400i Replacement Automatic vs. 5-Gear-Box

I looked at it - it's a big job

 

Flywheel, clutch, pedal box, gearbox, diff centre, centre console... and then all the little things that only become evident when you try to put it all in - nuts, bolts, spacers, etc, etc.
And when you're finished, you'll have a bitzer car that isn't real, and doesn't match its spec.

 

What you need to take into consideration is the transmission's roll is not just a transmission on this application. It doesn't have a transmission support (it has a reaction rod) and this is because it relies on the engine mounts, torque tube and rear differential mounts to support it. This is why the 400 manual trans is iron not aluminum and in auto-form they use a tank of a transmission being the TH400. So chose a manual trans with that in mind, I personally would use a T56 6 speed and make a crown gear set in a ratio that works well with the ratios of that transmission. Or put a 550 gearbox in it out back assuming it fits the space, now wouldn't that be interesting. Might be able to use the 550 or 456 bellhousing, torque tube set up too.

 

The T56 is found in vipers, vettes, mustangs, camaros etc. I would find a used one paying attention to the forward gear ratios.

 

The transmission tunnel is huge so I would think it should fit.

 

Has anyone ever done a transmission swap on one of these? I have never seen pictures of a swap, would be interesting to know if it has been done. I think it could be but would be very difficult.

 

"Very difficult" is probably understatement. The burnt out shell of a 400 carcass for sale in this thread would be right level of car to do this with. On anything reasonably complete, the work to make it right would be insane.

As an example: A friend had his 400's engine stolen while it was out of the car years ago.

The car was totaled and some time later the engine was found. I met the guy who bought the car and engine--still unassembled--who was going to try to put it back together. He would come over an look at my car, take pictures of how things were supposed to go together. We talked over a year period before I lost track of him. To my knowledge that car still does not run. The small and unique parts are the ones that get you on a 400i.