i have a great 93 legacy turbo sedan with 160k that has suddenly caught a transmission cough. gear shifting from 2nd-3rd is hesitating for longer split seconds than normal and then clunking or dropping into gear. this is very easy to detect while accelerating mildly from a stop. if i take it really easy while accelerating, hesitation with less gear clunking is noticable especially 3rd -4th gear. stop and go driving in the city is the best way to experience the hard gear changing from 2nd-3rd gear.
ive tried additives into the tranny for gear smoothing and shuddering and have noticed no improvements, rather the symptoms are graduating into longer hesitation and slipping.
i'm not sure if a heathy automatic's transmissions gears are very active when decellerating... helping to break the car. ive noticed that the rpms are very inactive when coasting to a stop over a significant distance on the highways.
ive ran both d and u tests and found codes 51 and 42. inhibitor switch and idle switch respectively. could these be related to the tranny?
ive been trying to brush up on the matter of rebuild or replace through other posts and am wondering if there is such a thing as a sure-fire rebuild or are they just a short term 50k fix at best???
what about throwing in a shift kit from transgo or the like? could the kit or something else possibly cap the hesitation and shuddering/clunking problem and slow the tranny's death to a significantly slower rate? also,
would adding and new tranny filter and radiator contribute to the cause?
all advice and replies are appreciated greatly

paul