I recently bought a Bonneville 93, when I shift gear from P to D or R, I can feel the car strongly jerk. Is it unnormal ?
Someone said the transimission is worn, need repair. How much would it be to repair it ? Thanks a lot.

Sounds to me like at least one of your engine mounts are shot!

Yup, that is what I am thinking. Look into some new engine mounts.

I dont know if its the same as what was happening with my car but try not pressing on the gas quite as fast after shifting... give the tranny a minute to get into drive before you go.. It solved my problem..... just a suggestion

Shift the lever into the "P" (Parking) position.
Start the engine, and wait until the engine rpm has reduced to normal level (650 - 850 rpm).
With your foot holding down the brake pedal, shift to the "R" (Reverse) position. After only a short delay (0.3 - 0.8 seconds), the transmission should engage (you feel smooth push towards the back) very smoothly, without a jerk. Shift to "N" (Neutral), and the transmission should release. Then shift to the "D" (Drive) position. After the same short delay (0.3 - 0.8 seconds), the vehicle should twitch smoothly forward, also without a jerk. Now, still holding the brake pedal down, try to shift from D to R and vice versa.
! If there is any strong jerk or noise while shifting, avoid buying such a car.
! If there is a long delay (more than 1 - 1.5 seconds) between the moment you shift the lever and the moment the the transmission engages , such a transmission is either too worn or has some defect, avoid buying such a car.

i had a simillar problem 2 weeks ago, when i bought the car, i would give it a little gas and hear a nice clunk sound, i got my wife to hold the brake down and i popped the hood and gave it a little gas, and sure enough, my engine was moving up with acceleration, ended up being my front transmision mount was broke in half, really bummed me out being as i just bought the car and had overlooked that. anyhow really easy fix. Good luck and hope you solve your problem.

i was having a similar problem on my old 90 bonnie. once i replaced the Half Shafts, the problem nearly disapeared.