1994 Mercury Topaz trans question

If you just changed the fluid and filter and that did not fix the issue , I would suspect bad pump in the transmission or a problem in the torque converter.

everytime the car cools down it will once again run smoothly. When changing filter and screen no metal in pan but what appeared to be plastic pieces possible gear. do you know what gears are plastic? Also, found small screw in pan thought was leftover from old filter before it sticks in 1st gear i've noticed fluctuation in speedometor. Any thoughts?

If you are talking about the little plastic cap, it is a seal for the dipstick tube in the transmission that keeps out dirt until the vehicle is ready on the production line to have the dipstick tube installed. No harm there.

If you mean literally small pieces, this would be the speedometer gear. This may be the cause of the speedo fluctuation you speak of as well. The contamination from the busted plastic gear can get imbedded in the clutches and bands (if any). Doing so will cause the transmission to have more damage creating a snowball effect doing more damage to itself overtime.

could it possibly be the govenor or linkage needs to be tightened??? (read a few other things online) or do feel new transimission is the answer or junk car all together. I guess I need to know if this is fixable without replacing transmission. Would rather junk it than replace transmission due to it seems to have one thing after another going on with it. I appeciate all your assistance.

Is tranny automatic or manual? Shift linkage would not have anything to do with it staying in first gear if you can move it to D (Drive). I would suspect internal problems with the tranny that needs to be rebuilt. You can have a local reputable tranny shop do a diagnostic on the tranny for around $50. This way, if the tranny does need rebuilt, you will know exactly what it needs so you can let the buyer of the vehicle know the repair estimates if you decide to sell it.

the transmission is automatic.