I "think" the belwo diagrams are of your trans (722.3) and that it is controled by vaccum and throttle position like earlier models were.
http://www.detali.ru/cat/oem_mb2.asp?TP=1&F=126035&M=116%2E965&GA=722324%5F09Y&L=765%2E706&VIN=%2A&CT=GA&cat=09Y&SID=27&SGR=001&SGN=01
Qualifier: I dont know this model and am reaching.....The below comments helped a 722.1.
If it was shifting good previously and you've been working in the engine compartment is it poss you've knocked a vaccum line loose or have rubber fittings that have been distrubed or are cracked and leaking? Do door locks work and hold vac for days on end? AC vents open/shut well?
You can tweak softness/firmness of shifts by adjusting vac to trans (see #607). Clockwise = firmer. 1/4 turns at a time only, then road test. Adjusting the bowden cable will change the rpm at which the trans shifts which can help some issues such as flaring.
That said, as was already pointed out, you've got a lot of miles and are def in the range where trans do give up. Yours was a popular model, a lower mileage donor trans may be less expensive than a rebuild.