2008 535i Transmission malfunction!
 

I'm on my way to work, pulling up to a stop, suddenly my car goes in park by itself, I try putting it in drive it would not go. I turn it off, turn it back on and it goes in drive without a problem. I took it to my mechanic to have it looked at, he said there's something wrong with the electronic shifter, not my transmission. The transmission seems to be working as it should. He quoted me close to 2k to have it fixed.
Does anyone ever have that problem? And I can I go about fixing it without spending 2k. Please.

The cable connector for the shifter might be corroded or have slime in it from spills. Try cleaning the connector with some electric spray and see what you get. Most of the time it will correct issues like this. It will only cost $7 and 30 mins of your time.

This^ your mechanic is doing the old "throw parts at it until it works" routine. It could be one cracked or shorted wire or connector, you just need to find it.

The cable you want to look at is the one that sits to the right of the shifter. It should be hooked on to it. you will need to take the iDrive knob straight off then the e-brake cover which is held on by a zip tie at the top and clips towards the bottom (squeeze toward the inside of the cover and it will come loose pull it back then cut the zip tie), you will need to take out the coin tray there you will see 4 screws you need to take out under it. The shifter lever needs to be pulled out (it will only be able to be pulled out when the car is in neutral, pop the menu buttons out and unplug, pull the shifter trim up and unplug (under that will be up to 3 screws you need to take out) lastly pull the wood grain up and out. I think i covered it all. Once you can see the shifter its sits on the passenger side of it. Unplug the connector and clean it good. Connect it back put the shifter lever back in to test it out. It should be working again as normal. Remember to unplug your negative cable while performing the clean and do not plug it back in until it is completely dry (canned air will assist you in that). While you have it apart you can fix your sliding coin tray if broken (just find the metal roll that came loose and put it back in its place (look at it for 2 mins and you will figure it out), clean your lighter if its not getting hot (soapy water or some type of aerosol cleaner) and the other plug that sits at the head of the shifter.

Great step by step by step instructions, thanks.
I'm gonna try it.

Which transmission fluid is the best substitute for ZF.
I'm about to change my transmission fluid and I don't have $220 for 6 quarts of ZF transmission fluid as recommended.
Can someone help, please.

This is a real can-o-worms question. There is the "only user ZF Fluid or else" camp and then there will be people who will point out that 6 quarts wont be enough to change the fluid - so if you use non ZF you will have a cocktail no matter how compatible it is with the transmission.

The non ZF fluid you choose may in fact specify a complete change (torque converter and all) so you will need lots more, and that could cost as much as 6qts of ZF.

My car is doing fine with Nulon (Australia) but I flushed with 12 litres ($160 AUD).

Are you also changing the pan, mechatronic sleeve and other related items?

Read KyleB's post https://5series.net/forums/diy-do-yo...thread-137584/

I guess my best bet is to go with ZF. I just was planning on changing the pan and fluid. You think I should also change the mechatronic sleeve also?

i'm using redline D6 with 4oz of lubeguard platinum universal protectant. I've got about 40k miles with it, everything's perfect buttery smooth, currently at 125k. I've decided to change fluids and pan filter every 50k, and will likely use the same stuff. This time, going to do bridge seal, sealing sleeves and mechatronic sleeve.

u can change your transmission with a working used one for just over $2000, I know because i had it done.

The shifter can be bought used for about $130