Cheers Rod.
I drove the same route back in september. But i had stock wheels and tyres and had no roof rack. I also didn't have the gauges, so have no clue what temps were doing and yeah it was fine with those hills. However, it's Different now ...

As I said, I'm not after nor do I expect super power from it. I am 90% positive I won't be towing a caravan or camper trailer or anything for many years to come . I'd just like to have it running "right" . If that makes sense. I'm happy to drive it around like a truck chugging along...
But yeah, after this weekend gone I need to do something...

Matt, it never ever crossed my mind about the diffs. I will do some reading as I'm fairly naive when it comes to that. Cheers.