fisher2985

i've gotta bad driveline vibration above 70 mph. i think its coming from the tranny bcus it only seems to do it in overdrive. (had the same problem before the 4.10's, thats why i changed gears). anyone else had any problems with there auto tranny?

EODMustang

I'm having some weird issues like that too. At high speeds I get a lot of noise from the underside/back of the car. I also get some whining noise too. I know that mine is a rearend, not a tranny issue, so it may do you some good to check out the rearend. Do you get the sound, but less noticeable, at lower speeds?

fisher2985

i just swapped to the 4.10's and rebuilt the rearend. but i did this because of this problem, (didnt fix it though) so i dont think its gear related. i really think (after hours of research) that the driveshaft is out of balance. gonna try a used driveshaft for $50 and will keep u updated on what happens.

EODMustang

That driveshaft idea sounds like it could work. I'm gonna look into it myself. Definitely let me know if it solves your problem.

DR.DIESEL

do you have a bunch of up and down movement where your drivshaft goes into the trans.it might be a tailshaft bushing thats worn out.

fisher2985

naw that's tight. (1st thing i checked) still think its a driveshaft just trying to find someone to balance it.

1bdhrse

went to the track this weekend and I have the same problem. Seems like 3 to 4 gear i have a weird vibration at lower rpm's. Automatic tranny 37,000 miles on my 01.

justag6969

n e news???

school boy

mine dones the same vibration going into overdrive. thought maybe torque converter?

cliffyk

IT is not unusual to have driveshaft imbalance show up at higher speeds when you install lower (numerically higher) rear-end gear.

For example, with the 4R70w at 80 MPH, in overdrive with the stock 3.27 gears, the driveshaft is turning 3570 rpm--switch to 3.73's and the driveshaft will be spinning 3930 rpm.

With 4.10s the driveshaft will be running at 4570 rpm.

That's 1000 rpm, and 28%, faster than with the stock gears--with the stock gears you'd be going 105+ mph at 3200 engine rpm to get the driveshaft spinning at 4570 rpm.

For some reason the automatics seem to be more prone to this phenomenon, the driveshafts may be different, IDK...