loud howl, violent shake, stuck by the roadside

[bumper crop]

i have a '67 f100, 300 i6, c4 (recently rebuilt).

today i was on the highway when a very loud howl started coming from under the hood, and the truck began to shake violently.

i pulled over and popped the hood, and could see some smoke, but it dissipated before i could figure out where it was coming from.

my first thought is that the starter became engaged and began burning out. i can still start it though, and in park sitting still it runs great. when i put it in gear and drive it, the same thing happens again after traveling several hundred feet.

could my starter be freezing up? cracked flexplate? any other ideas?

seems to shift normally, so i dont really suspect the trans itself. anyway, words of wisdom are greatly appreciated.

thanks,

mark

[basketcase0302]

Mark,

Kinda' hard to diagnose from the description but I'd say you've already narrowed it down to the C-4 area, (transmission). I'd pull the inspection cover and check the four flexplate nuts / verify the vacum line to the tranny modulator valve is intact from the engine to the transmission / check the tranny fluid. I'd also make sure all the cylinders are firing, (pull one plug wire at a time while at idle). Any fluid leaks around the transmission evident?

[bumper crop]

been thinking maybe front u-joint. or maybe the flexplate bolts maybe loosened since the rebuild. trans fluid is topped off properly and looks fine.

engine is running fine. i dont think it's missing at all.

[michael69]

How about the balancer? Is it on tight with no slipping or wobble?

[Whateverman]

another place to look if its a LWB with a 2pc driveshaft - the steady bearing can sieze up and spin in the rubber bushing ,it'll cause howling,a whole lotta shaking (big time) and smoking

[bumper crop]

thanks guys. i'll take the list to the shop and check stuff out this weekend. will report back with progress...

[tod-hog]

I once had a fresh rebuild do this. Turned out the tranny cooler that was built into the radiator (brand new) was bad. Burned up two trannies before figured it out.

[bumper crop]

just to keep everyone up to speed, the problem was a bad carrier bearing and, as a result of that failure, bad middle u-joint. a new carrier bearing and 3 u-joints later, it's good as new.

except the TSS failed on the test drive...