Hi folks I also have an early 300tdi auto.. with which i tow I have found that if i drop below 50mph it drops into 3rd and the fuel gets used up far more rapidly but if i maintain above 50mph it kicks into top gear and I can cruise along quite happily.... naturally with hills i speed up and let it ride along as much as i can...
Again taking note from previous posting I take the view that the drive is part of the holiday...
I get to my destination when i get there... why rush why worry your on HOLIDAY....
I'm travelling from Luton to Chester this week, I also blend used and new oil with the diesel as a kind of additive it's still less than a pound a litre...
Hi sir adrian, I think you'l find that your car is moving in & out of "torque converter (TC) lock-up mode, rather than changing gears.
The auto-box in Tdi 300 should actually change into 4th gear at approx 30mph.
At 52mph the TC lock-up comes into play, which in effect bypasses the torque converter and so gives more effective transmission of engine power. This is why you use less fuel at above 52mph.
When towing our horse trailer (1300kgs) or our caravan (2100kgs) I find that where possible and appropriate if I can maintain about 60mph that is a good blend of economy and keeping out of the TC lock-up zone.
On longer gradients I try to maintain about 2000-2200 rpm by using the gear selecter, going into 3, 2 etc.
Change your airfilter before setting off on holiday, it will make an mpg improvement.
Also, if not yet done, considor De-Catting your exhaust, it makes a BIG difference to available power when towing.
Cheers and enjoy your holiday.
Dave