Join Date: Dec 2002
Location: Central Alabama, USA
Feedback Score: 0 reviews
OK, I haven't answered this question in a long time. I will once more for those that are interested in understanding "cause" not treatment of symptoms. So far everyone is wrong and claiming that treating this or that symptom solved the problem, it did not it just moved it from a diagnostic perspective.
The issue is lack of stiffness, low mass, low energy degradation system and a phenomenon called resonance. Given enough source force impact any assembly can be made to resonate energy at its natural frequency or the net natural frequency of multiple assemblies mated together, system natural frequency. An object being impact resonated will act as a force multiplier of 10 to 50 x the source force. Given enough force some assemblies will maintain this system of vibration energy with a very low continuing source force after the starting impact. In the vibration diagnostic business that is called locked resonance. Once a vibrating system is created very little energy is needed to keep it going like swinging a child on a swing, the major energy required is starting the system to vibrate, then just a small cyclic push will keep it swinging. That is why some report that they hit a pot hole, a RR track, a curb or ran it with severely unbalanced tires and had to come to a complete stop to eliminate the shaking. The follow on source force didn't have to be as severe as the big starting impact to support the vibrating system.
Some things make it make likely, mechanical looseness, front end mods like bigger tires, bad steering dampers, and unbalanced tires. That's the cause, but its a problem that has to be managed by symptoms or peripheral parts. You cant change the "cause" physics, it is induced resonance amplitude. Think of a bell, impact it and it acts as a resonating force multiplier. Sure , you can dampen in but given enough source force it WILL resonate. Oneof6
2002 F250 7.3L PSD, bought new now at 226K miles, 4R100 Auto, Crew Cab, Short Bed, ITP Regulated Fuel Return system, ITP head to head SS oil cross over, Hutch in tank mod
Harpoon de tank vent, DIESELSITE Dahl 100 Pre-Pump Fuel Filter, DIESELSITE Return Fuel Line Cooler, DIESELSITE Engine Coolant Filter, DIESELSITE Auxilliary Transmission Cooler, DIESELSITE Gage Package, Pyro, Trans & Boost, Extreme Diesel AD injectors, Ford AIS Air Filter System, BTM straight through muffler, Moog Ball Joints, Rancho Shocks, Rotella ELC Coolant ,Stock Engine Program
Modified for I-Pod Connection
We b playing Scotland The Brave to Jimmy Hendrix