I have a 1999 td5 with an automatic gearbox. I've just pulled a 1 ton trailer from Cornwall to south Wales. Struggling to hold 30 mph uphill, the gearbox does some strange things. I like the auto but something needs to be done. So do I swap to manual or can I do something with this bow or change to another auto box?

 

1 ton trailer is not much load, I have pulled 3+ tonnes (V8) multiple times no issues. Speed uphill is horsepower dependent so your TD5 might be the issue there. What gear were you in?

 

Gearbox just wants to change down and make the engine rev rather than let it pull.

 

Sounds like it is functioning correctly, just not enough engine power. Sorry, maybe the wastegate is stuck open? Is it building boost as it should?