In the scene at the Twin Pine Mall when Doc Brown is about to show Marty what he has built. He is controling the car by remote control; how is he able to shift the car, let alone, operate the clutch. Anyone who knows anything about transmissions, knows this is not possible. Irony, this car was offered in automatic.
I think it is safe to assume that a scientist like Doc Brown rigged the remote control to oversee all the mechanics involved to make the car shift while pressing the control for the accelerator. I mean, he DID invent time travel...
It is technically possible to shift a manual transmission without using the clutch. While it's not necessarily good for the transmission, if you rev the engine just right (with the accelerator pedal), you can change gears without using the clutch pedal.