I would tend to think that the manufacturer should NOT be liable because they pretty clearly state what they do not recommend. If you do it anyway then you are at fault.
Now the dealer has a tendancy to muddy the waters a bit because he might sell you a backhoe for a tractor that the manufacturer doesn't recommend use a backhoe, and that opens a new can of worms. Let's say the dealer installs it as says it won't void the tractor warrenty . . . FIRST, YOU BETTER HAVE THAT IN WRITING FROM THE DEALER . . .
SECOND, a dealer's promise to a customers is probably NOT binding legally back to the manufacturer so the manufacturer can probably still void the warrenty but then I would think IF YOU GOT THE DEALER IN WRITING then even a dumb lawyer could get the dealer to fix the implement and the tractor at his expense. . . .
THIRD, what if the dealer doesn't bother to say anything about the fact that the implement he is about to install on your tractor is not designed for that tractor? My bet is that YOU are then liable because you signed off on the purchase, you ordered the install, and you created a situation where there was abuse of the equipment. . .
AND if you buy and install something the manufacturer does not recommend then you are clearly at fault.
If you modify an implement in any way that is not specifically approved by the manufacturer and it fails, I'd suggest you are at fault for repairs to the implement.
If you modify an implement in any way that is not specifically approved by the manufacturer and it fails and it damages the tractor, I'd suggest you are at fault for repairs to the tractor and to the implement.
If you modify the tractor in any way that is not specifically approved by the manufacturer and it fails, then I'd suggest that they have the right to void the warrenty.
My dealer's sales rep is a real farmer full time and tractor salesman part time. He told me to go ahead and drill into the ROPS to hang some extra lights. He did not say it was approved. He just said as a farmer sometimes he has to do what he has to do to get the job done. Did I drill holes in my ROPS? NOPE. I am still toying with adding lights, but I think I'll weld them on, or clamp them on, or stick them on with magnets. Now if I lived on FLAT land, I might now worry about the ROPS but I have a lot of steep spots to deal with and consequently I wear my seatbelt everytime I get on any of my tractors, so I'm a little paranoid about a ROPS failure. But the fact is, if I weaken the structure, there is nobody to blame but me. And if I put too much load on my electrical system and it starts a fire instead of blowing a fuse, well that is my fault too.
Etcetera ad infinitum . . . /forums/images/graemlins/crazy.gif