[mega_stihl]

Hi there

As an E46 owner for over a decade, the idea of buying a 335i N54 has been in my head for a while now. Budget-wise it would be the worst decision I could think of (not only the car, but also the annual tax in my country). But I'm still keeping my eyes open in case a good deal would come by.

I've always been a manual type kind of guy. Mainly because of the driving experience and the fact that as a mechanic I know a thing or two about manuals (which almost never break down), but my knowledge on (especially modern) automatics is very limited.

If I were to own a 335i, I would go for 450-500ish hp. A turbo upgrade with FBO's would be plenty for me. Not looking for meth injection and stronger internals etc ...

My question is: how much power can these transmissions hold?
The manual is a GS6-53 if I'm not mistaken. These can also be found on the E46 330d and are proven to be very strong. Then there's the ZF 6HP21 auto. My question is: is this transmission capable of holding a lot of power? I'm asking this because most people going for higher power outputs often also change their transmission to something such as a newer 8HP70.

Also: how quickly do these transmissions react? With react I mean: if you put them in reverse, how long does it take before the gear engages? I'm asking because I sometimes find myself in a situation where I move forward, and notice "shit, there's a car or bicycle coming from around the corner which I didn't see at first. I have to back up again instantly". With a manual it's nothing more than put it in reverse and back it up, done in less than half a second. But I do know that some auto transmissions need a whole second before the reverse is engaged which annoys me a lot.

Also: how expensive is the maintenance/oil change on an auto? Is this a DIY? I've done engine rebuilds such as an M54B30, but they say modern AT's are a league of their own and you need to have the knowledge even to simply change out the oil.

Many thanks for the input!

[ptpending]

there are n54 with dct gearbox
either imported 335is from us, or european e92 e93 335 with dct

[mega_stihl]

okay, but this doesn't answer my question.

[StradaRedlands]

Anecdotally, I've never _noticed_ postings about an AT failing due to the engine having more hp. It seems like they're just basic AT that have a lot of failure points, regardless of how much hp is putting through them. I think both the GM and ZF AT are relatively robust and can handle it. The same transmission was used with the M57 torque monster motors, so probably fine.

That said, take your time and wait for a MT to come your way... if you're in no hurry, you'll find one!

[mega_stihl]

Originally Posted by StradaRedlands

Anecdotally, I've never _noticed_ postings about an AT failing due to the engine having more hp. It seems like they're just basic AT that have a lot of failure points, regardless of how much hp is putting through them. I think both the GM and ZF AT are relatively robust and can handle it. The same transmission was used with the M57 torque monster motors, so probably fine.

That said, take your time and wait for a MT to come your way... if you're in no hurry, you'll find one!

thanks for your reply

[Cloverdale]

I enjoy an 07 AT and MT 335 both modded identically to 500ish hp. The stock clutch holds the power in 1st and 2nd gear before it begins to slip. I've changed filter only, once in the auto and have had no issues. Performing your own maintenance and repairs is the only way ownership makes sense. They're incredible value in my opinion. As a daily driver I'd choose the AT.