I’ve got a 3.6 TDV8 with about 180k miles on the clock and it has, by and large, been bulletproof. Last year, I had the transmission serviced and the fluids changed and it has been fine until recently. Now it has an intermittent stutter at around 50mph/1100RPM where it feels like the drive cuts out momentarily, almost like a slipping clutch.

Am I right in thinking a new torque convertor is likely needed?

i had an issue with my 4.4 tdv8, where i thought i had slipping drive... at around 50 mph, if cruising with a tiny bit of pedal to go a bit faster i was getting slight slipping, and was seeing the rev counter rise a tiny bit, and drop again, cycling like every couple seconds.... thought i was in for a torque converter... however, i decided to drain fluid and refill... to my horror, i saw the old fluid coming out grey and thick... my fluid cooer/heat exchanger had gone for a swim. so coolant had entered gearbox. had thoughts of doom about new gearbox, however, i filled and drained it about 6-7 times, and it works fine now. (after i changed out the heat exchanger. so, i would try and drain a tiny bit to see if it looks milky. nothing to lose.