death wobble

I had a ride in a truck today an 06 f 350 4x4 lifted like 4-6 inches 40-50 mph hit rough patch in the rode and it started it is probably one of the scariest things ive been through in a vehicle was told this is a caster issue googled it found lots of talk about it but really no answers im sure you have heard of it and can shed some light on this thanks

death wobble is caused by bad balljoints or tie-rod ends .....and the track bar not properly torque... it can be a combination of those things

Those trucks are notorious for that problem. The double shock steering kit helps but like you have already observed...none of the lift kit companies will take the blame.

i got the caster deal from a lift company tech line i have no clue

im a front end tech at a ford dealer the most common problem with the death wobble ecspecially on lift trucks is the drag link from the pitman arm to the pass spindle.I have also talk to ford hotline engineers and they have said if there is even the slightest bit of slack in any of the linkages or ball joints theres your problem, i usually have to replace about 2-5 steering linkage asy. a month,to much pressure for that small joint at the pitman arm.

My taco has a death wabble with the back end lifted up more then 45psi

^^^ your death wobble is caused by a severe roll-steer issue, not the same thing that causes the wobble on the lifted trucks.

I have seen poor alignment, bad tires (even if they look good), worn out parts, poor suspension geometry, lack of pannard bar, all cause the death wobble. So to give you any sort of difinitive answer is impossible. I would have to agree with Travis that it is most likely a over-stressed part that is causing the problem tho.

this is a long shot but was it in 4wheel drive at the time? A lot of the lift kits out there don't recommend going over 30-40mph in 4wheel drive.