Can you elaborate a little? How do you know it's the transmission? Describe the vibration. Is it only at 45 mph? Does it vibrate when you let off the accelerator?
This is a transmission problem indiginous to certain Chrysler models with the 3.0 and 3.3 litre engines. The transmission will need to be opened and worked on. This problem cost me 2300 us dollars about 4 years ago.
clean your injectors
Check your "Kick Down" cable. It helps you transmission shift into the passing gear. If it is stretched or simply worn out,it may cause the problem.
4987 mph
Stock? 160+ mph Modified? Over 200 mph
149.1 Mph
It was clocked at Daytona at 154 mph.
Bad CV joint? How about a bad steering box?
Check the transmission fluid level, be sure it is at the full line. A worn out universal joint could be the source of the clunking noise when the transmission is shifting.
The maximum speed of the 1962 Plymouth Sport Fury is 105 mph.
Sounds like wheel imbalance or driveshaft, if it's been out recently.
From the Earth to the Sun 75 MPH 160 years 500 MPH 24 years 1350 MPH (mach 2) 8.8 years 40,000 MPH (Voyager speed) 4 months