Warped driveshaft concerns.

Bassani50 · Jan 21, 2009

I'm pretty sure that my driveshaft has become warped, starts vibrating the car pretty good at about 70mph, calms down slightly during acceleration, sometimes during deceleration, as I said, Im pretty damn sure it's the driveshaft, but anyone else have any bits?, the previous owner had "installed" 3.73 gears, Could this also be a concern?, car is TOTALLY smooth till I get into some speed, or basically get the driveshaft spinning at a higher rate of RPM's... Any techs able to confirm my theory?

Bassani50 · Jan 21, 2009

I'm pretty sure it's not a transmission mount, I've made sure to check the hardware and the bolts for looseness, everything is in and tight from replacing my last clutch release bearing

El_Diablo · Jan 21, 2009

when was the last time the u-joints were replaced??? no grease-able are stronger and last longer.....

CC'S95GT · Jan 22, 2009

+1 on u-joints.

mikey94gt · Jan 22, 2009

I would check u joints, then mark the driveshaft upon install. when you still have the vibes, turn it 90* relative to the input flange on the axle, to try and balance the whole thing as an assembly.

Bassani50 · Jan 22, 2009

U joints? really? I thought it could have been the shaft, I'll give it a good gander this weekend at my old man's house, that ****** has a lift I can get it on and really get a look, U Joints... So what am I looking for basically, Bad clips? or worn out bearings under the caps?

Bassani50 · Jan 22, 2009

yeah, U Joints most likely have never been replaced

CC'S95GT · Jan 22, 2009

get it on a lift with the wheels unloaded and push up and down and side to side on both ends. i had u-joints going out on my truck and the vibs were so bad, on the hiway i could't see out the rear view.

rgs · Jan 22, 2009

i get very bad vibrations at around 85-90 mph. i've replaced the u joints on my car once before... wonder if they would have went again?

CC'S95GT · Jan 22, 2009

rgs said:
i get very bad vibrations at around 85-90 mph. i've replaced the u joints on my car once before... wonder if they would have went again?

at that those speeds could be tire balance, harmonic balancer, rear end bearings, trans bearings, etc

topless95 · Jan 22, 2009

mikey94gt said:
I would check u joints, then mark the driveshaft upon install. when you still have the vibes, turn it 90* relative to the input flange on the axle, to try and balance the whole thing as an assembly.

You would need to turn it 180 degrees

El_Diablo · Jan 22, 2009

if you're going to take the time to take the caps off, spend the money and get two new ones for $35(tops), cheap insurance...

Jrgunn5150 · Jan 22, 2009

Bassani50 said:
the previous owner had "installed" 3.73 gears, Could this also be a concern?, c

Before I knew how to rebuild transmission and rearends a few years ago, I had a local shop install some 4.10's for me... Had the same problem, bad vibrating at speed, coming up through the shifter.

I goofed around with the exhaust for days (it was also new, thought it might be rubbing) and finally my T45 cracked in half... Rebuilt it, it cracked in half again. Had Promotion build one, cracked in half.

I was moving to California and the second one I rebuilt cracked in half for the FOURTH time in like four months.

I bought a Viper spec T%^, had it shipped to where I was, rented a garage bay, bought a dial indicator and went to swap the 4.10's for 4.30s, and found out the assholes at Akron Horsepower put my rear end together with NO SHIMS!!!

My advice, get it up to speed, get it to do it, and throw the car in neutral, that will narrow it.

427danderson · Jan 25, 2009

I had the same problem on my 94 GT. I replaced my driveshaft with the Ford Racing Parts Aluminum one and NO MORE vibrations!! This drive shaft comes with two new U joints as well... I would check those too.. but for the money you can get a new drive shaft, a little more performance (a little), and two u joints... much easier to install too..