Hi
You probably have a 'Death Wobble'.
Lots of posts on that buzzword.
Technically it is a resonance swinging of multiple components in the front axle, made possible by too much play.
In many cases this is not caused by a single culprit, but as a combination of multiple parts that have each have a bit of play, which sums up and causes 'too much play altogether'.
Trigger may be an unbalanced mass, eg of a wheel.
In essence it comes down to:
- Check your entire front axle and steering gear.
- Start with the easy stuff: Check wheels for uneven wear, balance wheels, swap wheels rear to front, do wheel alignment/ check caster and toe, check wheel bearings for play, check steering gear and tierod ends for play, thighten suspension and shocks, stabilizer links, u-bolts and spring clamps if leafsprung.
- If that doesn't help: Get more serious with suspension and stabilizer bushings, swivel bearings..
Often the play is caused by worn bushes and tierods.
On modified / lifted rigs, caster and other geometry issues contribute to the effect.
Sometimes really the wheels are the culprit, despite all balancing, alignment and proper pressure. Changing to a different set of wheels (eg boroughed) helps the diagnosis.
You need to check thoroughly. Torque every bolt to spec, even those you can't imaging to come loose (eg pitman arm, steering box to frame bolts). Move things, if needed by pry bar and observe closely.
Good Luck Ralf
