Cobra4B

Modifying my GMC Canyon to tow the Z... installed a deep well bed box this weekend.

Had to install a bed box reinforcement kit from GM to alleviate any possibility of distorting the bed corner joints w/ heavy loads in the box. There is a TSB out from GM on the issue.

After mesing with the bed drilling, hammering, etc I can see why GM made these.... the joint between the bed side and the bed front is rather weak and you can almost shake it by hand.

The brackets... they come painted black from GM


Test fit on the truck


Measure twice, mark, and drill away!



I got spray in bedliner in a can to re-cover the bare metal from drilling... don't want to give rust a chance!



Being ****... I decided to prep, sand, and spray the brackets eventhough they're most all covered.


Didn't take enough pics of the hardware... but you install the brackets and bolt into place... bed joint is completely sturdy now.


Decided to mount the box w/ the Deflectashield mount kit that's far more robust that the crapp "J" bolts it comes with... it was $11 from Advanced. I laid the supplied foam down over the brackets and covered the bolt heads that stuck out alont the bed front part so the bed box had nothing to clink against.

All done! Pulled the logo on the box off for a cleaner look.



Next up ready to install: auxillary trans cooler, air lift helper springs, Prodigy brake controller, and 7-pin harness upgrade.

John Shiels

looks great hows the spray on liner seem? How much did you use? I am always painting my truck where the liner rubs near the end of the bed. I have a rust phobia

Cobra4B

Well I had Rhino Liner sprayed in the entire bed which is awesome... I was going to get rustoleum paint to paint the drilled out holes, but then I saw teh bed liner in a can! It covered the drilled holes w/ ease and the color/texture does a good job when on top of the Rhino Liner, but those areas are covered anyway.

The actual brackets didn't wrinkle up as much as the Rhino Liner... it's a nice tough finish, but it's definately not the same quality as The Rhino Liner.

Restorod '79

That's a nice looking little truck! You'll want to have a tranny temp gauge somewhere in the works. A tee in the soft cooler lines can work nicely for this. If you're under warranty, don't open your pan and change it! (I'm assuming auto trans.) I just did that and the dealer through the red flag on the mechanic who was to replace my trans.
I ended up getting a good built tranny, deep pan, aux cooler and gauge. I've got a modded 5.3 liter that will cook a stock 4L60E in one outting!
Pay attention to your weights, ie trailer, car, tools and equip. Get your speed fix at the track, and tow slow. It feels good to tow it home in one piece! Good luck and have fun!!

Cobra4B

Thanks... I hadn't planned on messing w/ a gauge but I guess it won't hurt to do it right.

What do you mean about the pan? Are you saying don't put an aftermarket pan on it?

Yes... I will be very **** about proper weighting of the truck etc and will get a load distribution hitch if needed.

Restorod '79

I'm freshly sore about trying to make improvements to an incapable GM tranny, and then being told that I "tampered" with it, so they would not warranty it;'s failure. As far as a pan goes, it's my understanding that by adding a deep pan(+3 qt.) made of aluminum and finned for cooling, you will prolong the life. I'm just cautioning you not to do it yourself. Your dealer may be more the kind to appreciate mods. Mine is not. Mine is history! They loaded all the pieces of my truck, drivetrain, transfer case, tranny, brackets,etc into the back of the truck and pushed it out of the dealership. I had it towed to a small tranny shop, an X-modified racer who knows how to build a tough unit.

I'm simply hoping that no one ever has to go through what I did. If the dealership installs your pan, or gauge, or cooler, then you might have better luck with warranty issues. I don't know for sure. I'm a do-it-yourselfer and I own this truck now. And it ROCKS!

Cobra4B

If the trans goes out... I'll idsconnect and remove the cooler, then install a soft line and take it in.