Aston Martin just announced that it will be building a Vantage AMR that will feature the twin-turbo 4.0-liter V-8 backed by a Graziano seven-speed manual transaxle. The V-8 is shared with Mercedes-Benz and found in vehicles such as the AMG GT. Naturally, some have wondered whether this could open up the possibility of an AMG GT with a manual transaxle. We dug through some diagrams to find out.
Along with the 4.0-liter V-8, the Aston Martin Vantage also shares a powertrain layout with the AMG GT with the V-8 mounted up front and connected via a torque tube to a transaxle mounted in the rear. Those details would make it seem like it would be easy enough to replicate manual swap in the AMG GT but the two cars are a bit different once you look underneath the surface.
The Getrag 7DCL750 gearbox used in the AMG GT is actually a fairly good match to the Graziano unit in the Vantage when it comes to gear ratios as they have a similar first gear ratio with the rest of the ratios being a few hundredths off from each other. (Automatic transmission Vantage models use a ZF eight-speed, not the Getrag.) Even though they are a good match ratio-wise, the dimensions and arrangement of the Getrag auto and the Graziano manual are very different. The Vantage has a much larger tunnel opening for the torque tube and puts the transaxle closer to the front of the car with the axles exiting at the very rear of the unit.
On the other hand the AMG GT, with its shorter wheelbase, pushes the transaxle back with the axles exiting closer to the front of the unit. Due to this arrangement, the Graziano unit could not be installed into the AMG GT as is because the front three quarters of the case would interfere with the floorpan in the vehicle. This could possibly be modified but it would likely require a complete redesign of the chassis and rearranging of the surrounding components.
All of these changes would also likely require new crash testing which would make it even less feasible at this point as Mercedes-Benz is already deep into development of the next generation C192 AMG GT. The next generation car is also unlikely to get the manual Graziano unit. Rumors and spy shots have shown that the next AMG GT is likely to have all-wheel drive which would put the Graziano unit out of contention.
Considering all of the points, the manual-transmission AMG GT is unlikely to exist outside of some enterprising tuning house deciding to modify an existing car. If that happens, we’d be interested to know see how it gets done.