Manual to Auto Gearbox change(?)

The manual gearbox on my 2014 F36 420d x drive needs replacing and before I start searching for a replacement I was wondering if I could replace it with a Steptronic transmission? I've had various BMW models in the past 20 years and I like the Steptronic. Is it possible? Easy? Hard? Costly?

Any advice would be appreciated

Thanks

Paul

 

Costly, you would need:

The gearbox, gear selector, cooling pipes, probably a new oil filter housing as I think the gearbox oil cooler is located in the vicinity. Different prop shaft most likely, probably new front and rear diffs (ratios are different to manuals), associated wiring and coding. Would it be worth it? Easier and cheaper to trade it in.

 

New ECU for the gearbox.

 

Isn't the gearbox ecu in the gearbox itself? I always thought so, but never found out for definite.

 

A good point. It would need cloning to the car ECU though, not sure that could be done? Some rewriting of both ECUs for sure.

 

Are the diff ratios the same ? - the exhaust may be different, the engine may be mapped different to suit the gearbox, stop start system may not work correctly, pedal set up will be different ....the list goes on...

 

And the crankshaft is different, flywheel, ...

 

The crankshaft won't be different, flywheel will be.

 

This

 

Dave
You sound like you’re up for this job..!!



Sent from my iPhone using Tapatalk

 

Try realoem. Different part numbers. I'm guessing attachment of clutch vs tc.

 

The torque converter bolts to the flywheel. Different part numbers are used even if there are only minor updates. Even if a part is then provided by a new supplier. Also, if the crankshafts varied between auto and manual then realoem would list it on the appropriate page. It's the flywheels that are different and they are listed separately

It's all moot anyway unless the op will be going ahead with the conversion

 

The flywheels are totally different between auto and manual, auto is just like a metal plate whereas manual is dual mass, a couple of inches thick and the clutch plate actually contacts it.

OP in reality it would probably be cheaper and far easier to buy a 420d auto and keep the manual as well than it would to convert it.

 

Yes I know the flywheels are different. My point is that the crankshaft will be the same.

 

Working from the front back, it becomes evident it’s not a financially viable option as mentioned previously
Oil cooler & thermostat, pipe work, Starter motor, torque converter, gearbox, mounting plate, oil, interior trim, lever, pedal set, wiring harness, ECU coding then the necessary VOSA reclassification and tax liability (often neglected though req’d)
Whilst a manual box will be Circa £500-£1600 + fitting (clutch if required) it’s the cheaper option to replace, sell and purchase a car with a factory auto box....
Gone are the Auld days where the Granada’s and Cortina's could be converted on a Sunday afternoon