I have a 2005 545i auto with about 60,000 miles.

It has developed a slight hesitation which to me feels like it is wanting to change gear then decides it doesn't want to. It will splutter for a day or two then be faultless and smooth for months, although lately it has been doing it for about a month. The splutter feels like a momentary loss of power with a slight jerk, the wife didn't even notice it happening when sat in the passenger seat but I know its there. There is no noticeable rise in engine rpms so it isn't going into neutral.

It happens when

fully up to temp,
very light throttle, only
between 1,200 rpm and 1,500 rpm, only
between 30 mph and 40 mph, only
in manual mode and auto mode, cruise control or on the right foot...

Other than this issue the transmission shifts buttery smooth

I'm fairly sure it is either a fault with the 5th to 6th gearshift or the 5th gear torque converter lock up clutch activation.

Under light throttle the 'box will be looking to shift up a gear or engage the torque converter lock up. Local indie shop took a quick look and they think engine runs perfect so it must be transmission/torque converter related, but they wanna spend some time exploring the unknown problem. No fault codes.

Again, this mystery blip hits me at about 30-40, but ONLY at light throttle. Medium or heavy acceleration, the problem does not exist.

There are no warning lights on the dash.

Anyone have any similar experiences they are willing to share to help me shed some light on this issue?

I'm thinking it may be just a software/programming issue with the box?

Or is one of the shift solenoids begining to give up the ghost?

Any thoughts would be gratefully appreciated.

Thanks!!!

 

it kinda sounds like an engine issue to me.

if you had a torque convertor issue, the rpms would change. same with gear changes, if your trans was trying to change gears, the rpms would change.

 

 

I had the same issue, dealer replaced the valve body (mechatronics) and has been gone since.

 

The notorious 30-40 slam!! Try turning the key to pos right before start and hold down the gas pedal for 25 seconds to reset the transmission. This has worked for some members. Good luck !

 

I have the exact same problem with my 2004 545i i have done alot of research and everything points to the mechatronics part kinda expensive to replace and have it fix. Its like a hiccup that you get between 35 and 40 mph after that it goes away some posts usggest a reprogram of the tranny at the dealer. I will try the tranny reset, i will let you know if it works for me.

 

Start saving for a new tranny, yours is on its way out. Or buy a warranty, BMW - Buy More Warranty.

 

I had the same thing and my SA told me that the trans was going. He is a friend so it was a heads up and not a sales pitch. You may want to see if your trans Is leaking out at all because that will expedite the failur time. I only had 70k on my trans

 

OMG. THERE GOES ANOTHER V8.... JUST LIKE ME... WHY THE HELL THEY DONT RECALL IT????? THERE IS A 10+ page BLOG on THIS.

http://www.bimmerfest.com/forums/sho...=401524&page=5

 

wow, didnt know there were so many with this issue.