Transfer case diagnosis?

98ExplorerGuy · 05-27-2007, 03:01 PM

It's hard to know where to start with this, so I apologize in advance.

1998 Explorer XLT with 4L V6 ("E" in the VIN code) engine and full-time AWD (Auto, High, Low, control knob). About 150k miles.

The engine developed a "tick" at around 120k but ran reasonably well. At 130k the tick worsened and then one day became dramatically worse, ran very poorly, and significant loss of horsepower. Honestly, I thought it was a collapsed lifter kind of problem.

I took the vehicle to the mechanic son of a co-worker. This guy is pretty sharp, has worked as a pro mechanic but now works out of his home garage. He likes to party and not working a "real job" permits him to set his own hours and take as many or as few jobs as he wants at any given time.

So, anyway, he got into the engine and quickly found that virtually every one of the internal timing chain guides (there's *five* timing chains in this engine!) was broken along with a few non-working tensioners. The truck is in good shape otherwise, so we went ahead and installed new timimg chain assemblies (guides, chains, tensioners, etc) and the engine now runs like new.

Okay, on to the transfer case. While he was rebuilding the engine, I told him the only other issue was a repeating "clunk" sound from the area of the left-front wheel and pretty much only on hard acceleration, especially uphill or into a left turn. The clunk sound, though repetitive, did not strike me as being one-for-one with wheel revolutions, for what it is worth.

Right off, he points out that someone in the past removed the transfer case actuator (my term, not his) and tied it off with a peice of heavy wire. I have to assume that a dealer mechanic did this because no one else has ever worked on it; I have no recollection of the dealer ever discussing transfer case issues with me.

After more examination, he concluded that the transfer case is stuck in 4WD mode and the clunk is caused by the forced rotatation of the front wheels. We (well, I) decided to let it go for the time being as it was almost totally controllable simply by avoiding hard acceleration.

Almost finished; I promise.

A few weeks ago my son picked up a large chunk of metal debris with the right-front tire necessitating a replacement. The two front tires (one new, one not-so-old) are no longer evenly matched with perhaps 1/8 inch or a little more difference in tread depth (same brand and style however).

The noise coming from the left-front wheel area is now much, much, worse. Though not quite the clunk-clunk-clunk of before, it is now an almost constant rattle which is there on both hard and light acceleration and even on downhill coasting (never before while coasting). I am concerned to the point that I stopped driving the truck at all for the time being.

I discussed it with my mechanic who is convinced the this is the same transfer case issue as before, exacerbated by the now different wheel diameters. His suggestion is to try to find a transfer case at a salvage yard and swap it out.

Any other sugestions out there?

98ExplorerGuy · 05-27-2007, 03:27 PM

FWIW, I found the sticky thread on "4x4 Shift Motor Rebuild" and it reminded me of something - I am somewhat certain that my mechanic told me he tried turning the selector shaft manually to at least get the case into 2H mode. As I recall, he said it didn't want to move and he was concerned as to how much torque he should have to apply. Not having done this before, he didn't know if it should turn easily or require a hard pull on a six-foot long bar, if you know what I mean.

How much torque should it take to move the selector shaft by hand?

05-27-2007, 03:01 PM	#1
98ExplorerGuy Wannabe Elite Explorer Join Date: May 2007 Posts: 18 Vehicle Specs (Original Poster)	Transfer case diagnosis? It's hard to know where to start with this, so I apologize in advance. 1998 Explorer XLT with 4L V6 ("E" in the VIN code) engine and full-time AWD (Auto, High, Low, control knob). About 150k miles. The engine developed a "tick" at around 120k but ran reasonably well. At 130k the tick worsened and then one day became dramatically worse, ran very poorly, and significant loss of horsepower. Honestly, I thought it was a collapsed lifter kind of problem. I took the vehicle to the mechanic son of a co-worker. This guy is pretty sharp, has worked as a pro mechanic but now works out of his home garage. He likes to party and not working a "real job" permits him to set his own hours and take as many or as few jobs as he wants at any given time. So, anyway, he got into the engine and quickly found that virtually every one of the internal timing chain guides (there's five timing chains in this engine!) was broken along with a few non-working tensioners. The truck is in good shape otherwise, so we went ahead and installed new timimg chain assemblies (guides, chains, tensioners, etc) and the engine now runs like new. Okay, on to the transfer case. While he was rebuilding the engine, I told him the only other issue was a repeating "clunk" sound from the area of the left-front wheel and pretty much only on hard acceleration, especially uphill or into a left turn. The clunk sound, though repetitive, did not strike me as being one-for-one with wheel revolutions, for what it is worth. Right off, he points out that someone in the past removed the transfer case actuator (my term, not his) and tied it off with a peice of heavy wire. I have to assume that a dealer mechanic did this because no one else has ever worked on it; I have no recollection of the dealer ever discussing transfer case issues with me. After more examination, he concluded that the transfer case is stuck in 4WD mode and the clunk is caused by the forced rotatation of the front wheels. We (well, I) decided to let it go for the time being as it was almost totally controllable simply by avoiding hard acceleration. Almost finished; I promise. A few weeks ago my son picked up a large chunk of metal debris with the right-front tire necessitating a replacement. The two front tires (one new, one not-so-old) are no longer evenly matched with perhaps 1/8 inch or a little more difference in tread depth (same brand and style however). The noise coming from the left-front wheel area is now much, much, worse. Though not quite the clunk-clunk-clunk of before, it is now an almost constant rattle which is there on both hard and light acceleration and even on downhill coasting (never before while coasting). I am concerned to the point that I stopped driving the truck at all for the time being. I discussed it with my mechanic who is convinced the this is the same transfer case issue as before, exacerbated by the now different wheel diameters. His suggestion is to try to find a transfer case at a salvage yard and swap it out. Any other sugestions out there?

05-27-2007, 03:27 PM	#2
98ExplorerGuy Wannabe Elite Explorer Join Date: May 2007 Posts: 18 Vehicle Specs (Original Poster)	FWIW, I found the sticky thread on "4x4 Shift Motor Rebuild" and it reminded me of something - I am somewhat certain that my mechanic told me he tried turning the selector shaft manually to at least get the case into 2H mode. As I recall, he said it didn't want to move and he was concerned as to how much torque he should have to apply. Not having done this before, he didn't know if it should turn easily or require a hard pull on a six-foot long bar, if you know what I mean. How much torque should it take to move the selector shaft by hand?