[This tutorial is for] Classics Prime. It's pretty easy, and you only need to cut or Dremel a few pieces in order to do it. Here's what I did, and the tools I used:

Tools

Dremel
Soldering Iron
Super Glue

How To (w/pics, thanks to tfkenkon.com)

1) Transform Classics Prime into bot mode.

2) Using your soldering iron, heat the pin that holds the door onto the arm flap (the small flat pin that is embedded into the rounded part of the door hinge). This is marked in green on the picture

3) Repeat on both arms . . . the doors should now pop off, leaving the rounded hinge piece still attached to the main door/arm hinge. This is marked in green on the picture

4) Transform Prime's arms as you normally would, wrapping the hinged parts around the backside of the forearm and you should now have the rounded hinged part on the side of the forearm.

5) Take the doors you removed, and, on the insides, you'll see a clear blue tab sticking out (just above the side windows). Cut these off (flush against the rest). This is marked in yellow on the picture. You also need to cut off the entire rounded hinged piece that still remains attached to the doors themselves. This will allow the doors to swing up and into place in alt mode, once you have the pieces glued into place later. This is marked in green on the picture - cut and removed the hinge and clear blue parts that hold the hinge on the door - but leave the rounded hinge area that is still attached to the bot arms.

6) Now look at the front grill of the truck in bot mode. You'll see two tabs that stick off to the sides of the grill. These need to be cut off flush with the sides of the grill (these are the two tabs that the door/arm pieces used to "snap" into). This is marked in red on the picture

7) You'll need to attach the front ends of the truck to the truck bumper using super glue (the door/arm pieces you removed earlier). This is marked in blue on the picture

8) Let the glue dry, then transform into alt mode. Be sure to fold the bumper down fully on Prime's back to allow his arms and chest to swivel around. Transform the arms as you normally would. Now flip the bumper up and it should easily slide into place and look factory (like you never altered it or modded it.

This does give Prime a bit of a backpack, but you can fold the bumper up, which allows the door parts to sit close to the back. It gives a MUCH better look for the bot mode and the alt mode is unchanged. Hopefully you get the idea from this picture and the areas I circled to help show where to do the mods.

These pictures should help you see the parts I cut and how it all fits together (along with a sort-of transformation sequence with the new mods). Also, keep in mind that my Classics Prime is still a work in progress and he still needs to be painted (I did detail the insides of the cab and line the windows in silver - the red and blue you see was basically a test to see if I liked those shades for him . . . the blue will be darker on the final version):

 

[Here I'm] just adding to the festivities with a pictorial walk-through. Most of the info's redundant, but [there are] a few differences and add-ons that might make it worthwhile.

The big difference between my set up and hXcpunk23's is that, rather than trimming the grill tabs off to accommodate the door panels, I trim the door panels to accommodate those grill tabs. The reasoning for this is simple: I'm accident-prone and take every opportunity I get to idiot-proof my work. Leaving the tabs in place gives another place to check the placement of the panels in relation to the alt mode.

That's not to say my decision is the better one. Clear plastic is generally harder and more brittle than solid plastic. This means that not only is it more difficult to cut, but, especially when dealing with the $12 KOs, more prone to cracking under stress. Weigh the benefits and downfalls and make the decision you're most comfortable with.

The rest is just reinforcing the mod to handle the stress of transformation. I've had a panel snap off once or twice from handling, so anything to help the super glue will be of use here. Also a random bit about the holes left on Prime's arms.

So yeah, a few weeks later than I intended, but hopefully better late than never!
















No, that wasn't a typo. It is important to test the fit before you glue, and even more so WHILE THE GLUE IS SETTING. It'll be a pain to snap the piece off and try again, especially if you're dealing with brittle KO clear plastic.