Driveline vibration

[90LX5spd]

My '90 LX 5 speed has developed a vibration in the driveline. One day it was fine, the next it started. The vibration gets worse with speed. It starts to become noticable at 25 and becomes progressively worse as speed increases. It does it in every gear, even if the transmission is pulled into neutral and the car left to coast. These things had me thinking wheel balance, EXCEPT the vibration goes away whenever the throttle is applied. A little throttle or alot, and no vibes. As soon as I back off the throttle, the vibes return. So it vibrates on decel, throttle off cruising and tranny-in-neutral coasting. Any ideas? The car has been driven easy (nothing over 3000 rpms and no overly hard driving) as the motor is still in the break-in period (under 300 miles). Thanks.

 

[craigwhite89gt]

1st thing i would do is check drive shaft bolts. Check engine/ tranny mounts also. make sure they havent wore out.

 

[seijirou]

Yeah what he said.

Look for play in the ujoints while you're under there, and take a peek at the ends of the driveshafts and see if you threw a weight. Throwing a weight will give you sudden vibration like a switch.

 

[90mustangGT]

1st thing i would do is check drive shaft bolts. Check engine/ tranny mounts also. make sure they havent wore out.

Do that, and if that is all good, check U-joints.

Worse case, the rear end could have a problem on setup, the coasting side of the gears not aligning correctly or a bad berring.

 

[Mark89coupe]

My '90 LX 5 speed has developed a vibration in the driveline. One day it was fine, the next it started. The vibration gets worse with speed. It starts to become noticable at 25 and becomes progressively worse as speed increases. It does it in every gear, even if the transmission is pulled into neutral and the car left to coast. These things had me thinking wheel balance, EXCEPT the vibration goes away whenever the throttle is applied. A little throttle or alot, and no vibes. As soon as I back off the throttle, the vibes return. So it vibrates on decel, throttle off cruising and tranny-in-neutral coasting. Any ideas? The car has been driven easy (nothing over 3000 rpms and no overly hard driving) as the motor is still in the break-in period (under 300 miles). Thanks.

I used to get a serious vibration also. It was the tailshaft bushing in the tranny.

Not hijacking but-
I replaced the tranny and now I get a vibration at 80mph or better. Im guessing its the rear gears? Or possible the rear bearings? My rear tires are balanced.

 

[S&B]

well i had the same problem once and I swore it was the d/s i had everything ballanced and all. then i checked every ignition wire, and yup one was burnt out, i was having a miss that got worse with speed. so you might want to also check your cap and wires.

 

[90LX5spd]

It was indeed the driveshaft bolts. At first glance they appeared flush with the flange but after putting wrench on them, I found 3 had just begun to loosen. Its funny you mention the ignition wire. My wife's Crown Vic Interceptor did the same thing and it was just a bad wire. Thanks.