Problems with current model Mazda BT 50s / Ford Rangers

1. My car was delivered new with first and second gear being very difficult to select. It was fixed, and then 5000 km later I lost first second and reverse gear 700 km from a Mazda dealer. [It had to be trucked in] A relative of mine has an auto and his car lost fluid from the gearbox. His also sticks in gear and shudders when changing the gears. If you have any of these warning signs [fluid loss or sticky gears]it would be wise to see your dealer.
2. My car was fitted with a canopy, racks and a wire basket. Into this basket I put a Tyre, shovel and 2.5 m square canvas canopy. [Total weight of 34 kg] Three weeks later my tub had split in 2 places. [Now 4!] Mazda are refusing warranty because they said I had too much weight on the tub sides. I have a photo of a Mitsubishi Triton with the same setup. On the racks a sticker says not to exceed 75 kg per rack- that is 150 kg all up. ARB [and possibly others?]Manufacture a strengthening frame to compensate for this vulnerability in the Mazda tub if you are to fit the sort of gear I have. Earlier Model BT 50s do not require this. There is no warning in the manual about fitting non-Mazda accessories other than to suggest that they may not do the job. Nor is there advice regarding the maximum load that may be placed on the tub walls.
I am asking if other people who may have experienced these difficulties [particularly the splitting of the tub] to contact me as I am wondering whether I have some legal redress on this issue and what others have done to address the issue. Thanks for any help you can provide. John