Year...near impossible. But post a picture and I can tell you really quick. The shell color will tell you very little since you can put any body on it that you want to as long as it will fit. There were three/four basic versions of the T-maxx. The .15 original. It had a .25 engine with a rotory carb and the shorter a-arms. The tranny and battery/receiver boxs were black plastic. The next was the 2.5 Maxx...as a .15 engine but had a higher power output. This had a slide style carb and a gray/silver head on the engine. The 2.5 had longer arms changed up linkages and is now a rear exhaust engine vs. the side exhaust on the .15. The tranny and battery/receiver boxs were still black plastic. They also had the 2.5R with had a slightly differnt engine still a 2.5/2.5 engine but had a blue anno head on it. The tranny and battery/receiver boxes are now gray plastic. They then came out with the 3.3 version of the T-Maxx it as had the gray plastic but had the 3.3 engine. The chassis was also lengthened out in the front by about an inch and gave a Revo spec drive line, brakes ect. That is a basic cliff notes run down.