control-trac issues

[explorerkathy]

First post so please no trashing, bashing, or flames. thx

Our 2002 Eddie Bauer 4.o sohc explorer has the "control-trac" system. At light to mid throttle application during acceleration, everything is fine. During harder acceleration, a slip or thumping can be felt. I have tried pushing the "4X4 high" button when it is doing this and it goes away. It feels like the front end is trying to engage but I'm on dry pavement with no slip. Is there a "slip sensor" or something that could be going bad or is it the t-case? Truck is an automatic with approx 55,000 miles on it. The feeling is exactly like when it is engaging 4x4 on snow or ice. Any help would be appreciated.

 

[Skibug]

Are all your tires the same size and inflated to the same pressures? It has been a problem before when your tires are not all the same size or inflated at different PSI's that the system will kick in because the sensors will see different speeds at each wheel.

 

[IAmTodd]

There have been several issues with the Control Trac computers. Normally the system kicks in under hard acceleration, that was how it was programmed, but you should not feel the thunk of it doing so. I'd stop by a dealer and see what they have to say.

 

[00XLS]

During the recent snow fall here in PA I notice something with mine as well. 00, XLS, when going around a corner, if I would purposely kick out the back end it didn't seem that the 4x4 would engage. It engaged fine when the switch was in 4HI, is everything functioning fine or what? Opinions?

 

[jayhawkexplorer]

Remember that control trac (when set in auto) is sending 96% of the power to the rear wheels. So it takes a sec or two for the front wheels to get their power. But I've always been able to easily correct a tail end slide with mine using the auto 4WD, that's one of the things I love about it. So I don't quite know if your truck is working right or not.

 

[00XLS]

hmmm I'll give it a shot on my way to work tomorrow, when i go up a steep driveway thats covered its usually no problem but the fishtailing had me wondering

 

[explorerkathy]

Thanks,

Tires are all new (Michellins). I will check the pressure though. Isn't the pressure different from front to back? Or should I set them all to the same? Thanks everyone for the quick response!

Also, the thump is speed related. IE.: it thumps faster as you accelerate.

 

[00XLS]

Thump def. sounds tire related, I'd go over the whole driveline as well. I always set my tires to the same pressure, front to back.

 

[explorerkathy]

please keep in mind, the thumping ONLY happens when under half to full throttle. Not when accelerating at normal to moderate rates.

 

[jimbo74]

almost sounds liek an out of round driveshaft or out of balance

 

[IAmTodd]

You are to have different pressures. Atleast ours states 30psi in the front, 35psi in the rear.