I am wanting to build my own draw system for th back of the nav and i have seen heaps of desgins but i dnt no how people secure them in the tray. Do they drill holes in the tray and bole them in or what?
In mine (D40) I made up some metal blocks then cut a thread into them and put them into the channels on the floor and bolted to the rails of my sliding bed so they work similar to the factory cleat system. (If that makes sense).
I used the existing bolt down points used to bolt the channel onto the tray. Worked a treat. Although, in hindsight, JPMC's idea is a far better alternative.
You can use low profile bolts with large washers and slide them into the existing utili track system. or cut a rectangular washer and tack or weld a threaded rod through it. I did the later and used a 2nd hand set of ORS drawers bought on ebay. It fits great and you can easily adjust the position of the drawers in the tray (forward or back) if necessary.
If you no longer need your Nissan cleats you could use the bolts and cut/thread down to size.
I have a couple of bits of light angle that drill into the top of the draw system and then into the rear of the tub and the side ones drill into the bottom of the tub.I just used self tapping screws.