1997 Explorer jerks & clunks at cruising speed

[Susanna65]

I have a 4 door 1997 explorer, 4.0 L SOHC, auto tran, XLT with Control Trac 4WD, with 165,000 miles. At 55 to 70 plus miles an hour, it will do a quick jerk and clunk. The tach stays the same when this happens. It happens intermittently, cold or warm. OD in on. No warning lights come on. If you need more info, let me know and I'll get it for you. Thank you for any idea's you may have.

 

[ARTURPOLAND]

what really it sounds like

is it like suspension sound or rather transmission sound. turn off the OD and check if it happens

 

[Susanna65]

More of a transmission sound. How fast can I run it out of OD?

 

[red97]

More of a transmission sound. How fast can I run it out of OD?

It won't hurt to run it with OD off at highway speeds. You will just lose some fuel mileage.

 

[Susanna65]

It does the same thing with the OD turned off.

 

[Susanna65]

Most recent update: I took my explorer to my tranny guy for diagnostic work. In a nutshelll (and I'm not very technical, but..), a code came up for the speed sensor. The transfer case bolts were loose, and the transfer case is attatched to the speed sensor wire, so the resulting play may be causing the sensor the intermittently stop working. The sensor may or may not be bad, and they will see if there is any resulting damage to the gears,etc. once they get inside. They will replace the u-joints while they have it tore apart, as they are original. May be an easy fix....or not... I'll keep you posted.

 

[CRUISERMEDIC]

i am very interested in this. i have the exact same truck and i had this type of thing happen to me. in my case it was something in the transfer case. some thing in there was causing the front axle to engage and disengage in an instant. at first it felt like i ran over a crack in the road or something but then i noticed there was no crack. i also replaced speed sensors before the t-case change. for something else the speedo was not working, but regaurdless it didnt stop the clunk thing. it might happen every 15 sec or only once in 5 miles was wierd. i had every one and their brother look into it garages included only thing any one could come up with was t-case. so i found a used on which was a biotch.....put it in and prob solved. i still have the old one i thought id keep it and do a rebuild for a spare. still aint opened it up to find the broken parts yet. let me know what they find and good luck

 

[jgavalet]

I have the same exact problem occuring in My 97 Explorer right now. I suspected something in the driveline, so today I removed the front drive shaft and test drove. The problem did not go away, actually it got worse. The transfer case will disengage at crusing speed, causing severe grinding and noise. I quickly put the shifter to "N" and it stopped, then back to "D" and continued driving fine. I put the driveshaft back on and I still have the clunk and jerk. I pulled the plug on the T-case only to find the fluid black and full of metal. I guess I know what the problem is now, but very intermitent and hard to diagnose.

 

[Susanna65]

I finally got a diagnosis and an estimate today. The transfer case has to be rebuilt. They will replace a "broken" gear and chain, etc... (I'll be more technical after I have the work order in hand) at a cost of $1285. I asked him about the speed sensor, and he said it's probably fine, but won't be sure until the transfer case is fixed. I asked him what caused the TC to go to heck, as I didn't want to repeat it, and he said I didn't do anything wrong, it just happens sometimes. Good to know.

Good news is my U-joints are in great shape, and do not need to be replaced.

I'll post the details after I pick up my rig.

 

[Susanna65]

Problem solved. Tranny rebuilt. Speed Sensor was fine. Total repair bill was less than $1,000

TFC Gasket, Bearing Kit, Seal Kit, Shift Fork, Chain & Speedo Gear = $258
Dexron III/Mercon Trans Fluid = $11.00
Lubegard - ATF Supplement = $15.00
Labor = $695

Thank you for all your help.

 

[Susanna65]

I have the same exact problem occuring in My 97 Explorer right now. I suspected something in the driveline, so today I removed the front drive shaft and test drove. The problem did not go away, actually it got worse. The transfer case will disengage at crusing speed, causing severe grinding and noise. I quickly put the shifter to "N" and it stopped, then back to "D" and continued driving fine. I put the driveshaft back on and I still have the clunk and jerk. I pulled the plug on the T-case only to find the fluid black and full of metal. I guess I know what the problem is now, but very intermitent and hard to diagnose.[See Fix Below]

 

[Susanna65]

i am very interested in this. i have the exact same truck and i had this type of thing happen to me. in my case it was something in the transfer case. some thing in there was causing the front axle to engage and disengage in an instant. at first it felt like i ran over a crack in the road or something but then i noticed there was no crack. i also replaced speed sensors before the t-case change. for something else the speedo was not working, but regaurdless it didnt stop the clunk thing. it might happen every 15 sec or only once in 5 miles was wierd. i had every one and their brother look into it garages included only thing any one could come up with was t-case. so i found a used on which was a biotch.....put it in and prob solved. i still have the old one i thought id keep it and do a rebuild for a spare. still aint opened it up to find the broken parts yet. let me know what they find and good luck[See Fix Below]