4x4 issues.

[Relvie]

Hi guys having another problem with this explorer. Its a 91 with manual locking hubs. I just recently got the shift motor working so now the 4x4 is engaging but when I try to drive it seems like the front wheels are trying to drag. I get a loud metallic clinking noise aswell doesn't seem like the front is pulling at all and I have to give it a good bit of gas to get it moving. Works fine in 2wd but 4wd high or low I get the problems. Anyone know what it may be? I'm new to 4x4 so I'm lost with it.

 

[arco777]

Doesn't sound right at all!

 

[MrShorty]

It sounds to me like tension in the drivetrain. Is this test being done on pavement while turning? Is it possible the front and rear tires are different sizes? Are you certain the front and rear differentials have the same gears in them?

 

[Relvie]

The tires are different sizes. 225 in front 255 in the back. The diff's are just as it left the factory so I would assume it has the right gears. The test was on pavement and in sand. The front diff started to leak fluid on the drivers side so I only tried it once.

 

[MrShorty]

The tires are different sizes. 225 in front 255 in the back.

Well that's probably the problem. There's not enough information to determine the difference in tire diameter, but that difference is probably significant and the likely cause of what you are seeing.

Why, you ask? In a traditional part time 4wd system (like ours), the driveshafts are locked together at the transfer case, so they have to spin at the same speed. With different size tires, they can't spin at the same speed, which results in the symptoms you describe.

 

[arco777]

The tires are different sizes. 225 in front 255 in the back. The diff's are just as it left the factory so I would assume it has the right gears. The test was on pavement and in sand. The front diff started to leak fluid on the drivers side so I only tried it once.

Agreed with MrShorty - with a 4WD system like ours, you can't have different diameter wheels front to back. Even an inch can make a difference. That would cause a real problem.

In mud and snow you could get away with a difference like that but it's still not ideal. On pavement that would be hell on your driveline.

 

[Relvie]

Ok the only reason it has different sizes is because I couldn't find the right ones and the 4x4 didn't work so I figured there wouldn't be an issue. Is it fine to use with 2wd and these tires until I get the right ones ? The height and profile are are the same only the width are different.

 

[MrShorty]

On a traditional part time 4wd system, the front end is completely disengaged in 2H, so you'll be fine running in 2wd.

 

[Relvie]

Thanks for your help again.