[kreil45]

89 GT with 3.73 rear. get a vibration between 75-80 in the shifter,console and the radio console. i dont get at any other speeds. i thought it might be in the rearend or in the drive. but some one told me it could be the motor mounts. any thoughts?

[TurboLX]

sounds like a loose tranny mount or a short driveshaft

[neverfastenough]

Auto or stick? Just in the console none in the wheel, huh? when you reach that speed and let your foot off the gas or does it do it even if you power thru that speed? Sounds like it could be one of the mnts. If its an auto, I have heard people get bad vibration at speed from a bad t/c. Could be universal joints. Could be a bad pilot bearing. I'd start with the easy to check stuff like u/j, and the mnts and pray it is one of them.

[kreil45]

sorry, manual and it only happens in 5th gear

[86blkmustang]

Check ur u-joints

[sniperrider]

yea check the u joints, i just had that problem while decellerating it was the driveshaft loose, so crawl under there and check that, and check the rubber pieces they may be bad, or would it be as simple as tires being un balanced

[STANGDOOD]

PLEASE!!! if you find out what is causing your vibration let me know because I have the exact same problem with my 89 5.0 gt 5 speed too. all bushings and mounts are new, engine freshly rebuilt but still vibrating??

[STANGDOOD]

Hey.. I was talking to a guy that has a Mustang performance shop the other day and he said that he had a Cobra with the same problem and after changing the obvious things it ended up being the tail shaft bushing in the transmission.. has anybody tried changing that yet??

[White 89]

IT IS YOUR U-JOINTS.

I had the same exact problem. Real bad vibrations at higher speeds. Everything in the car vibrating the dash all that stuff was vibrating.

It's your U-JOINTS

[1slo5.0]

Originally Posted by kreil45 89 GT with 3.73 rear. get a vibration between 75-80 in the shifter,console and the radio console. i dont get at any other speeds. i thought it might be in the rearend or in the drive. but some one told me it could be the motor mounts. any thoughts?

Could be bad u-joints or a bad transmission. Both cause the problem you are having.

[Hunt_chevs]

i shall check these u joints of mine,...

[STANGDOOD]

Just a new note.. I'm still having the problem after changing the pinion angle from tranny to rear end but it did get a little better.
Now I just found out that changing to a Tremec Transmission and using the stock length drive shaft will also cause problems, they make an 11/16 spacer to correct the length for about $40.
Now I am going to try a new ALUMINUM Driveshaft and possibly a new transmission tail shaft bushing, I hope this works cus trying to fix this vibration is costing more than I paid for the car. I've already changed the whole rear end, new 3:73 gears, 5 lug conversion (so I could eliminate axle possibility's) new deep dish bullit wheels and tires and changed every bushing on the car from motor mounts to rear end, I'm getting to the end of my teather.

[TKOTLARZ]

make sure all ur bolts on your tranny are tightened, that was my problem

[92hatchback]

just had mine fixed yesturday.. mine was the ball joint.. fix it asap if it is because mine went while driving and shot my a arm onto my rim and screwed some stuff up..

[e3sean]

there are a few things it could be. the u joint is a good possibility and that is an easy fix.
your driveshaft could be slightly out of balence and that is an easy fix but you have to take it to have checked and balenced uausally costs about 60.00
coult be the transmission does it feel sloppy? how many miles are on it since the last rebuild? do you drive it hard?

[patwrecked]

i say get the drive shaft checked. does it vibrate more when you let off the gas and get back on. do that at speed. i bet driveshaft.

[Hunt_chevs]

sounds like an output shaft bearing,..