1St jumping back into neutral HELP!!!
 

This just started and I have no idea why but when I slow down enough to drop back into 1st, intermittently upon acceleration, it revs up, of course, and then bang, pops into 1st and jolts. What is happening exactly and where do I start to look first?

Thanks

Sounds like transmission is screwed. Go get a shop to check it out.

Something not working right (sticking) in the valve body (mechatronic)?
I would try to change the oil, 3 times in a row to make sure to dilute enough to have new oil in there. Drive one week between the changes.

Mine was starting to do that intermittently (once or twice a month) and I did 3 oil changes with a week of driving in between, and now it is fixed.

search this forum for transmission slam and see if that is what is happening to you?

Thanks Guys!! I'll definitely work at flushing my tanny this weekend.

I have been talking to a couple mechanics already this morning who have worked on other vehicles and they say that dropping the transmission pan and replacing the filter and gasket while doing a tranny flush is important and while the transmission pan is down, rinsing the area with brake clean to rinse as much garbage out as possible is definitely hugely advantageous in cleaning out the transmission before installing the new filter and gasket and then putting good quality synthetic oil in it. Is this doable with the X5 transmission?

It is doable, and exactly what you should do. But one thing, I would not flush the trans. Only replace whatever fluid came out. Do not swap out all of the fluid in one shot. Shit can get "shocked", and you might have a complete trans failure. Also note filling procedure. Search here, search my name if you want. I did a write up on dropping the pan. 4.8is, but still.

Awesome!! I found your post including pics. This is definitely going to help me save a ton on not only doing it myself but also knowing that it was done right. I really appreciate it. Thanks.

So my buddy and I emptied the oil that looked more like used engine oil after about 10,000kms and refilled it with standard ATF 3. We took it for a drive to mix it up and then drained it again, then filled it back up again. Now that I have the filter and gasket, I'll buy some more ATF fluid for the final flush. I'm feeling a lot better about getting so much of the used oil out although I know it doesn't take much black die to turn any other colour dark. Once we drop the pan and replace the filter & gasket, I'll feel a lot better. I hope this solves my problems with shifting. I can't believe BMW does a flush and recommends keeping the old oil in the vehicle. That just makes zero sense to me. If I would have purchased the oil from BMW, it would have cost me $50/L. That is insane if you ask me.

Please make sure to use oil that is to spec. Some will say use the exact fluid that is in there, and I agree, but at least make sure you get the fluid that meets specification for your trans.

Yesterday was the big day!! My transmission had been really acting up and I couldn't wait for the work day to be over so my buddy and I could tackle this project. I got to his place and we quickly pulled the plug to drain the oil while letting everything cool down.
Working together, we loosened the 20+ screws holding the oil pan on. We left one at the oil plug side and two at the opposite side of the pan on the end so we could slowly lower the oil pan while still draining it until there wasn't much left to drain. After pulling the pan off, we were glad to see there wasn't any hard particles stuck to the magnets as we worked at washing them off. The filter was completely plugged and definitely due to be changed out. I couldn't get over how expensive new transmission oil is for BMWs but everyone I talked to told me to buy the stuff specific for the brand of vehicle so I did reluctantly.
We used gasket spray to hold the gasket in place, which worked awesome!! And before long we had the new filter back in place along with the oil pan and all the bolts in and we were filling up the oil pan. My buddy has a drill pump which worked AWESOME attached to his cordless drill. I strongly recommend buying one. We sucked up 3L super quick, ran the vehicle for a bit and then added the fourth and that was pretty much it.
I took it for a drive and even though it jumped out of gear a twice out of the 15 or so times I started off in 1st, it made a huge difference!! Today on the way to work, it only jumped back into nuetral once so I'm pretty happy over all. I still have 3L of new oil left so I'll probably drain some oil out in a couple thousand KMs and top it back up with new stuff again just to keep cleaning out the oil a bit more.

If anyone else has any other suggestions, I'd be open to hearing them. I was looking at the Dinan transmission upgade software thinking maybe with it getting reprogrammed, it might help it decide which gear it's suppose to be in but feedback would be helpful. Thanks for all of the advice from the guys on the forum. I feel a TON better then before.

Cheers

I would suggest to do 2 more oil changes. One oil change like you did only replaces half of the oil. After 3 oil changes, I think you get like 92% new fluid in there.
Also, no need to drive thousands of km before another change. One week or 500km is enough to mix everything and condition the internals with the new fluid.

Update. Yesterday was a warm day and I was doing quite of bit of driving through the city. While the transmission was still cold, everything worked well!!! I was very happy. Once it warmed up, I was right back to square one with it eventually kicking into trans safe mode which really sucked!!!
I'm thinking it's got to be electrical but I'm open to suggestions. Even when it popped back into neutral or between gears, it did it smoother then before which was relieving but I've GOT to figure this out soon because it sucks trying to get through an intersection when it keeps jumping out of gear or you're taking off in 5th while in safe mode.

I had done three oil changes which really showed when I pulled the pan and saw how clean it really was.