2002 Explorer 4x4 4.0 auto, 100,000 miles

[John Ewers]

My wife was complaining about a "missing" but when I drove the car after 30 or so miles going uphill at 30 mph under moderate power it felt like I was hitting expansion joints on the freeway- not tires, not all the time- a mild "klunk" or "slip" at a steady speed- We are going on a 400 mile trip in two weeks and don't want a breakdown while we are gone. Is this something that will cause a major breakdown in the middle of our trip or can we make it through before a major service?
We haven't had a transmission service since getting the car (100,000+ interval)- Could this relieve us of this problem?
Need an answer soon or have to rent a car for our vacation!

Thanks!

John

 

[BrooklynBay]

Welcome to this forum! Is it like a shift flare or more like a bad U joint or noisy slip yoke?

 

[rrgone]

Hi John, welcome aboard. I recall a few posts describing nearly the same condition you have. The good news is it doesn't sound like tranny to me. This is from memory, but I think the causes were:

1. Bad wheel bearing, or
2. Different size tires, or
3. Bad 4X4 Control Module.

The wheel bearings are notorious for failure on the Gen 3s. There are tons of good posts here about this fact. Do a little searching and you will be see.

If you have one or two tires of different size than the others, through replacing one or two or uneven wear, your 4X4 Control Module can sense 'slip' and pulse the 4X4 system. Have you recently replaced one or two tires?

The 4X4 Control Module is also notorious for failing in the 2002s. Usually they just quit working but sometimes they are dangerous and try to lock in 4WD on dry pavement. Yours could be trying to do that. You could rule this out by disconnecting the 4X4CM and see if it stops or not. This would rule out #2 also if it didn't stop.

Good luck - let us know what you find out.

ps: Your tranny is way overdue for service. Likely your differentials and trans case too. The service intervals listed in the Owners Manual are nuts. Get 'em serviced at a reputable shop, not a Quicky Lube type place.

 

[Thelt]

Could be an issue with your spark plugs or wires.

 

[rizzjc]

Could be an issue with your spark plugs or wires.

I didn't believe this one ... until it threw a code, and I lost all power. Now I believe. But this was a mild "miss" type feeling, so not sure that's the same thing you are feeling.