Solved Another Transfer case question

[Mr. Alligator]

I have a 1997 Explorer 4.0 SOHC with automatic transmission. Recently, “4wd 4lo” dash lights began to flash six times every few minutes. Also, the front end often has slight to moderate grinding/binding around slow turns. There are lot of posts about this issue, and some report the exact same symptoms. But almost all of the threads end without resolution. Thank you for your consideration….

Four wheel high and four wheel low respond to the dash switch properly for a few miles after start up, then the dash lights flash and the four wheel drive no longer responds. The grinding/binding through turns occurs before and after the flashing and regardless of dash switch selection.

The transfer case can be shifted to four wheel drive in the first few miles, before the dash lights begin flashing. After the dash lights flash, the truck will stay in 4h,but no longer responds to any switch commands.

I have checked fuses suggested on this Forum, then had the transfer case rebuilt. I assumed the transmission company that rebuilt the transfer case changed the speed sensors (but I have not asked, yet). The transmission company believed this was a mechanical, not an electrical issue.

Then I replaced the drivers side hub assembly, as the binding seemed to be primarily from the drivers side. This did not result in any improvement.

I also removed the transfer case shift motor. It appeared to have parked leaving the directional shaft about 80% of the way toward 4h. Using pliers, I manually rotated the shaft the rest of the way to 4h, and drove with the shift motor removed from the transfer case. Still, no improvement.

Oddly, after the dash lights begin flashing, the front wheels do not engage (unless 4h was already selected), BUT the grinding/binding continues unchanged.

Dang. Any ideas?

 

[410Fortune]

Sounds like your control trac t case is toast

Drain the fluid and have a look at it. Usually you will find white nylon bits in the bottom of the case when the fluid drains out
The “guides” break leaving you with a bad t case
You have a few choices for fixing it just make sure if you get a newer good used t case that you must retain the rear speed sensor since yours is a 97

 

[Mr. Alligator]

Thank you for your consideration. That would have been my prediction. But the transfer case was rebuilt by competent transmission shop, and symptoms did not change at all.

The front end grinds slightly to moderately through turns, and sometimes pops. After a few miles, I think the four wheel drive system detects a problem, flashes dash lights, and locks the four wheel drive controls out.

What else could cause a grinding type problem in the driver’s side front end that would be shortly be detected by the four wheel drive system? I have replaced the front hub and bearing assembly, and have removed the transfer case actuator which turned with the selector switch …. except that it it did seem to be parked about 80% of the way in the direction of “4h”. I moved the transfer case with pliers, ran the truck without reattaching the actuator motor, and it also made no difference. The CV joints were both replaced two years ago... but since we often get such poor quality parts that this may still be a problem….

Any more ideas? Thank you for your wisdom.

 

[410Fortune]

Sheesh that is a tough one
Usually with a noise that bad something will be obvious when the front end is put in the air and you give it a shake down test
Sounds like a cv axle to me, the way you describe that
It could of course be in the differential too?

 

[Mr. Alligator]

Thank you again. CV joint or front differential are my primary suspects now. I will get this fixed, and I will post the solution.

Thanks!

 

[Mr. Alligator]

SOLVED: Alright, I have my (embarrassing) solution. The transfer case was getting faulty signals from the …. ****** Rear output speed sensor on the transfer case. Dang!

From my readings, I thought that speed sensor issues would cause an inability of the truck computer system to communicate and operate, then just flash series of dash lights to let the driver know the system is not working correctly. I did NOT think speed sensor failure would cause binding in the front end. Have seen front hub assembly failure cause grinding that feels like the truck is stuck in 4lo. Have seen speed sensors failure result in flashing dash lights and no four wheel drive control.

But NEVER saw this before, and I have read any posts that describe this. But the issue makes sense. So there…. Back on the road WITH no binding, no flashing dash lights, AND operational four wheel drive.

Drive safe.