I actually did all of the leg work on this guy over a year ago, but had so much going on that I shelved the project and get back on it until now. For the hips, I borrowed Ptitvite's idea of using the Energon Sledge hip/crotch and hip ball joints. I did change up the idea just a bit though to make it a bit different from his. I used the upper legs from a Universe Octane/Tankor junker. I cut those to size, then glued them to the ball jointed hip section from Sledge. I then attached that entire piece to the existing G1 hip/crotch section (minus the original G1 flip-out hips). I cut a bit on the back of the G1 Sludge legs to allow them to fold in and glued the knee of Octane to the existing G1 Sludge knee hinge (the black piece). The legs fold in perfect for dino mode, but you have to bend the knees just a bit (which is great, because they are now basically double-jointed due to the joints from Octane and the original Sludge joint). Picking this up a year later, I hit the shoulder areas to ball joint those. I did hit a snag though and found that the bot mode "wings" wouldn't fold over the shoulder with the new ball joints in place. I thought it over for a couple of days and remembered a junker Acid Storm I had used for scrap parts (got another crazy project I'm using parts from him on that I haven't shared or told anyone about yet--it's probably another year-long project to do in between the others). Anyway, I snagged the Acid Storm shoulder hinges, cut them to size, and glued them in. I then used one of those TFTM '07 real gear watches (used some ball joints and shoulder parts for Slag--have no clue what the sucker's name was)......I cut down the two shoulder joints and cut out a space in the G1 Sludge shoulders for them to fit in. I had to add some square styrene rods (two small pieces, one each) to the shoulders, then glued the ball joint in place on it. This allowed the joint to stick out a bit and allow the shoulders to rotate and move around better. I then hacked up the G1 forearms (keeping the hands in place) and cut parts from the Sludge arms to fit onto it (the "claws"). I then used the elbow joints from the TFTM '07 real gear watch to articulate Sludge's arms more. I also cut the tiny post that allowed the real gear arms to snap into the shoulders originally, then worked it into the Sludge arms so that he now has ball joint rotation at the shoulders, the post swivel rotation at the top of the biceps area, the elbow movement and the flip out hands. It's basically just a frankenstein of parts there. Now the shoulders can flip up on the old Acid Storm hinges, the arms can rotate toward his back on the ball joints, and the "wings" can fold over to become the sides of the dino mode. I also ball jointed his head a year ago--it fits nice and tight right between the two posts on the "wings" that the dino head and neck fold down on and snap into. The waist also still rotates to give hip articulation. The only thing left to do is to extend either the upper part of the back dino mode legs OR the foot area on those rear dino legs. The front legs are a bit longer now due to the added articulation (and I always hated how those forearms folded underneath in dino mode originally). I'm basically doing something similar to what Ptitvite, Jaf, and Mike did with their respective Sludge works.