98 jimmy tranny diagnosis/service help!!!

Transmission has been slipping and hard-shifting for some time now,about 8 mos, have been somewhat paralyzed about what to do about it(mainly the associated costs have me in this state), but I've decided to at least get it serviced for now as well as some research. With a new filter, a proper flush and GM's new-spec Dextron 6 I guess I'll go from there and see if that helps. A few questions come to mind that maybe someone could help with. Are the bands serviceable, can they be tightened? What are the most likely things to be failing when slipping is occurring? Clutches? Bands? Torque converter? Clogged filter? All of the above?? Also, how often do tranny's need a complete flush/filter change? And lastly, am I too late to salvage this one? maybe time to start saving for a rebuilt/d? Truck has about 225,000 kms on it.
Thanks for any help. Daryl.

Transmission has been slipping and hard-shifting for some time now,about 8 mos, have been somewhat paralyzed about what to do about it(mainly the associated costs have me in this state), but I've decided to at least get it serviced for now as well as some research. With a new filter, a proper flush and GM's new-spec Dextron 6 I guess I'll go from there and see if that helps. A few questions come to mind that maybe someone could help with. Are the bands serviceable, can they be tightened? What are the most likely things to be failing when slipping is occurring? Clutches? Bands? Torque converter? Clogged filter? All of the above?? Also, how often do tranny's need a complete flush/filter change? And lastly, am I too late to salvage this one? maybe time to start saving for a rebuilt/d? Truck has about 225,000 kms on it.
Thanks for any help. Daryl.

If it has been slipping and hard shifting and never been serviced it is to late for a filter and fluid change.
There is no adjustments on them.
A good engine transmission capable scanner should show problem.