Hey guys. I started getting a slight vibration at 40 mph about 5,000 miles ago. It would occur when I would reach 40 coast a little, and then go to accelerate. I drained 3.5 quarts of transmission fluid at 55,000 and then at 60,000 miles. I replaced it both times with matic s. It seems like now the vibration is worse. What gives? I thought new fluid would help and not make it worse. The only other thing I did was change the diff fluid with Amsoil 80w-90.

 

Use vibration software and test equipment to measure accurately the FREQUENCY of vibration and harmonics along with intensity of each.
http://www.vibratesoftware.com/html_...ion_School.htm

Freq: 10-200 Hz with a sensitivity of 0.01G

After rotors, wheels, tires are checked then check drive shaft for damage [lost balance weight] and runout per FSM specification. Also engine motor mounts, transmision mount, differential mounts/isolators.

Without frequency vs speed data everything is a guess.