Guys Ive recently bought a 99 2.9 310d LWB which has been converted into a motocross race van. It's done 230k miles but still runs lovely. I suppose theres a fair bit of weight with bike, water barrel, generator and the motorhome section. On the flat it'll cruise along at 65/70 mph all day, but when I come to a long hill i'm having to drop down the gears and work the box to keep up momentum. Some bigger hills can see it down to about 30mph in 3rd. There are no errors or warning lights on and I can hear the turbo working. Does this sound typical of these old workhorses or does it sound like there's possibly a problem?