bmwbimmer

Hi,
I have a transmission slam that can be felt when coming to a stop from 2-1, and the gear shifts are rough sometimes, and I get a hesitation that I can slightly feel and see in the rpm when I take my foot of the gas, and when the car is stationary I switch to m1 to m2 or vice versa the car judder or jerk, I tried to drive in ds modes the car drives great and I dont get any 2-1 or jerky shifts just from 1-2 the car needs more rpm to shift, I was told that a software update would fix or mechatronics replacement but its very expensive, plz if any have this problem share with us how u solved it.

nagos420

pretty sure there was a software update for this

tonyb635

What about trying the transmission reset? I hear this works well, but it still might not fix your problem there. There are several post in here about how to do it.

Shlooky

1-Update software
2-Have the transmission fluids check and top off if required
3-Or if necessary change all fluids
4-Reset tranny

Should be good.

Only Bimmers

bmwbimmer,

Here is the real deal that is going on. I have been through everything with these trans and done quite a bit of investigation.

So it turns out that ZF and for that matter Ford (6R80 is an exact copy of the 6HP26 under license from ZF) as well stuffed a 6 speed trans into a 5 speed case. How do you do that? You make the clutch packs smaller. Well, what happens when you use smaller clutch packs? They wear way faster and have issues sooner. That is why they did away with it.

As it turns out the valve bodies or mechatronic units are failrly fast at switching gears. When it detects slip it switched to the next higher gear to prevent damage,etc. So this causes bumping. Sometimes its the 2-1 and sometimes it happens on other gears or clutch packs as well. The mechatronic units also fail at a high rate and require replacement. See www.thectsc.com as they have had the best prices that i know of.

To alleviate the bumping down low, ZF came up with a software update that BMW and Ford both use that maximizes the pressure in the transmission, holding the clutch packs firmer to stop slip. Every person who has had this 2-1 tip in done says the transmission feels as it is loaded all the time and acts differently. They are right. The 2-1 tip in will fix it, but at the cost of feel and possibly longevity.

Here is what i did in order
(1) Update normal programming
(2) Program for hard shifting (+HADS)
(3) Replace mechatronic unit (Some symptoms resolved, some still exist)
(4) New Fluid / Filer / Pan / Mechatronic Sleeve
(5) Remove +HADS from VO, Reprogram normal
(6) Program 2-1 Tip In (+21TI)

Car is now drivable but the feeling is different and some bumping exists, much better than before as It would bump / slam in all gears,

peachykonan

Please note - if bmwbimmer is driving a 530i, then the tip-in programming does not apply. As per CTSC (Klaus):
The 2-1 tip in does not apply to your vehicle, it is for 545, 645 and X5.

A mechatronic replacement will probably address the issue, but note that they suggest this only because it's guarantee-able. There's a more cost-effective fix but it's not an official BMW repair step: solenoid replacement thanks to Schpenxel's investigation. Specifically: solenoids + fluids + pan + mech adapter seal + mech sealing sleeve).

I drive a 525i and had the same 2-1 downshift slam + slam when changing between DS to D. I tried programming but it didn't work for me. I went the solenoid replacement route and after a month my transmission is still going strong (2-1 downshift gone).

bmwbimmer

tonyb635: I tried the transmission reset many times but it didnt work, you know what I remember the first time I made the reset my problem started back then I didnt have this problem.
Shlooky iltry an update hope it works
Only Bimmers thanks for the useful information!
peachykonan I talked to the indie he told me that my car doesnt have the replaceable soleniods im not sure if thats true.

AchtungE60

Now this is useful info. But where did you get these options from? +HADS and +21TI

AchtungE60

OP - I assume you have an M54 engine and same design. I've replaced the CAPS (camshaft position sensor) on intake side to take care of this issue on a few vehicles with same setup) 2000 528i, 2003 E46. All kinds of errors such as MAFS shadow errors and so forth. No CEL or any obvious errors. But in the end the CAPS was the issue. So I did it on another car I know was having same issue and guess what? fixed the issue too. Could be something other than transmission related.

marine8551

2007 550i, same problem verbatim, and add a slam when letting off a heavy accel. before an up-shift. A new mech. sleve fixed mine, 25K and still no issues. Good luck.