solenoid( I believe its what engages the front drive system) in the transfer case is trying to go into 4x4 high even though its in auto, not sure grasping at staws.

any thoughts.

 

[dogfriend]

http://www.explorerforum.com/forums/showthread.php?t=170068&highlight=transfer+case

There is a failure mode where the bearing support for the shaft in the transfer case gets distorted. This will allow the gears to sometimes go out of mesh, causing the thump. You may have that problem.

 

[ernaldmerican]

Thanks, and threads that your aware of in the forum that show how to remove / replace?

 

[96eb96]

Thanks, and threads that your aware of in the forum that show how to remove / replace?

Chances are you have a mechanical issue, but another cheap thing you can try(can't hurt) is to change the fluid in the tcase if it was never done. Takes a quart and a half of regular mercon transmission fluid. This job is very easy, all you need is a flex funnel.