I am a past Teac Technician. The answer may be a bad capstan belt- is the round metal thing rotating that makes contact with the rubber Pinch Roller? These belts become lose over time and the DC motor become defective in time due to wear- Before they burn out they can be serviced but only by a person with knowledge about how to take them apart. Otherwise the part can be $120 plus installation. I have not seen sticky Pinch Roller linkages in these models so I will say it is probably not that.
If you are near Chicago I can help you out. If you are near New Jersey Russ can help. If you want to discuss, contact me.[email protected]
I work on all Teac and Tascam units now full time.
I am also known on tapeheads.net as well.