So here's the sitch: driving down a remote but not impossible road into the desert. Hit a washout harder than I'd have liked but not hard enough to worry. Truck gets noisier and begins vibrating pretty badly. Feels and sounds like a really bad U-joint or driveshaft problem.
The vibes are noticeable over the normal clatter of the truck over 1500 RPM and worsen up to 2200 or so. They are still pretty bad at 3000 but smooth out over 3200. They aren't completely gone, more like the frequency increases enough to dampen the shaking
The vibrations are very specific to engine speed. Not road speed. The truck vibrates just as bad sitting in the driveway with the transmission in neutral and the clutch in as it does motoring down the road.
So, after isolating the motor I am ruling out:
Tires, wheels, axles, prop shafts, gearbox.
I though at first, because of the hard jolt that a motormount gave out. But they appear sound. I stuck a floor jack under the motor and lifted it while inspecting both mounts and they seem fine. Anyway, I wouldn't think a loose motor would shake only with relation to rpm...
I read where some guys were having a very similar problem with their harmonic balancers on 3fs, 2fs etc... But were observing a bushing failure of some kind. The 20R / 22R / RE don't seem to have this bushing. Rather the balencer is just press fit, machined steel. I don't see what could fail there unless the crankshaft end was all wallowed out. The pulley spins true, without any discernable noise, and has no end play or wobble. It seems like a failure here might damage the front main seal as a result but no oil leaks here.
I put a clutch in the truck six mos. back. I started wondering if it was possible that the clutch/pressure plate assembly had slipped out of alignment and was off center on the flywheel. Is this even possible or does the input shaft from the gearbox prevent the possibility?
The flywheel was in good shape at the time of the clutch job. Someone asked if it maybe lost a weight and was unbalanced but the flywheel has no weights by my recollection. True? Thoughts?
I also checked to see if the timing chain tensioning block(s) had broken but the appear to be intact. I don't know the correct tension on the chain but the left side (carb) is taught and the right side (distributor) has an eighth inch of slack or so. Seems ok to me.
I'm contemplating dropping the transmission . But don't really wanna if I don't hafta. Anybody have any input here. I'm at a bit of a loss
The vibes are noticeable over the normal clatter of the truck over 1500 RPM and worsen up to 2200 or so. They are still pretty bad at 3000 but smooth out over 3200. They aren't completely gone, more like the frequency increases enough to dampen the shaking
The vibrations are very specific to engine speed. Not road speed. The truck vibrates just as bad sitting in the driveway with the transmission in neutral and the clutch in as it does motoring down the road.
So, after isolating the motor I am ruling out:
Tires, wheels, axles, prop shafts, gearbox.
I though at first, because of the hard jolt that a motormount gave out. But they appear sound. I stuck a floor jack under the motor and lifted it while inspecting both mounts and they seem fine. Anyway, I wouldn't think a loose motor would shake only with relation to rpm...
I read where some guys were having a very similar problem with their harmonic balancers on 3fs, 2fs etc... But were observing a bushing failure of some kind. The 20R / 22R / RE don't seem to have this bushing. Rather the balencer is just press fit, machined steel. I don't see what could fail there unless the crankshaft end was all wallowed out. The pulley spins true, without any discernable noise, and has no end play or wobble. It seems like a failure here might damage the front main seal as a result but no oil leaks here.
I put a clutch in the truck six mos. back. I started wondering if it was possible that the clutch/pressure plate assembly had slipped out of alignment and was off center on the flywheel. Is this even possible or does the input shaft from the gearbox prevent the possibility?
The flywheel was in good shape at the time of the clutch job. Someone asked if it maybe lost a weight and was unbalanced but the flywheel has no weights by my recollection. True? Thoughts?
I also checked to see if the timing chain tensioning block(s) had broken but the appear to be intact. I don't know the correct tension on the chain but the left side (carb) is taught and the right side (distributor) has an eighth inch of slack or so. Seems ok to me.
I'm contemplating dropping the transmission . But don't really wanna if I don't hafta. Anybody have any input here. I'm at a bit of a loss
