Ok going to explain this the best I can.
My '94 Mighty Max has been shaking at high speeds. It drives great around town
but it seems whenever it is under load (on an incline, or occasionally straightaways)
at a speed greater than 65 mph the whole truck shakes. Taking my foot off the gas
makes the shaking less intense, and pressing my foot down on the pedal makes the
truck shake worse (there is also a low chugging/rumbling sound). When I release the
gas and drift down to a slower speed (55mph) the shaking disappears completely.
This makes me think it is either drive shaft or transmission related - and not tires. In
other words, the gas pedal is directly related to the vibration.
Things I've replaced: Ball joints, tie rods, sway bar and strut rod bushings, fuel filter,
distributor cap, plugs, air filter, brake pads and rotors.
Front suspension is tight. Still shaking.
Now how do I test for play in the drive shaft? I see no leakage and I can't turn it or
detect any movement in the u-joints or yokes with the truck off. Is there a more precise
test I can do?