So my parents 2001 supercrew shakes under acceleration when turning and gets worse as the truck warms up.this has been going for about 2 months. It's not an unbearable shake but well noticed

My first thought was u-joints but a while ago the shop said they were fine
a bad front wheel bearing was just replaced

Truck is 4x4, 5.4 has 154,xxx miles
and is all stock

Any thoughts on the problem, u joints?, axles? bearings?

 

If it has a limited slip axle, it may be clutch pack chatter. Change the lube (75W140 full synthetic) and add a bottle of friction modifier.

 

I doubt very seriously whether or not heating up would effect this or not, but what kind of shape are the inner tie rods in? I had one that was bad that made my steering wheel shake around a bit. Had no idea what it was till I got under there and noticed the rubber boot on the end about to fall off

 

alxe lube was changed last spring

don't think its a tierod cause it's not in the wheel it's the truck

could it be a bearing in the rearend

 

Broken belt in a tire will do that too

Frank

 

sounds reasonable but would that account for it getting worse as it warms up

 

The axle lube may have been changed last spring, but was it changed with 75w140 full synthetic and friction modifier?

 

Not sure