97' Explorer XLT AWD 4.0L. Please help!

[Rastus]

Hi there, I'm new to these forums.

To start off, like the title says, I'm working on a 97' XLT Explorer for somebody. It's a 4.0L, AWD, with a 5 speed auto.

The problem is that it clunks and causes a commotion sometimes, and I can replicate the problem if I drive at higher speeds. It doesn't only do it at high speed though, sometimes it'll do it going 55 or so. It, however, has not done it to me below 50MPH. It feels like someone is turning the key off for a split second and then turning it back on, then it'll take the slack back out of the driveline(which makes it feel like someones beating on the floorboards) and keep going.
I've looked around and I haven't read of anyone having these problems, but from what I've seen I'd like to say it's one/both of the t-case sensors. The transmision shifts well and the motor is smooth and seems to have good power for what it is. I've been trying to employ the KISS method of solving this, but I can't nail it down.

So far I've:
-Taken the speed sensors out of the t-case, cleaned them and put new fluid in.
-Greased slip yoke due to clunk when put into drive, but may need new u-joints because clunk is still there when I put it in drive.
-Made sure all the tires match and their pressures are the same.
-Seafoam'd motor, checked air filter, and added fuel system cleaner. I'll be putting new plugs and wires on, and changing the oil+filter tomorrow.


Does anyone have any ideas?

Thanks.

 

[Turdle]

Check the throttle position sensor

Look at the voltage rise carefully for a spike, or dead spot

 

[Dan Whitaker]

Check the front drive shaft. Ford used a CV joint where it bolts to the t-case.

I had been chasing a what started as a clunking noise in May to what has became a full out vibrating, shaking, popping, rattling SOB. It ended up being the CV joint is all but gone.

 

[Rastus]

Well, I tried what you guys suggested.

The TPS tested fine, no spikes or drops, just steady increase. I looked at the front driveshaft, and besides some play in the transfercase between the gears it was solid. No up/down or side to side play.

I forgot to add that the vehicle has about 105K miles on it, which I don't believe to be alot these days. It seems to have had good maintenace. *shrugs*


Thanks for the suggestions, anything you guys can come up with would be a great help. If you need more info or need to ask something, let me know.

 

[Rastus]

I've got an update.


I've noticed it has a very audible clunk when put into drive, sounds alot like a really worn out u-joint. Also, you can feel a vibration in the wheel at about 55. When you stop and just barely get rolling again you can hear a clunking noise that gets faster until about 5 mph.

All of these things makes me want to say u-joint problem, but I checked them already and they seemed fine? This is driving me crazy

Should I take the front shaft out and then drive it to see if it gets better?

 

[Dan Whitaker]

Yes. You can't always tell if a u-joint is bad by trying to twist the drive shaft.

 

[Rastus]

Well, I have the front shaft out right now, and it's A-OK. No play in the front u-joint and the CV is in good shape.
I was looking around somemore and checking things, and I noticed that there's a lot of play in the transfer case it seems. I had the truck in 4high (while running) with the front on stands with the selector in P and N, and there is still alot of play between the gears it seems like. Is this transfer case supposed to have this much play due to how it's designed?

I think I'll drive it tomorrow without the front driveshaft and see how it does, and I'll post back.

Also, when I'm casually driving through town it seems like it lurches alittle(not bad by any means, but you can tell), like the front and rear are fighting each other and somethings changing the speed/torque to each set of wheels. My G/F can tell it's doing it too, so I'm not imagining it. Is this part of the AWD?


Sorry I'm asking so many questions, but I'm pretty young at 18. Gotta learn somehow

 

[ARTURPOLAND]

what do you mean by lot of play ? How many degrees. some play is normal. check if there is a play side to side and up & down not only at the front of the t-case but also at the rear where driveshaft enters the t-case. I have similar problem and intend to change T case bearings but also am trying to obtain any commitment that it is due to the worn bearings.

 

[Rastus]

I'd say it's every bit of 30-45 degrees rotation.

I'll check the bearings for play also.

 

[dynamite196]

Sounds a lot like a torque converter to me, did he do any heavy towing with the vehicle?

 

[Rastus]

To be honest, I don't really know if it was used for much towing. The current owner bought it used, and didn't really have much on the history of the vehicle. It doesn't have a hitch, and the bumper doesn't look like it has had a ball mounted on it before.

I still need to check the bearings, because it's currently raining and crappy out right now. I'll check them tomorrow while I'm putting the front shaft back in. I drove it today without the front driveshaft and things didn't improve, it may have gotten alittle worse.


I thought it might be OD problems in the transmission at first also, but it does it regardless of whether the converter is locked in OD or not. With the OD off via the column selector, it has problems at the same MPH as it does in OD. The fluid looks good and doesn't smell burnt/bad.

:frustrate


Are all Fords this troublesome? :

 

[ARTURPOLAND]

30-45 rotational play is a lot to me. My has some 15 degrees no more. Check side to side and up and down play at the rear t case. try also to differentiate slightly the pressure between front and rear tires. I did it once and fight between axles stopped (in my case I pumped front 0.2 bar more than rear).

 

[lanmanager]

My 98 5.0 awd is doing the same thing. It comes and goes. I'm pretty sure it is that CV joing on the main front driveshaft right next to the transfer case that Dan Whitaker mentioned. And I'm sure that's your problem too. Thing is you can't just look at that joint and pronounce it good/bad. It has to be under a pretty good load to make the noise it makes. Those AWD transfercases are a chain and 2 viscious clutches. I don't think that would make noise that comes and goes. Anybody have any other ideas? This noise sounds just like c/v noise execpt it gets worse during accel/braking. And its 4 times the wheel speed ;-).