hey guys got another problem. My bronco (89 2.9L 5 spd 4x4) vibrates pretty badly when im accelerating or even holding speed above 2500 rpm. this kills me when im going 70 on the highway to and from work every day. (limit is 65, most people are passing me.. dont need anybody to tell me just to slow down) Anyway as soon as i let off the gas the entire thing smooths out like glass. So i know its not tire balance. Is my engine off a little, driveline not balanced, some kind of clutch problem??? I know my throwout bearing is almost gone cuz it clunks whenever i start out and change gears.. could it have anything to do with that? Oh and one other thing.. dont think im a jerk because of the signature.. i just barely put it on and couldnt think of anything else.

 

Do you still have the stock rezeppa CV-style driveshaft? When the CV joints are in bad enough shape, they will cause a vibration on acceleration that can feel a lot like clutch problems. That clunk when you start out and shift could also be attributable to the driveshaft.

 

well i had no idea what a cv-style shaft was so i looked it up on lycos... turns out no. The site i found shows the old stock style and the conversion (they call it ss-4 i think).
Any other ideas?

 

Have you looked at the engine mounts, I know it sounds silly, but can definetly cause a problem, more power more shakes, push in the clutch idle the engine down and it goes away, always a possibility

 

Did you check the condition of the u-joints then? Any slop in the joints?
Engine/transmission mounts is another good thing to check.

 

I'm going to fall in with the u-joint crowd here as well. My girlfriend has an 85 that the joints went bad in and would only vibrate under power. Completely destroyed her transmission from the vibrating. Yeah, she let it get THAT bad. Cracked case and all. But that's an extreme case. I would get under there and wiggle and turn and shake until I figured out what was loose or worn out.

 

Well guys, vibrating was from bad u joints. I thought my throwout bearing was gone too cuz i clunked when i would let the clutch out... also due to the bad joint. Well excuse my lack of correct terminology, but it was the cross thingy between the u joints.. you know, the part that connects the two U's. Anyway I took it to a driveline place, 26 bucks and four hours later it had both "cross thingy's" replaced. Guys this thing was BAD!!!!! It had almost broke all they way out. One good clutch drop or spinning in the mud and a sudden catch and it would have been a front wheel drive bronco. Thank you guys so much for pointing me in the right direction. It was doing it for about a month but has gotten a lot worse in the last week. Hopefully i didnt screw up anything else... but lets say i did.. what would i look for now? That tranny like you girlfriends? Anyway at least for now my bronco rides incredible. Thanx again fellas.

 

hey i had to let you guys know... the day after i fixed it i was cruising down the highway going 77 in a 65 cuz it felt so smooth.. got a speedin ticket. sucks huh.