I'm having this problem with my truck that makes it feel like im getting rear ended when I take off from a complete stop. If I give it a little gas and start rolling and then give it a little more gas to speed up, it feels almost like a really hard shift. It's not shifting at this low of a speed though. It also produces this feeling when I get on the gas pretty good going about 40 and then let off the pedal.

After reading some previous posts about similar issues I decided to change the spark plugs, drain the tranny and torque converter, and change the rear axle fluid. No luck yet. I also had a mechanic do an inspection and he found no problem with the rear axle clutches or bushings.

He said it may be worn spider gears in the rear axle. My truck is also in the mud quite a bit. He said there is quite a bit of mud in between the leaf springs which may be contributing to the problem. Could there be so much mud that the springs are moving back and forth excessively? Would worn spider gears produce this feel? I have read posts about the 1-2 and 2-3 shift springs but this is occuring at very low speeds primarily (approx. 5 mph).

Anybody know what might be causing this problem?

Thanks.

1999 F150 4x4 5.4 V8 Ex Cab Short Bed Non-Posi rear

 

If your truck has some miles on it, you may being hearing play being taken up in one or more of the following components: motor or trans. mounts, output shaft of the transfer case, U-joints, ring and pinion, spider gears, axle splines, loose lug nuts, axle tube U-bolts, leaf spring bushings and if it has a rear sway bar, link pins or bar mounts. Post the fix when you find it (please).

SL