calinotch

I have a 92 notch 5 speed and when im at about 2500 rpms in 5th gear i get a nasty vibration. The shifter just starts rattling so i dont take it much higher than that. The car has 4.10s and i jacked it up to check slack in the u-joints. It rocked slightly but it looked like it was turning the output shaft too, so not the u-joints?

ryan_89_mustang

Is it 2500 rpms in every gear?? I had a vibration that would occur at like 30mph before and it shock the shifter like crazy and the dash as well. It was the front u joint, 1 cap only had dust inside and was mangled. The u joints can seize as well if they are not greased often. When that happened i could not see anything wrong with the u joints until i took the driveshaft off the car and had it out in the open.

wrenchturner75

i had a friends car that had a bad vibration in all gears and i thought a trans bearing was going bad when we pulled the trans out the nose of the input shaft had the inner bearing race siezed onto the shaft! here the damn pilot bearing self destructed and was causing the input shaft to wobble.

calinotch

nope its only 5th gear when cruising on the freeway.

Project 5.GO!

I have the same exact problem. I replaced the U joints about 3 years ago, and the problem has been constant for the last 6 years at least of the 13 years I've had the car... In 5th gear on the highway, if I go over about 85 mph (stock gears) the car starts vibrating, and the further around the speedo I push the needle, the harder it vibrates. Theoretically, I mean... I don't speed... Ever...

I think the problem has to be either an off-balance driveshaft, an out of balance flywheel, or it could be a tranny bearing? But all of those possibilities would result in vibration in any gear, right? And a driveshaft or flywheel don't just come out of balance by themselves for no reason, do they? What gives?

calinotch

my whole car doesnt shake though its just the the shifter and the tranny not the steering wheel or the seat or anything. i havent replaced the u-joints yet but i was just looking for a lead before i start buying parts for it.

HACKGT350

sounds like you need to think about checking the rear diff bearings.

to the op: are you sure your not feeling the vibration in the seat of your pants, its just in the shifter?

Project 5.GO!

Yeah, his is only through the shifter, and mine is the whole damn car. Diff bearings, eh? The car has 300k miles, so pretty much anything wouldn't surprise me!

HACKGT350

yeah i bet you its the diff. take the car out of gear and try to spin the back wheels by hand. when mine went it was almost impossible to spin the wheels by hand

Project 5.GO!

I just had it up on jack stands the other day to check the brakes, and the wheels spin fine... I know this because there was a little oil on the floor where I was jacking the car up, and when I took my weight off the jack, my foot went out from under me and well... Lets just say the side of my face spun the wheel quite well... Is it possible that it could still be one of the bearings, just that it isn't completely jacked enough to actually lock up the diff?