With the Chevrolet Colorado and GMC Canyon set to arrive in dealers in the near future, it's high time Toyota got to work on a replacement for the Tacoma , a vehicle whose present generation debuted in the middle of the Bush Administration. Now, we have images of that new pickup undergoing testing.Our spy photographers picked up this heavily modified mule undergoing tow tests in the desert. It rides on a modified version of the current Taco's frame, as evidenced by shots of its undercarriage, although our spies cite the lack of riveted sections as indications that the current truck's footprint should remain unchanged.Aside from underbody changes, this particular Tacoma featured a six-speed manual transmission, which we're expecting to be joined by a six-speed automatic. The current four- and five-speed autos found on the current truck will almost certainly be killed off. Marching to the grave with those slushboxes will be the two-door Regular Cab body style. Our spies are expecting Toyota to focus its efforts on the larger, more accessible Double Cab.Take a look up top for the heavily detailed gallery of images of the new Tacoma in action. Expect the next-gen Tacoma to arrive later in 2015, likely as a 2016 model.