08 535i transmission malfunction

[buhlj1985]

So my car (08 535i sport automatic) has had issues since I bought it but I love it anyways. The issue I'm currently having is one that was one that presented itself right after I bought it. Floor it or give it more gas to pass someone or accelerate quickly and the transmission goes into fault mode after trying to up shift or when it downshifts after the acceleration and feel like it does shift but then glitches out. I had a bad voltage regulator relay that was frying my battery and alternators and that was what I thought the problem was. I fixed that. Few weeks later I'm getting on it to put a plastic mustang in it's place lol and the transmission faults. When it happens I pull over and and shut the car off restart it and the issue is gone. Not anymore. Now it will continue to do it any speed over thirty. Tried babysitting the pedal or flooring it. Doesn't matter. Will still go into fault mode the moment the transmission tries to down shift up or down. Tried in steptronic with paddle shifter and same issue. Right around third and fourth gear. Any thoughts on what I need to replace? I am on va disability can't afford stealership fees and am mechanically savvy anyways so if it's a part I can replace without a shop or hydraulic press or any computers I can handle it.

[dworthy]

Welcome to the Forum!

Just as a note, please do not use the term "stealership" here, as we have several Dealership Tech's that you are offending.

Second I would like to thank-you for your service from one brother to another.

Third, you will get nowhere on this car without a proper diagnostic tool. There are several on the market from a Foxwell hand-held unit to the BMW ISTA suite, and of course the prices will vary. What I would do if you have over 75k miles is start with replacing the trans filter and fluid. This would be purely preventative maintenance anyway, and you will still need to get the fault codes out of the trans and post them up so we can assist.

[pbonsalb]

Versions of the 6 speed auto in earlier year 5 series occasionally have transmission valve body solenoid problems. You can replace solenoids. There are kits and DIY if you search. This could be the issue in your 535. Changing the fluid and pan with integrated filter is not a bad idea. BMWs idea of lifetime might not be your idea of lifetime. You can buy kits for this also. And there is a mechatronic sleeve that can leak. The best 5 series tech info that I have found is on 5 series dot net though you can also find some that is applicable from the N54 guys on n54 tech dot com. A good scan tool definitely helps—the generics don’t do enough. Something like the $150 fox well nt510 gives you a free bmw specific module when you register it. There is also bmw Carly. And there are much better much more expensive factory levelTools we would all like to have but aren’t in the average DIYers budget, though smart computer geeks have put systems together for a few hundred dollars — check the diagnostic forum here for the best info on that.