Back from 6 days away towing the caravan. No problems with the D2.
The main difference between running a stock 4L and gearbox, and running an "improved" 4.6 and stock gearbox is-
If you give it a bootfull the engine now holds its higher revs and the gearbox has to catch up to lockup..
whereas with the 4L the engine would slow down to lockup.
its still happy to pull away from less than 60kph with the caravan on and box locked in 4th.

