clunking, binding, bucking......

[Roadkill Savior]

About 2 years ago my front drivers side really started ratcheting, bucking and binding so bad that the Explorer had to be parked. It was very noticeable you could hear it from 100 feet away and if I tried turning at slow speed the front end would rise up and back down and clunk badly, it also needed extra pedal to move when turning....felt like something was going to break.

After a couple days I unplugged the harness at the transfer case and the problem went away. Now it's time to do something about it....

It's a 99. Could it be the hub, cv joint, bearing? Or am I screwed and it's the transfer case? Could it be a sensor somewhere? Also I get the flashing 4wd lights every so often like something is telling it the whels are slipping even though they aren't.

Please help.

 

[IZwack]

This is a common issue -- its the transfer case, its stuck in 4wd or engaging 4wd.

 

[hworksinc]

Sounds like it's engaging 4WD when it shouldn't - this is usually caused by a faulty wheel speed sensor. Search around the forum and you'll find a few threads about it. Alternatively, you could do the brown wire mod and disable Auto 4WD entirely - that way you only have 4WD when you want it (cheap fix). Since you've been driving it for 2 years since you disconnected the TC, I doubt there was any collateral damage.

 

[Roadkill Savior]

OK so I have 2 problems?

1. I need to replace the transfer case to stop the binding problem

2. I need to replace the sensor to make it stop going into 4 wheel drive.

Correct?

I really need to fix this so I can sell it and get a van for the wife, now that we have 4 kids the Explorer has become too small.

It only had 73,000 miles when this started, is it common for transfer cases to fail so soon. It now has 88,000 miles.

 

[Roadkill Savior]

I was originally thinking cv joint but it doesn't do it in 2 wheel drive.....why?

 

[NHale623]

Sounds like it's engaging 4WD when it shouldn't - this is usually caused by a faulty wheel speed sensor.

I don't think the wheel speed sensors have anything to do with AWD or 4WD. I think their only purpose is for ABS.

I think your problem is in your transfer case.

 

[Roadkill Savior]

Thanks guys........

What model transfer case should I be looking for?

Or should I split the cases and repair this one?

I am pretty handy with wrenches I have rebuilt a few 4 cylinder air cooled motors and I am pretty confident in my skills....just don't know which way is going to be cheaper in the end. A lot of $40 parts can add up pretty quick.....I've seen transfer cases on the bay for around $200. Remember I just need to have it running so I can trade it in at a car dealer.

Oh and with the economy the way it is I really don't have much to spend.

 

[410Fortune]

just go trade it in and let them fix it?


lets starts with:

what engine does your 99 explorer have in it?

 

[Roadkill Savior]

I think I can negotiate better if it's working.


SOHC 4.0

 

[IZwack]

Okay the problem is electrical -- which is obvious because when you unplugged the transfer case connector, the symptoms went away. So, having said that, the 4HI/4LO lights might be blinking which will give you hints as to what's going on. If the 4HI/4LO isnt blinkding, then its probably a speed sensor.

The speed sensors (at the transfer case) has everything to do with 4WD because they sense when a driveshaft is spinning slower than the other one which means one of the axles is not getting the grip it needs.

The good news is that this is not (i repeat NOT) a mechanical problem and therefore the costs shouldnt be too high, and obviously you wont have to replace or repair the transfer case itself. The bad news is if your 4HI/4LO lights are not blinking, you'll have to test each sensor (of which there are two, one in the front of the transfer case and one in the back) with a multimeter.

 

[Roadkill Savior]

The lights do occasional blink, like a sensor is telling it the the driveshaft is spinning, like you said.

AND

When it was in 4 wheel drive......you can't drive it because it binds up way to bad. Like the front axle or wheel is going to snap.

So what does that tell you?

More than one problem?

I do have a multimeter........ how do I check them?

 

[IZwack]

Well since the lights blink, take it to a Ford dealership (unless you yourself have a code reader than can pull codes from the 4wd system, which are expensive units) and have them pull the codes for the blinking 4HI/4LO. That will tell you which sensor is going wack. Then all you have to do is replace the sensor yourself -- which can sometimes be a challenge as these things do not come out very easily even though it is literally just one bolt that holds them down.

 

[Roadkill Savior]

Dealer ship = too much money. Can't I just check them myself?

 

[IZwack]

Dealer ship = too much money. Can't I just check them myself?

I dont know the OHM values for the sensors so I can't tell you that they should be between x.. and YYY ohms.

But do a continuity test on the sensors and see if one comes out as completely dead. Then it would be completely obvious which one needs to be replaced.

For fun, these sensors are field effects (solid state) and if you disconnect the driveshafts and put the transfer case in neutral (by removing the shift motor and turning the shift rod manually), then you can spin the output shafts (to which the driveshafts connect to) by hand and you should get a rapid and somewhat sinusoidal voltage output from the associated sensor. But most common multimeters will probably just display a very erratic voltage reading.

 

[Roadkill Savior]

Where can I buy the sensors? How much are they?

I just did a search and came up with nothing.

 

[IZwack]

Dunno how much they are but you can get them from Mr. Torrie McPhail at:
http://www.fastpartsnetwork.com/

Mr. McPhail's user name on the forum is tmcphail
http://www.explorerforum.com/forums//member.php?u=4536

 

[Roadkill Savior]

Thanks for your help....I just sent him a private message.

What about the binding clunking problem?

 

[IZwack]

What about the binding clunking problem?

These sensors is what is causing the binding and clunking.

See when a vehicle is in 4wd (or is engaging 4wd when its not supposed to), then the transfer case is 'locked' and that means both driveshafts must be spinning at the same RPM. But of course this is not possible when the vehicle is turning because most of the time during a turn, no two wheels will ever follow the same arc. This causes a difference in the RPMs between the two driveshafts and the drivetrain binds. Normally you wouldnt experience this bind because normally you would only engage 4wd when the vehicle is off road and in off road conditions, the wheels are able to slip on the surface its on which relieves the drivetrain bind. But on pavement when the 4wd is engaged, the wheels can not slip and the result is the engine sounds like its about to die and the transfer case's internals are stressed immensely. If you do this enough time, the transfer case's chain is stretched more and more (to a point where it could break) and the transfer case's main shaft and input bearing lobes are elongated and will be more oval than a true circle (which we've seen a few instances of on the forum).

 

[Roadkill Savior]

So your saying these actually lock the front like a locker when in 4 wheel drive? I thought these were limited slip? Or are you saying it's malfunction is causing it lock? or do these really lock? I'm confused.

I am familiar with the binding that occurs from that.....I've owned a few big 4x4's in my life (when I was younger) and I use to do a lot of wheeling I had a 78 F250 with Dana 60's front and rear, 4.10 gears 38" tires on 16.5 rims, Edelbrock intake, Carter 4bbl, Headers, duals, C6 W/stall converter, NP 205 TC that thing was a beast......2 gas tanks........and it needed them since it averaged about 8 ft to the gallon. I later had a tricked out Eddie Bauer Bronco. That was great for turning around on tight trails and getting through ditches.

 

[IZwack]

Neh I never said anything about a locked front axle. What I said was a locked transfer case -- in other words, a transfer case thats in 4wd.