Just to let you know, it is possible to mount the older T-maxx tranny on the Gmaxx chassis, but as you discovered the newer style Revo tranny is a slightly different shape/mounting pattern I believe. Having mech brakes on the G2r would be rather nice, since you could run a plane esc and some really high voltage electronics setups without the fear of only having a handbrake to slow the truck down, lol.
Well, heres an update . I have a ofna hyper pro spider center diff on the way . So, I will have to wait till it gets here to polish these up or remake them altogether lol . Heres some pics from todays project .