While cruising at approx 1800-2000 rpm steady my rpm will increase approx 200-300 and the transmission will seem like it downshifts out of overdrive and then will find overdrive again. above 2000 rpm and 65 mph things work just fine.

The trans does not kick down to 3rd as if it did it would run at 2500 rpm.
I do not have this problem if left in 3rd only in OD.

If I touch the break slightly the trans will jump about 300 rpm and I dont have the problem of the erratic shifting. Sure do not want to go around riding the brake though.
Could this be a torque convertor problem or is it in the transmission.

The old girl does have a few miles on her about 270,000.
Thanks for any help.