Something wrong while highway coasting

[talegatefisher]

My 02 Explorer 6cyl. has been acting strange lately.

If I and driving within or over 65mph and remove my foot from the gas peddle completely, My truck begins to repeatedly clonk within the drivetrain. It then stops or corrects itself as soon as the gas is reapplied.

To try to explain the meaning of clonking is best discribed as a sharp repeat tugging of a rope feeling. Every once in a blue moon the check gauge light may come on (May not be related) but the mechanical problem is always there; actually up hiil or down.

Have no idea what it could be. I searched the Haynes book through and found nothing. Not even in the trouble shooting section.

Any help or idea is appreciated!
Afraid to drive it and cause more serious problems.

Has anyone else experienced this with thiers?

 

[quicksix]

My 02 Explorer 6cyl. has been acting strange lately.

If I and driving within or over 65mph and remove my foot from the gas peddle completely, My truck begins to repeatedly clonk within the drivetrain. It then stops or corrects itself as soon as the gas is reapplied.

To try to explain the meaning of clonking is best discribed as a sharp repeat tugging of a rope feeling. Every once in a blue moon the check gauge light may come on (May not be related) but the mechanical problem is always there; actually up hiil or down.

Have no idea what it could be. I searched the Haynes book through and found nothing. Not even in the trouble shooting section.

Any help or idea is appreciated!
Afraid to drive it and cause more serious problems.

Has anyone else experienced this with thiers?

have you recently put tires on you truck mismatched tires can cause the transfer case to engage the auto 4x4

 

[corkey]

i would look at the u joints for that clunking,

 

[talegatefisher]

Thanks for the reply!

All four tires are a matching set and have been rotated to promote even ware so the problem may be alittle more intence than that.

I have never checked the U-jointsas of yet. Actually will need to look them up to see what i should be looking for. Being that this is all wheel drive with hi/low four wheel option, does it consist of alittle more to check out?

Never ran it off road and everything under it is totally factory. What is a cause of u-joint failure?

 

[mikeh44]

clean your injectors

 

[talegatefisher]

I usually take it in each spring to have the garage clean them and do a over all inspection due to taking alot of trips throughout the summer months. I can call and set the appt. to do it, but how come the injectors wouldnt do it at lower coasting speeds also?

I went out and pryed at the u-joints along with twisting them to check for wear. Tight as a drum, no play there.

Could it be the rear diff or transfer case?

 

[rrgone]

I recommend you remove power fuses #17 and #18 which power the T-case clutch. If your problems goes away with no power to the 4X4 system than at least you know what to start troubleshooting. Let us know what you find out.

edit: I see the OP has an '02. You should know that there are several lengthy threads in here about dead 4X4 control modules in 2002s. Some people reported their module died when the battery died or was disconnected. If your module is still OK you do run some risk to it by pulling the power fuses. On the other hand, if it is still OK it was probably not from the defective batch and will probably survive a loss of power. If your T-case clutch is slamming in and out of 4WD while you are driving on dry roads you can do real damage to the T-case. If it were mine I would pull the fuses to see if that is it.

 

[talegatefisher]

Wow that sounds dangerous. I have to be at 65mph inorer to see if this will work or not work. How much punishment will it take to do any damage. I dont want to cause more problems trying to solve another. What does the power do that I would have to disconnect?

 

[rrgone]

Sorry, I should have just started over with my last post. It was not very well written. Lets try again.

Your A4WD system gets power thru fuses 17 and 18 in the Battery J-Box. Without power the 4X4 Control Module can't activate the electromagnetic clutch in the transfer case. It does sound to me like your 4WD system is engaging and disengaging rapidly while you are coasting at fairly high speed. That's not good. As I pointed out in the edit to my post above, some 4X4CMs in the 2002s were defective and had to be replaced with updated modules. They run about $150-$200 from online sellers, and are an easy DIY R&R.

You really need to find out if it is your 4X4 system kicking in and out for some reason. Once you know if that is it you can start looking for the cause. Could be mismatched tires as was mentioned, could be a faulty sensor, could be the CM is failing, could be you will need to do the brown wire mod... Once you know for sure if it is your 4X4 system, post back up and folks here will try to help. Good luck.

 

[F1EA]

Simmilar issue

I have a '03 4WD and i am experiencing a very similar problem.

sed to have 1 mismatched tire and when coasting (letting go of the accel) to slow down I would feel this pulling/chugging. I didnt know what it was, but reading through here, i got the idea of checking for tire diameters... I bought a brand new set of tires and this particular chugging/pulling went away.

However... right now with the brand new tires, i get a very similar problem ONLY when accelerating. It seems to be more closely related to RPMs, as it happens only between 1,000 - 1,800 RPM. If i gun it, the transmission shifts, the revs go up and the chugging completely dissapears. Also, if its chugging and i let go the accel, the pulling stops.

When keeping a somewhat constant speed, after the transmission shifts and the revs drop back to around 1,200 RPM the chugging starts again even though velocity is basically the same. It kinda feels like the 4wd kicks in, but it also feels as if fuel injection is getting cut on/off.

If anyone has any ideas, pelase help. Im taking it to the shop on thursday but want to be as educated as possible to avoid guessing work.

Note: I am also experiencig a somewhat rough idle (idling at about 800 RPM) and the "Service engine soon" light came on yesterday.

 

[slyfoxexplore]

sound like u joints

 

[F1EA]

sound like u joints

I think the 3rd gens have no u-joints. They have independent suspension.

Edit: it is not a single pull as the shift is completed, its more of a series of pulls whenever the revs get down to, or are at about 1300 RPM, while applying gas. If i give it more gas to bring up the rpms, the chugging/pulling stops (somewhere around 1,800 rpms).

