Boost7

Anyone else with a 545 have an issue with their transmission hunting different gears if traveling steadily from 30-40miles? If I keep the gas steady around 30 or 40 miles, I can feel the transmission trying to hunt for the right gear, and it'll do it back and forth. I can feel the car jerk, and hear a thump. I try watching the rpm, but that doesn't change, but I can feel the car jerking when it happens. So I'm wondering, if my transmission is going bad, or is there a software update that can help fix this. Otherwise the car drives fine from a dead stop to highway speeds.

aharper

My car did something similar. At about that speed staying steady the rpm's would rise and fall slightly and the car would feel like it was changing gears. It would make the "adjustments" within about a half second and then go back to driving "normal." It would stay normal for about 15 seconds and then do it again. I never could figure the problem out. Seemed I had a bunch of small things like that that were difficult to replicate and I finally got tired of taking it to the shop for repairs (and I had an after market warranty).

rrnag30

this is a common issue actually. Do a search for mechatronic issue / transmission surge/hiccup.

https://5series.net/forums/topic/116...l__mechatronic

https://5series.net/forums/topic/791..._1#entry911288

https://5series.net/forums/topic/769...smission-slam/

jaycal3

I have the same car and experienced the same issue... not often but on a couple occasions... I dont care what anyone says about the transmission 25 second reset procedure, I did it and havent experienced the same issue in months. Try it - it cant hurt.

Put the key in and turn it 2 positions without starting the car... hold the gas pedal down for 25 seconds and then release it and turn the car off. Then start the car and go for a drive... maybe you will have the same success I did. Some claim its only snake oil and others swear by it. Like I said, it worked for me - and I am certainly not imagining that!

Boost7

rrnag30 - Thanks for your reply, the second thread with Cobra 427 is exactly what I'm experiencing.

jaycal3 - I tried the reset already, but it didn't help. It was worth a shot. So it sounds like I might need a new mechtronic module. Does anyone know how much these modules run, with labor? My car is used and out of warranty...FAWK!!!

saltdog

I had the same issue at 68k miles. After replacing the transmission fluid in my garage the problem has not come back. It shifts extremely smooth now with no hesitation. Many people take it to BMW where they're told it's normal. BMW will also tell you the transmission fluid is a lifetime fluid. I don't agree with that because when I drained the fluid it was completely black.

AchtungE60

LOL right? Their lifetime is 100K miles. So I changed at 98K miles and my fluid was very dark. I changed all 9 liters, pan, filter. Please do a search on your specific tranny and a DIY with correct fluids for your tranny. IF you take it somewhere make sure they treat the car like its theirs and follow the manufacturers specifications on drain/fill/fluids.

automedic

HI I HAD SAME ISSUE WITH MY 05 545 TRANNY
i JUST RESET THE TRANNY WITH MODIS THERE IS A FUNNTION RELEARN TRANNAY AFTER THAT THE ISUUE WAS GONE.
NOW i PAY ATTENTION THIS PROBLEM COMING BACK BUT SO FAR SO GOOD FOR 5 DAYS, EVERY DAY I DRIVE MINE ABOUT 23-30 MILES.
GOOD LUCK GUYS

jaycal3

Ouch... my head hurts now.... I think your computer is broken! Everything seems to be yelling

Boost7

So I'm adding to what I've found after driving in manual mode - I guess this is sport mode keeping the engine at a higher rpm. I notice the 30 or 40 hunt isn't there. The jerky hesitation when coming to a stop isn't there also. So my question is, does this sound more like a software issue?

Someone more familiar with the difference of normal setting and sport/manual setting on these transmission, please chime in.