Auto to manual conversion on 400??

Buying a stock manual transmission with the corresponding rear axle, torque tube and pedal box could be expensive, on top of the purchase cost it would probably need a complete rebuild. Last but not least the conversion will probably decrease the value of the car, as the serial numbers for auto/manuals are different.

My switch pitch conversion, which looked like a plug and play conversion, ended up as a 10k upgrade: even if the parts do fit, tuning and adjustment is labour intensive in this car, as there is so to say no room left in the transmission tunnel: even basic adjustments do require to remove the tranny, which in turn requires to move the rear axle / torque tube backward. So playing with unknown parts is probably going to make your mechanic either rich or mad...

From my personal experience: a fully rollerized TH400 with a 1800 to 2400 converter is a good match for this car (9'' converters are too small). All the Teflon shims and seals should be replaced by steel ones as they do not sustain the heat and cause premature destruction of the tranny. If money is not an issue one can add to the list the super-light gear set sold by John Kilgore (and a few others). If you swap the tranny do not forget to keep the original modulator. I am not going to pretend that this would be as fun as a manual transmission, but with a 2200 converter the colombo is a new beast and the car remains "stock".

 

Looking at earlier post you say 412 manual gearbox would be a lot easier - can you elaborate. I might be able to source one.

 

I'll certainly tip my hat to anyone who can successfully pull this conversion off.

 

I meant easier to operate, the clutch of the 365 and early 400 requires a ton (actually 16kg?) of pressure in order to disengage the disc. The pressure on the left leg is so important that the rest of the body slightly tilt. As a result I can hardly keep the steering wheel straight when changing gears on the 365. Did not have such issue with a 400i gen2. None of these car are mine, so I did not have the opportunity to inspect the actual differences under the bonnet, but the later transmissions felt better. Same story regarding auto transmissions the later ones (shorter rear axle and better converter) are much better. So i would definitively look for a more recent transmission.

Pease note that 1) I am only 65kg, so probably that a more muscular driver would not mind the 16kg pressure, 2) I've only test driven a few of these cars so maybe the discrepancies were related to the conditions of the cars.

In any case the auto to manual conversion is going to be quite a challenge regardless of clutch used... As said earlier, the motor, the transmission, the torque tube and the rear axle are to be considered as a "rigid" setup, adding or removing items in between is not going to be easy.

 

Maybe I missed something but wouldn't it just be easier and far less expensive to just get a manual car? These are rare cars but with time one will come up for sale that has a manual.

 

Not sure you missed a thing Jim. I’ve always thought the same. There aren’t many, but they do appear for sale now and then.

 

It took me a couple of years to find mine.

 

+1

 

I know where there is an empty 400 manual gearbox case and empty torque tube if that might help.

 

Thanks for the detail make st helpful.

 

Yes would be easier but we have auto that we have as base for project. So too late.
Suits us to convert it but only gearbox we can source is 412. Everything I read says it will fit onto 400 but none can give me 100% confirmation. Anyone out there know. It all looks right

 

It should be close enough, at least minor differences a machinist can easily fix. The speedo is different between 412 and 400 gen1, could be electronic (?), not sure though.

You would have to buy a detailed wiring diagram as there are provisions for auto/manual cabling, so no need to butcher the existing harness!

 

If this wasn’t solved in 2007 or 2013, I doubt we’re any closer in 2019.

Matt

 

There have been lots of people who’ve talked about it over the years Matt, but not one success story.

 

I know.

Take a look when this thread was started.

Matt

 

Rear diff ratio.
Auto 3.0/1
Manual 4.3/1

 

The ratio on auto is 3,25:1 (12x39). I have used the 400GT on long trips through Europe a couple of times. I sure miss a 6th gear or a different rear ratio. At one point I considered the auto rear axle but that would be ridicilous - would never have got to 5th gear under any normal circumstances...

 

I did it for 22547 and had all of the correct parts for another conversion. I sold all of the bits (as a package) last year.

If you don't have ALL of the correct parts before you start, my suggestion is that, rather than undertake a major project like this, join AA (Automatics Anonymous) and get a life!

A couple of things to consider at the start;

Torque tube - If you go for an open tailshaft you will need new diff mounts, gearbox cross member and engine mounts to counter the torque reaction. The extra movement will create issues with the oil and water hoses and more important, the K-Jetronic bits stuffed in around the engine.

Clutch actuation - Take a look on the parts diagram for the pedal box. There are a lot of extra bits required to mimic the original cable actuation. Using a LHD gearbox in a RHD car (or vice versa) will present lots of challenges routing the clutch cable.

Of course you can do anything if you throw enough money at it.

Regards

WM

 

Very cool!

Matt

 

If you don't mind me asking; What year did you do this? Any idea of the total cost?

 

The parts were gathered over a few years and the car finished in 2015. The cost for the manual conversion parts was around 10KUSD but that was when F parts were much cheaper and easier to get. They would probably be a lot more expensive these days (if you can find them).

The smaller but still necessary parts are hardest to find or make. You also burn a lot of hours figuring out details, measuring things and reconditioning parts.

Regards

WM

 

Yeah, I’m betting if you could find the parts it would run you at least double that now.
The current market looks like a 5-speed is bringing between a 35% to 50% premium over an automatic.

 

Ok now on the hunt for sports had my foot on 412 gearbox but it fell through . If anyone can point in the right direction would be great. Have tried all the usual suspects.

 

Maybe helpful are they still around ?

 

Does anyone know where to obtain a 400/412 manual trans flywheel?