[Boolin N Juulin]

bought a used 07 335i (late 06 production November i believe)
its a complete lemon
20 different HIDDEN fault codes within a month after FINALLY hooking it up to an autel diagnostic machine
i started getting "yellow cog of death" as one with the fault readin 4f8d ... this was discovered AFTER i saw a code for P17EC and the description was "Gearshift monitoring 5-4 downshift" or something like that
i never had CRAZY issues until it reached optimal temp and id hit the brakes without allowing a proper downshift now the car is in full on failsafe mode with the yellow cog always on the display whther the cars been on or off for hours... i can hear the tranny just straining its ass off...
i found out its gen 1 tranny so i decided if im stuck paying for a new one id just swap it with an 08-09 tranny but as i went to purchase said tranny i was told it wasnt compatible and after making calls to bmw and an indy shop they said that its impossible to "swap" tranny's because theyre burned to a specific car? can anyone help me please

[IllSic_Design]

It's possible, people swap from Auto to manual and also people have swapped to DCT(dual clutch trans), it just requires the car to be coded for the new transmission. Going ZF to ZF I'm not even sure if you would need to code anything?

[MysticRob]

Get it diagnosed properly at a dealership, and maybe read this.

https://www.e90post.com/forums/showthread.php?t=1036295

[Boolin N Juulin]

Originally Posted by IllSic_Design

It's possible, people swap from Auto to manual and also people have swapped to DCT(dual clutch trans), it just requires the car to be coded for the new transmission. Going ZF to ZF I'm not even sure if you would need to code anything?

everyone ive talked to says id need a whole new mechatronic and/or tcm? is this the case as far as you know?

[Boolin N Juulin]

Originally Posted by MysticRob

Get it diagnosed properly at a dealership, and maybe read this.

https://www.e90post.com/forums/showthread.php?t=1036295

i plan on taking it to bmw if its not too much i believe they said like 150 for diagnosis
but i was just wondering bc now Sandia BMW in NM said that you actaully DONT need to code anything for tranny just the engines because i dont have an "I" system or "higher end" bmw
while another indy shop said you do in fact need a new mechatronic and to code it bc they're "burned" to the VIN

do you know if either is true?

[MysticRob]

Originally Posted by Boolin N Juulin

i plan on taking it to bmw if its not too much i believe they said like 150 for diagnosis
but i was just wondering bc now Sandia BMW in NM said that you actaully DONT need to code anything for tranny just the engines because i dont have an "I" system or "higher end" bmw
while another indy shop said you do in fact need a new mechatronic and to code it bc they're "burned" to the VIN

do you know if either is true?

I have no clue unfortunately. I'd default to reading up on everything you can on this code and bringing it to the dealership to guide them if they're not already aware of the typical solution.
BTW, do you have the ZF or the GM transmission in it? I thought I'd read some of the early cars had GMs, but maybe not in the 335i. Figured I'd ask for my own amusement since I don't know what you meant by 'gen 1' tranny above.