Hey y'all. I have an LCI e60 550i with the Sport automatic transmission 6hp28 (6hp26TU per BMW part diagrams). The transmission has 91K miles on it, but I'm experiencing many annoying problems. I'll try to list as many as I can:

• Metallic grinding noise (like shaking a bunch of coins in a cup) when accelerating at below 1 to ~1.7K RPM.
• Severe, rapid jerking/lurching when coasting in 3rd/4th gear from below 2K rpm. So bad that the tach needle bounces around and sometimes the car feels like it's about to stall. It is worst when the transmission is cold and goes down after 15 min of driving, but is still there at a lesser intensity.
• For some reason, it wants to shift out of 3rd gear ASAP. It'll shift into it and immediately shift into 4th. This keeps RPMs below to about 1K when driving gently.
• Always tries to keep RPMs at or below 1K and it almost feels like the engine is lugging every time. I really have to push the gas to get it to upshift.
• Especially in sport mode (button), using manual mode, shifts are usually fast on both upshifts/downshifts, but sometimes around the 3/4/5 gear range upshifts are slow and spongy. Sometimes even all the gears.
• In sport mode again, sometimes takeoffs from lower gears don't feel direct. Usually they are, but 50% of the time it feels like power is being transferred thru a sponge, almost like the TC isn't locking up at all. The engine also seems slow in acceleration during this.
• Very (I think) typical slipping under even light acceleration. RPMs will go up, then down, then slowly rise up before the car actually gains speed.
• The slipping gets worse under heavier acceleration. The transmission also seems to hesitate and decide what gear to move into before the slipping occurs.
• Just yesterday, the same lurching as in bullet 2 happened, but instead of while coasting it was while accelerating. The tach bounced again (near 2.6K rpm) before the downshift was performed and the car actually sped up.
• Recently, I heard and felt a very prominent "bang" while accelerating out of a U-turn. The same lurching as in the last bullet point happened too. That was the worst "bang" so far; there have been a few since then but not as bad.
• Not as bad as the other points, but sometimes shifts into some gears seem hard for no reason.

Sorry for the massive wall of text. I was wondering if it's even worth doing things like a fluid change or replacing solenoids or something else. Or should I just look for a replacement?

 

I am no expert here. I own a 2004 E60 which had trans issues with multiple faults and going into limp mode after a moderate or vigorous acceleration. Fluid change was no help. Was advised a mechatronic unit sleeve/gasket change. I skipped that and had the trans taken out and given out to a trans rebuilder. There were multiple things wrong in the trans that needed a full rebuild. (in retrospect the VB fix would not have solved the issues). Now the car drives perfectly well.
I am sure a reputable shop can pull codes for you. Before you go piecemeal swapping out parts, assess if you likely possibly need a full transmission rebuild. I am sure the more experienced members here will chime in to with their more experienced opinions. Good luck. Keep up updated on what happens.

 

Did you ever get this resolved? it sounts like your metatronic unit needs either rebuilding, or you need to service your transmission, replace all the solenoids and the sleeves, trans fluid etc...its a lengthy process and you will need INPA or ISDA software to proplerly service and refill your transmission fluid. I did it on my 2008 550i and it runs like brand new..even reset the adaptations.

 

Thanks for the replies. I have not gotten this fixed yet, as I'm still trying to decide what to do. I don't want to go through the process of a full mechatronic rebuild just to have the same problems due to internal damage. Cost is another factor too.