Strange Vibration Going Up Hills Slowly, and No Low Gear

[Foresthill]

2000 XLT - 4WD Auto -When I start up from a stop sign, going up a slight grade, and not trying to get up to speed quickly, I get a rythmic thumping, like hitting a regularly spaced bump in the road. Seems to happen at about 2000 RPM, can't tell if it is in low or second, and will keep doing it as long as I don't accelerate. Feels kind of like a flat spot on the tire(s), seems to be coming from the front end. If the window is open, I can occasionaly hear a rubbing sound as each bump is encountered. Last year I had a high pitched squeak at low speeds, and the dealer replace front seals under warranty.

Also, I have low gear when the car is cold, but after about a mile of driving, I then have absolutely no low gear, it does not downshift at all from second. just freewheels if I try to use engine braking going downhill. I live in the mountains and frequently need engine braking.

I just found a TSB about the low gear problem and will take it to the dealer next week. Is it possible that the two situations are related?

 

[slow-demon]

The rythmic thumping you hear is because of the 4x4 auto. The computer is pulsing the clutch in the transfer case getting ready to fully engage it if the need arises. Not a real problem. The Ford fix is a reprogram of the gem module, which controls the 4x4. I thinks its a tsb. I fixed a few like that.

 

[TPLYNCH]

You also need to have the OD off to get engine braking in 1 too. Discovered this driving the mts of Vermont last week.....