Hi guys. First, it looks like I'm going to have an excellent "Advisory Council" for this project. I hope you guys will be patient if it sometimes takes me a few days to get back to this thread, but that will usually mean that I'm still researching. Right now I'm looking at differentials and I'm trying to figure out the difference between the 5608 and the 5379. This is all new to me so it will take me a little while to get in the groove. I like the differential that you posted the link to R.C., and if you can confirm that that's really the one that I want I'll order it today. No offense meant and I'm not doubting your recommendation, I'm just not sure if you sent that link as an example or if you think it's the exact piece that I should get. I also like your idea of starting with the differential and taking one step at a time. Once I order the differential I'll start the pre-assembly and get everything laid out and see if I can duplicate that track tensioning system and by the time I get that done the differential should be here and I can look at mounting that. I think that will be the time to look at the parts that Brett recommended and see if we need them. I don't think I'm going to try and do a suspension for the tracks. Maybe later when I get much more experience I might be able to go back and revisit that but for now I want to take the easiest possible route to get to the end product and learn as much as I can along the way. Oh yeah, if I use the planetary gearbox will I still need a transmission like the R2? And if anyone knows of better aftermarket tracks and can post a link to them that would be seriously cool. So thanks again guys, and I'll post photos soon of my progress. I usually get most of my work done on the weekends so I won't be doing much during the week. The job kind of takes it out of me and by the time I get home at night I'm ready to watch a little TV on the couch with the cats and rack out. I'm sure you guys all know the feeling.