Transmission Issue
 

Hey folks,

I have '12 X5 3.5i that I got back in February and have this weird thing going on that even got the BMW dealer here stunned with it.
Here's what's going on: Car is fine when cold in the morning - upshifting and downshifting is like it's designed to work. Then it reaches a point where the issue I have is showing up when i get in stop-and-go traffic after the car has been driven for at least 30min.(sometimes it takes less if warmer outside, or longer on colder days). When slowing down to a stop, after the transmission has shifted up to 3rd or 4th gear, there i this violent shudder the RPM's drop to about 500 and immediately go up to 900 for about 2-3 seconds before it eventually evens out to 600rpm. When still at dead stop and when I release the brake, it feels like only in that moment the transmission finds the right gear to start going again. On occasions, the RPM's fluctuate up and down with about 100 in between. Here's a link to the video of what's going on.

https://www.youtube.com/watch?v=fY7BYJwI9vI

I had the car at the dealer for about 5 days and they performed the software flash update, but after the issue showed up again gave me the b.s. crap they couldn't figure it out and asked me to approve an amount to start replacing parts.
I just replaced the tranny fluid and filter, but yet no luck.

I hope one of you folks can help or give me an idea what this may be related to!

Sadly, dealers are horrifically bad at diagnosing and repairing anything transmission related.

Or anything car related :yikes:

No warranty?

Feels like new transmission time.

UNLESS you take it to a shop that will open up the trans and get after the valve body- flush it, clean, refresh seals.

IMO when the AT fluid gets hot it thins (lower viscosity) and the transmission is then no longer is generating proper pressures to move actuators, etc around.

BMW dealers do not open transmissions...

Find a shop that can work on transmissions, that ONLY works on transmissions.

I cannot recommend this more strongly- I am convinced that we will see more and more E70 trans issues and we have little to no knowledge on how to fix these internals. (I will add that as a wife-driven car, who likely has never pressed on the skinny pedal hard enough to cause a downshift, **I** will not one of these trailblazers... ;) )

^ yep

My opinion. I'm not sure this is a trans issue. If the symptoms disappeared for a few days, would that happen with a mechanical trans issue? When the car is slowing to a stop, the rpms bump up slightly with every downshift, which looks normal, and under brisk acceleration, the shifts look crisp. I'd get another diag from a different dealer, or a known competent independent shop.

Ard - All of these are very good points. No Warranty left on the vehicle for it's at 53000. This is very weird issue for the fact that it does the same thing when engine at transmission are at operating temperature and at parked car you put the selector on D or R, it will do the same shuttering dropping the RPM's. Someone suggested it may be the clutch, but in this case the vehicle is at a dead stop. If you raise the RPM's to 1000 and then shift between D-N-R, the shuttering goes away. Dealer here investigated some vacuum leaks and said they found one and repaired it, so I'm more inclined to go that direction like davidmaria1 suggested.
I took the car to an indy shop and they were not sure what was going on, but were convinced it was not the tranny. I am thinking I need a 3rd opinion.

Search for BMW goodwill. The dealer has the ability, in some cases, to cover issues just outside warranty.

The transmission contains a pump. This pump pressurizes ATF that flows through the valve body and causes actuators to move.

When you increase the engine speed, you increase the pump output...this can then overcome the leaking of fluid. Hence at low idle it is showing a problem, at high idle there is enough pressure.

A transmission shop (NOT BMW dealer; NOT BMW Indy) will connect pressure gauges to an AT and monitor shifting pressures, to help diagnoses.

You keep taking it to BMW shops and car places, I expect they will never find this issue (if it is trans)

That's what I have been trying to find out. What is the real issue? If I knew it is in fact the transmission, I may not even bother repairing it. Isn't an 8-speed transmission a sealed unit that you cannot work on? Except for the filter and solenoids.

That is what BMW will say but it is BS. If they put another transmission in they will send yours out to be rebuilt. They just don't rebuild them at the dealer. The just remove them and replace.