Hi everyone. Sorry for the blunt nature of my post, but I'm 800 miles from home and my 1999 expedition(125K, 5.4L, 4x4) is giving me fits and becoming undriveable.
1. On the way here, there was an occasional clunk/shudder while driving at highway speeds. By the end of the 800 mile journey, the front drivers tire apparently developed a leak and dropped down to 16 psi, meanwhile the rear passenger tire went bald.
2.Bought a new tire to replace bald one, drove 150 miles with no problems. On the return trip, the vehicle developed a horrific hot-grease odor. It then groaned to a stop in a service area. Let it cool for an hour, drove okay.
So, has anyone experienced this before? I'm wondering , do I need all 4 tires to be exactly the same (brand,tread,etc) or just tread depth? I'm guessing having one new tire (14/32's) and 3 older ones (5/32's) probably worsened the situation. Is that triggering the a4wd to kick in?
Have read some info regarding the GEM module and its role in these problems, could that be it?
Or , am I experiencing the beginning of some catastrophic failure, such as with the transfer case? And is there any way to defeat the A4wd system and just maintain the vehicle in 2wd? Honestly, I'm leery of driving this back 800 miles on interstate until I can get it figured out.
Any help would be greatly appreciated, especially as I have little experience with AWD/4WD systems. I really need some help from those familiar with this particular vehicle and drivetrain combination.
1. On the way here, there was an occasional clunk/shudder while driving at highway speeds. By the end of the 800 mile journey, the front drivers tire apparently developed a leak and dropped down to 16 psi, meanwhile the rear passenger tire went bald.
2.Bought a new tire to replace bald one, drove 150 miles with no problems. On the return trip, the vehicle developed a horrific hot-grease odor. It then groaned to a stop in a service area. Let it cool for an hour, drove okay.
So, has anyone experienced this before? I'm wondering , do I need all 4 tires to be exactly the same (brand,tread,etc) or just tread depth? I'm guessing having one new tire (14/32's) and 3 older ones (5/32's) probably worsened the situation. Is that triggering the a4wd to kick in?
Have read some info regarding the GEM module and its role in these problems, could that be it?
Or , am I experiencing the beginning of some catastrophic failure, such as with the transfer case? And is there any way to defeat the A4wd system and just maintain the vehicle in 2wd? Honestly, I'm leery of driving this back 800 miles on interstate until I can get it figured out.
Any help would be greatly appreciated, especially as I have little experience with AWD/4WD systems. I really need some help from those familiar with this particular vehicle and drivetrain combination.
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