lately i've been having a pretty steady vibration in my 97 150 xlt 4x4 (auto transmission, 4.6 engine) it only happens when i'm driving keeping a constant speed anywhere between 35 to 45 mph. once i get to a speed higher, it goes away. also, it feels like there is a pretty good jolt when it shifts up (only at certain times) anyone have any clue on what it could be? this is my first time posting on here, but i have been searching for this problem for over 2 months now on here and have come up empty. replaced spark plugs and wires, tie rod ends, rear u-joint, all things that i found on here that may have been the problem, but none have helped. anyone think of anything else it could be?

 

Tire balance/out of round?

 

tires are all in balance

 

possibly check the driveshaft for a missing weight, or put of balance?

just an idea.. most likely wrong, but its a shot

Jon

 

ill check the drive shaft thing out

does anyone think it is something in the rear end ? transmission? or are they all something that i can go ahead and rule out? i just want to see if anyone else out there has had any similar problems and what it was to fix it.. its been doing this for over 3 months now and any place i've taken it to claims they don't feel it happening

 

heres my most annoying experience. truck would bounce at around 45 mph, so bad it was visible in my mirror watching the bed. so i thought it was simple as rotating the tires to see if its moved. nothing changed, went to rotate again and the right front was stuck to the hub. i gave it a kick figuring it'll jar it off for me, except i noticed the tire shook like the tie rods were going. chased it down to be the idler arm mounting bolts were loose.