My 00 F150 Has A Nasty Vibration Between 40-45mph Accelerating And Decelerating. I Just Replaced The Driver Side Lower Ball Joint And Am Planning To Do The Passenger Side Soon. After Replacing The Ball Joint The Shake Went Away For A Little While But Is Back Again. Some People I Talk To Say Its My Tires (305 Maxus Mudders). The Truck Has 82,000 Miles. I Planning On Putting A Steering Stabilizer On The Truck And Replacing Front Shocks. Does Any One Have Any Ideas As To What This Shaking Could Be So I Can Fix It Before I Damage These New Parts? Thanks In Advance For You're Help
Cliff

 

You might want to do a search for torque converter shutter. Hard to tell from your post if that's what you have. If it is converter shutter, changing (or flushing) trans fluid will usually cure it.

 

put the front tires in the back and the back tires in the front, see if there is a difference. you could have tires out of balance or excessive road force variation(a hard spot).
I have seen a lot of those nobby tires become "cupped" if not rotated 6k on the dot. to check for this slid your hand flat over the tread, do the inside center and outside, the outside is where they usually cup, you may feel consistent ups and downs every 3-4 inches- if so tire is junk or just deal with it and put it in the back. Ive seen a few with hard spots, which even if its balanced it wont feel like it.

 

I Am At 8000 Miles Since Last Rotation But Have Been Good About Getting It Done Every 6k Since Buying The Tires(after Rotation Less Of A Shake But Still There). Will Check For Hard Spots And Also About Due For A Tranny Flush So I Will Do That Also---thanks For The Help, You Really Cant Beat All The Experience And Knowlegde That The Members Of This Forum Have!! Thanks Again