Had this issue for a while and nothing noted with the other jobs I've had done on the car. There is a vibration when accelerating uphill often between 1000 and 2000 revs. Noticed on MOT before I got the car it said minor rear diff leak. The vibration feels like it comes from the rear and sometimes almost like wheels are breaking traction, hard to explain. Any chance it's diff issue from low oil? Having service soon so can ask them to check. Before torque converter was mentioned but it gets no worse and just cracks on like this for quite a while.