My Mav starts to vibrate at about 40 MPH and continues to do so through about 70 MPH. I put the car in idle and revved the engine through different RPM's, and the car vibrated at almost every RPM above 1000. The vibration is not constant either- it comes in cycles depending on how fast the engine is revving. Does this mean that the mounts or balancer are bad? Does the vibration possibly have anything to do with the u-joints ? (The car clunks into reverse; this is why I suspect the u-joints)
If the vibration is exclusively when the car is in motion, then u-joints are a very likely culprit. That's exactly what happened to my Cherokee. That could account for the clunking when you shift also. If it does it when the car is still, then something else is going on. Motor mounts can be a cause. I'd check the trans mounts also.
well i can give you 3 possiblities on the engine vibration. as far as clunking when you put it in reverse, it either a u-joint or way too much backlash in your rearend gearset. how smooth does the engine idle? You may have a dead cylinder(need to run a compression check) another thing to look at and ford engines were very bad for this. check your harmonic balancer and make sure it hasnt "slipped". The balancer has a ring with a rubber layer seperated the two. the rubber gets old and the ring tends to slip around and throws the engine out of balace. best way to check it is to take the NUM 1 plug out find top dead center and see where the timing mark is at. if its not at zero then it has slipped. another possibility is that your torque converter is coming apart which is rare on a ford ( normally they just go with no warning) but possible. Does the tranny seem to shift ok?
I hope the clunking is the u-joints and not something wrong with the tranny- The car has always shifted smoothly. The idel is also very smooth; I've run several compression checks on the engine and each cylinder is fine. Where is the harmonic balancer located (I've never had to deal with anything like that!)? Is it an easy fix? Thanks for the info!
the harmonic balancer is bolted to the front of your crank the timing marks are hashed on it. the only fix is eiter to replace it or there is a company that can redo them. if that is the trouble and you want to have it redone let me know and i will find the number for you. its in the hemmings motor news somewhere...... usually harmonic balancer replacements are pretty expensive so its either have it redone or off to the boneyard!
Sounds like the U-Joints. Replace those first and then if the problem persists check the other things. A lot of the time the problem is caused by something simple (like u-joints in this case). -Corbin
except he stated that he put the car in idle and revved the engine and it still vibrates. which im sure he actually meant he had it in nuetral but i understood him. you cant rev an automatic in gear you know
