hi i have just came back from a caravan holiday with my 4.4 03 lpg converted rangerover towing a large 4 wheel caravan 2 tonnes hardly new it was there my car went into 3rd gear lock arount 20 miles into journey would not change up did not get trans overheat message and had to drive 80 miles in 3rd gear kept her to 50 /3000 revs no rise in temp no funny noises just realy annoying and used more fuel after unhitching caravan transmission returned to normal changed gear no probs she seems to just do this when towing started when going uphill changing from 4th to 3rd up and down until trans lock anyone any ideas 