Front diff rumble ?? | Ford Explorer Forums - Serious Explorations

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Front diff rumble ??

nickburt

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City, State
Wallasey, Wirral. UK
Year, Model & Trim Level
1998 Explorer
First post folks - what a great forum you have here, been lurking for a while and learning a few things about the Exploder, sorry, Explorer !!!

Anyway, would be good to get some help and advice on a problem I have please.

'98 UK spec 4.0 V6 auto - it's a truck I look after for a disabled friend of mine.

Has a rumble from the front end, which I originally thought might be a wheel bearing, but having checked them both - they're fine. The rumble has only recently started. We don't remember it starting quietly and getting worse, it just seemed to suddenly be there. Starts at a round 20 -25 mph, gets a bit worse up to about 40 and then just levels out in terms of type of noise and volume.

Rumble is there in 4wd auto and 4wd high. Not sure about it in 4wd low as the noise from the engine drowns it out, if it is there, when you get up to enogh speed that you would be able to hear the rumble.

I've just changed the diff oil and that didn't make a difference. Oil was slightly emulsified from a few dunkings while off road. This may have resulted in some damage to the diff gears, but was hoping that fresh oil would help. Eventhough it's emulsified, it still seemed reasonable - no worse than another 4x4 of mine (Mits L200) has often suffered without causing any damage.

I'm still trying to get my head round how the 4wd auto works - is it possible the control system is trying to engage 4wd when it shouldn't and is only partly engaging 4wd. The L200 has a diff actuator that, if the vacuum system is acting up, will try to engage the diff, even though the 4wd shift is still in 2wd, and then gives a rumble fromt he front diff, so I'm wondering i the Explorer is the same or similar.

Transfer box has good condition oil - was changed a couple years ago, but the truck is used so little, I'll bet it's only done about 10,000 miles at the most since.

Your thoughts and advice will be greatly appreciated.
 



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First post folks - what a great forum you have here, been lurking for a while and learning a few things about the Exploder, sorry, Explorer !!!

Anyway, would be good to get some help and advice on a problem I have please.

'98 UK spec 4.0 V6 auto - it's a truck I look after for a disabled friend of mine.

Has a rumble from the front end, which I originally thought might be a wheel bearing, but having checked them both - they're fine. The rumble has only recently started. We don't remember it starting quietly and getting worse, it just seemed to suddenly be there. Starts at a round 20 -25 mph, gets a bit worse up to about 40 and then just levels out in terms of type of noise and volume.

Rumble is there in 4wd auto and 4wd high. Not sure about it in 4wd low as the noise from the engine drowns it out, if it is there, when you get up to enogh speed that you would be able to hear the rumble.

I've just changed the diff oil and that didn't make a difference. Oil was slightly emulsified from a few dunkings while off road. This may have resulted in some damage to the diff gears, but was hoping that fresh oil would help. Eventhough it's emulsified, it still seemed reasonable - no worse than another 4x4 of mine (Mits L200) has often suffered without causing any damage.

I'm still trying to get my head round how the 4wd auto works - is it possible the control system is trying to engage 4wd when it shouldn't and is only partly engaging 4wd. The L200 has a diff actuator that, if the vacuum system is acting up, will try to engage the diff, even though the 4wd shift is still in 2wd, and then gives a rumble fromt he front diff, so I'm wondering i the Explorer is the same or similar.

Transfer box has good condition oil - was changed a couple years ago, but the truck is used so little, I'll bet it's only done about 10,000 miles at the most since.

Your thoughts and advice will be greatly appreciated.

Not knowing exactly what differences exist between UK-built and US-built units project, so, what is an L200?

2nd. gen. explorers used a front drive connect/disconnect means, vacuum controlled, which allowed disconnecting of the front driveshaft from the front axle. If the vehicle has "4WD AUTO", it has a computer-controlled Electronic clutch (read that an electromagnet type clutch) in the transfer case, which engages based upon detected wheel spin between front and rear.

When exactly is the rumble noticed? imp
 






Many thanks for the reply imp.

The rumble starts quietly from about 20 mph, and gets louder with road speed.
Doesn't seem to make any difference if going round corners. It's there all the time and is road speed related, not engine speed. Definitely coming from the front somewhere, you can even feel it very slightly through the floor pan.

An L200 :

Mine:
IMG_4230.jpg


The Mrs'
IMG_4790.jpg
 






And here's the Explorer:

IMG_4994.jpg
 






Front pinion bearing? Drop the front shaft and check for looseness

Bill
 






Front pinion bearing? Drop the front shaft and check for looseness

Bill

Thanks for the suggestion Bill, tried that, seems OK.

Bit of an update, the tone of the noise changes when going into left hand bends, but not right hand ones. Checked the wheel bearings again, they both feel fine.
 






Thanks for the suggestion Bill, tried that, seems OK.

Bit of an update, the tone of the noise changes when going into left hand bends, but not right hand ones. Checked the wheel bearings again, they both feel fine.

as they are hub units the proceduer for checking is different, had same problem and changed both hubs and it fixed it, had done over 200k ks so if it didnt fix the noise all was not lost
 






If it changes with direction, suspect outer front axle bearings. Especially if the seals where the half shafts meet the housing are wet.

Bill
 






Thaks for the advice guys, I'll check them out again.
 






Front drive (propeller) shaft.
 






Failed Wheel Bearing

The image shows the outer race of my wheel bearing, galled, noisy, but still operating after several thousands of miles of noise. Definitely a rumbling sound, but also had a whine component. The bearings are serviced as a mounted pair, through the center of which the driving axle shaft passes. I had to tear the bearing apart to get inside to view the damage.

Turning the assembly while still mounted in the vehicle produced no discernible noise or unusual (rough) feel. I had used my stethoscope to listen closely to the center section (differential), as well as the two wheel bearing (outer) areas, while running in gear up on jackstands. This method most definitely eliminated the center section, as well as the right-hand side wheel bearing. Thus, I ordered new bearings for both sides, replaced them, and tore apart the offending bearing. I could not believe a failed bearing, producing the level of noise it finally reached, could not be felt by hand-turning the bearing! Yet, there it was.

The damage is centered across the face of the raceway, but not damaged clear across it. Thus, the rollers were still able to carry the load without disintegrating (which, of course, they eventually would have), but did produce noise as the loaded parts ran across each other. imp

wheel_10.jpg
 






I must admit, as soon as I did notice a slight difference when turning, I suspected wheel bearing again. Maybe time to bite the bullet and fit a pair of new ones.
 






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