changed oil and filter like i have for what seems like a zillion times, only this time something strange has happened. car is 89 245 with 250k on it and the aw 70 trans.

the trans has been a little finincky on it's upshifts, but no big deal, i can live with it. but after changing oil and filter, i noticed oil warning light would come on when trans shifted from 2-3 then 3-4. it would be barely come on then go off. at speed and in 4th it was off. but, everytime the 2-3 and then 3-4 shift was made, the light would appear. oil level is fine, drain plug tight and filter is same fram model i've used a million times. coincidence maybe bad sensor , bad filter or something else. no overheating etc, so just the light coming on is the worry. may just change out filter to be sure. is this an occurrence someone else has experienced and i should really worry bout, or just a nuisance of bad sensor?

thanks
gary c.