ggggrrrr, transmission woes!

[SoLoDoC]

Alright I've had my 1990 automatic 240 sx se since Thursday morning. All day Thursday while driving, no percieved notion that there was a problem with engine or transmission. Since Friday, going from 1st to 2nd there is a almost violent jerk. The rest of the gears, 2nd to 3rd and 3rd to 4th there is a long lag in terms of shifting. The overdrive or the torque converter is also lagging when i turn it off and then turn it back on. Also when I park, shifting from Drive to Park the car jerks or shakes. Is this my transmission or throttle position sensor? I'm guessing transmission. If anyone has any suggestions on my problem i would appreciate any comments. I know that a private sale is buyer beware but jeez, why is there a difference between my driving experience on Thursday and since?

Is there anything that the person who sold the car to me could have done to make the transmission run smooth for one day?

Thanks in advance.

[240SicknessX]

well ur car is a 90 and the auto has some miles on it, so its not going to shift like a mercedes....... when my automagic s14 is cold, upshifting into second is sometimes a quick hard shift, then second to third is easier...... its just when you are going a a faster rate it takes more addional intertia to exert the same force on the car as if it were goin 10-15 mph going from first to second. i have about .5-.7 seconds of lag when im turning OD on and off, its normal. and the jerk from drive to park is just coninsidence that your sprag gear isnt hooking on the perfect tooth on the *insert name for auto flywheel subsitute here, the starter grabs this geared wheel to start the vehical*. if your concerned about your transmissions health, change the fluid and filter.

** to prolong the life and dont exert as much stress on your auto, make sure that you are at a complete stop before changing from or into Park Reverse or Drive.

PS. remember the d stands for drift, thats one thing that a 5spd dosent have, lmao