[zachattach12]

Hey y’all, hope I get some help from those of you more knowledgeable.

Vehicle details:
2011 BMW 335d
123k miles
ZF 6HP28 transmission (I think this year had the 28 instead of 26)

Symptoms:
-Engine runs fine, no codes
-At idle, no limp mode or other transmission related codes occur.
-When shifting into gear there is no movement and no limp mode.
-When revving to about 1.5k rpm while in gear the transmission limp mode shows up in CIC. (Code 4F84 on TCM)
-When shifting into Reverse from Park, the CIC displays that transmission is in neutral (verified by looking at like data on ProTool as well).

I finished swapping a new block in my car (old engine spun main bearing #1). Replacement engine is running fantastic however the transmission isn’t working at all. Prior to the swap, the transmission was working no problem. I serviced the filter, fluids, seals, and sleeves about 12k miles ago (currently at 123k miles).

Double check that I have everything connected: I have the 4 bolts from the flex plate to the torque converter installed, I installed the 3 bolts from the output of transmission to driveshaft, I have the electrical connector above the pan connected (TCM shows up using ProTool), I have the physical cable to the gear selector connected, I left the transmission cooler attached when I pulled the engine and trans so I didn’t loose any fluid.

I DID leave the transmission just sitting on its transmission pan while I got the new engine ready. Is it possible that I cracked that rectangular sleeve above the valve body by doing so?

Protool is spitting out the following error 4F84 “Ratio Monitor, Clutch D”

What I am going to do next:
-I ordered another complete mechatronics kit from FCP Euro (Pan/Filter, fluid, sleeves, seals, etc...) and service it while it's still on jack stands.
-The transmission thinking it's in Neutral when I shift to reverse hints that maybe I need to adjust the physical cable that shifts the transmission?
-Could this be an electrical thing? Am I missing a ground cable somewhere on the wiring harness?
-I pulled the engine and transmission together, when doing so it came out at a pretty steep angle, did I drain all the fluid out of the torque converter or something? I imagine the pump in the transmission would fill it up rather quickly.

I appreciate any other leads you can provide.

[Tomnavigator]

In my 50+ years of working on vehicles, what I have found is that new problems are usually caused by something you did while working on your vehicle. If the only thing you did to the transmission was to disconnect the cable and electrical plug, I would bet on the transmission cable or the electrical plug. Adjustment and or binding of the cable. Especially with the DIC indicating neutral when in reverse. Also disconnect and reconnect the electrical plug to the transmission. I would disconnect and reconnect several times to be sure there is no corrosion on the contacts. It may not be making electrical contact in some of the terminals of the plug. Ensure it is seated all the way together.

[Tomnavigator]

I would not do any work internally on your transmission at this time. There is no reason why disconnecting the transmission would cause internal issues. Don't add any new unknowns by doing internal work on the transmission since it was working with no issues before you disconnected it. If I had to bet, I would bet on the cable.
Also, look for another electrical plug that could be hidden and overlooked when you plugged everything back up. I would not be surprised if there is some sensor that has an electrical connection.
Recently, I replace the heads up display on my 2003 corvette. The dash had to be totally removed to do this. After I put everything back together, the turn signals did not work. It turned out to be caused by my failure to connect the emergency flasher switch located on the front of the dash. The wire had fallen down inside the dash where it could not be seen and I did not notice this when connecting up all the other plugs. Who would think that an unplugged emergency flasher switch would kill the turn signals. The point of this story goes back to what I said earlier. New problems are usually caused by something you did. Cable adjustment and/or something not plugged in correctly are probably the cause of your transmission issues. Imagine the time and effort I could have lost tracing out the turn signal wiring and bulbs to find out why the turn signals were not working when the cause was an electrical connection in the dash that was not plugged in.
Can you disconnect the transmission cable and shift the transmission linkage manually to see if the transmission is working correctly? you should be able to see the tires turning correctly in reverse and drive. Note: Since this transmission is electrically controlled, this may not work unless you move your shifter to match the gear you are selecting manually because the signal for the gear selection to the transmission control module may come from the gear selector not directly from the transmission. This will be much easier if you have a helper to shift the gear selector as you shift the linkage.
1) Disconnect the transmission cable
2) Start the engine and shift to reverse with gear selector on console.
3) Go under car and manually shift the transmission to see if transmission shifts and tires rotate in reverse.

[zachattach12]

Hi all, just wanted to close the loop on this thread, I discovered what it was! Unfortunately it doesn't end well for the transmission. So when I was mating the transmission to the new engine, I did not align the torque converter to the transmission's oil pump (doh!). Somehow I was still able to get the flex plate bolted up to the torque converter but the toque converter notches didn't align with the prongs on the oil pump. Well when the engine first started up it sheared off those prongs and as a result there was no hydraulic pressure for the transmission to operate. Well instead of rebuilding the transmission and chasing down debris and potential future problems, I found a donor transmission with 57k miles only 30 miles south of me. It was out of a '10 335d so it is a ZF 6hp26 instead of a ZF 6hp28 but everything is working currently and I didn't even code the vin on the TCM.

Hope nobody else makes this mistake, ShopLifeTV has a great video that explains the exact f*ck up I made:

Evidence of the carnage:

View post on imgur.com

[zachattach12]

And now that I have your attention, the replacement transmission is starting to make a funky noise and I CANNOT locate where it's coming from.

So it shifts just fine and I replaced all the sleeves and seals above the mechatronics unit before installing but now there is this thumping/tapping noise that I can really only hear it inside the car. It sounds like it is probably coming somewhere from inside the bell housing? It goes away when in reverse but is audible in park, neutral, and drive. It does seem to be correlated to RPM. It's not engine related because I got up to speed, threw it in neutral, and turned off the engine and it was still audible when coasting.

Here is the sound clip:

[lnxguy]

There is only one transmission offered in the M57 e70 and e90s, it's the 6hp28. Year doesn't matter, they're all the same.

Where people get confused is it's referred to as the 6hp26z as well 6hp26z = 6hp28.