 

[rrgone]

Note: I am also experiencig a somewhat rough idle (idling at about 800 RPM) and the "Service engine soon" light came on yesterday.

Go to AutoZone or Checker and get the trouble codes read for free.

 

[IZwack]

talegatefisher :

90% sure its your rear pinion -- its like the #1 clunk producing thing in the 02 and 03s. The clunk is when the pinion is "free" -- when no torque is being applied to it and it is allowed to wobble around in the housing. Disconnect the rear driveshaft and check for play on the input flange/yoke of the rear differential.

 

[4x4xbrian.com]

I had the shift High/low splines fail in the transfer case, they are tapered for engagement so they can work fine foreward but when you coast or reverse they can jump. Some transfer cases are different so I dont know if yours is the same as mine was.

So Just for kicks try backing up a steep hill or just holding the brakes and gas while in reverse

 

[shadowless127]

I have a '03 4WD and i am experiencing a very similar problem.

sed to have 1 mismatched tire and when coasting (letting go of the accel) to slow down I would feel this pulling/chugging. I didnt know what it was, but reading through here, i got the idea of checking for tire diameters... I bought a brand new set of tires and this particular chugging/pulling went away.

However... right now with the brand new tires, i get a very similar problem ONLY when accelerating. It seems to be more closely related to RPMs, as it happens only between 1,000 - 1,800 RPM. If i gun it, the transmission shifts, the revs go up and the chugging completely dissapears. Also, if its chugging and i let go the accel, the pulling stops.

When keeping a somewhat constant speed, after the transmission shifts and the revs drop back to around 1,200 RPM the chugging starts again even though velocity is basically the same. It kinda feels like the 4wd kicks in, but it also feels as if fuel injection is getting cut on/off.

If anyone has any ideas, pelase help. Im taking it to the shop on thursday but want to be as educated as possible to avoid guessing work.

Note: I am also experiencig a somewhat rough idle (idling at about 800 RPM) and the "Service engine soon" light came on yesterday.

check your IAC, PCV. Also when was the last time you changed your fuel filter & air filter.

talegatefisher :

90% sure its your rear pinion -- its like the #1 clunk producing thing in the 02 and 03s. The clunk is when the pinion is "free" -- when no torque is being applied to it and it is allowed to wobble around in the housing. Disconnect the rear driveshaft and check for play on the input flange/yoke of the rear differential.

The rear pinion is more of a whine then a clunk and occurs regardless of RPM range. A bad pinion doesn't give you a tug of a rope feeling either. The main thing with the ring and pinion is it's just friggin annoying.

Deff sounds like your 4wd is engaging and then disengaging.

 

[talegatefisher]

I appreciate everyone stepping in to help! This trucks to young to act this old.

Ill try just about anything to find it anymore. So removing these fuses 17 and 18 and taking it for a test drive will help give a better idea of what could be going on. How far of driving without the fuses do you think would be to far?

Im also gonna try the reverse up hill to see if this will show me something.

This 02 explorer has been a nightmare of repairs.
Sad part is; It only has 80,000 miles, never been off road and well maintained.

Soon as I get a chance to try out these test, Ill post back with the results!

Thanks Again!!

 

[F1EA]

check your IAC, PCV. Also when was the last time you changed your fuel filter & air filter.

The rear pinion is more of a whine then a clunk and occurs regardless of RPM range. A bad pinion doesn't give you a tug of a rope feeling either. The main thing with the ring and pinion is it's just friggin annoying.

Thanks. I changed my air and oil filter about 3,000 mi ago. But havent changed my fuel filter, so i'm goint tomorrow to get the "Service Engine Soon" read, check the spark plugs, IAC/PCV and change the fuel filter. For sure, my chugging/pulling thing is like intermittent tugs of rope. Above 2,000 rpm it never pulls and everyhting is quiet, but when giving it moderate or hard gas it will chug/pull until either the revs reach 2,000 or the tranny downshifts (rising rpms)...

My diff whines (dont know if its the front or rear)... only while applying gas mainly between 30-40 MPH regardless of the rpms... but i dont plan on fixing that until it breaks into pieces. Its too much money to throw away on a part that will fail again, together with the rest of the self-destructing drivetrain...

 

[F1EA]

Problem solved

Before getting to work with it, got the codes read. The errors were: P0300 (random misfire), P0301 (misfire cyl 1) and P0316 (refer to technical documents).

Decided to clean injectors, changed spark plugs (checked the wires and ign. coil but they were ok, the plugs were not all that bad but changed them anyway), changed fuel filter and while at it changed the oil which already had about 4,000 miles. All parts were Motorcraft, and oil was Mobil synth. Total spent as around US$285 incl. labor. And removing the old fuel filter was a true nightmare.

After all... the problems completely went away. The truck is now idling super smooth, with great response, no chugging/pulling (which was my main concern, as i found it hard to think an engine problem would cause such pulling). So... knock on wood and hope for the best.

Thanks to everyone who helped. I felt really secure as i went into it all...

 

[talegatefisher]

Stll have the same problem. Shifted it in neutral to see if it would stop but no luck. There is no vibration with the driveshaft at all even at 90mph. Have noted that once it begins to jerk while coasting at 65mph, it will continue to jerk as truck slows down to about stoped and even with brakes applied. Will stop jerking if you get back into the gas until your foot lifts off the peddle again. Does not clunk when changing between forward and reverse gear so this pretty much rules out the yoke. Does not have the metallic grings as a bad u-joint. can not tell if its in the transfer case or the rear diff. Changed through 4low, 4high and back to 4all and everything switched well.

Could there be something we may be missing here?