Replacement Transmission stuck in neutral

[jfandl]

I've got a 2014 x5 that I had to replace the transmission because a broken driveshaft put a hole in the side of it. I installed the replacement xxx864 transmission which is an 8hp75, instead of the original 8hp70. I switched out the mechantronic from the original trans (to bypass the ISN lock), however the 8hp75 has the newer neutral bypass lever without the screw. After fully coding the vehicle, I continue to get the code:

421342 - Position specification: undesired power transmission in neutral detected

The donor car has 48K on it and said it worked but I'm not having any luck after coding it.
I found the tool to force it into neutral, but my issue is that it looks like it's being forced into neutral without moving the lever. See the video:

The car will go into D no problem, but once you hit R, it faults and locks to neutral.
Any suggestions on how to troubleshoot it further? Could the lever be stuck that maybe moving it a few times will free it up?
ISTA is saying to check the adjustment screw but that doesn't exist on this tranny.

[Chilled]

Is the Neutral paw in the correct position internally? What ever it toggles.

Also are you sure the valve blocks are compatible?
Found this training manual, and on page 98 it has the solenoid order.
https://akpphelp.ru/images/contents/...tvo_manual.pdf

This order looks identical to the other vids I've seen of 8HP70 teardowns, however the 8HP75s valve blocks order looks different. Based on colour at least.

8HP75

8HP75

8HP70

8HP70

[jfandl]

Valve blocks had to remain on the respective transmission because yes, they are different (per the transmission mechanic) as the holes for some valves do not line up . He swapped out only the mechatronics.
I'm going to try to move the park release lever tonight to see if it makes any difference now that I learned how.

[Chilled]

Ah fair enough.

What about the solenoid order on the mechatronics? Is it the same? As in if you look at the last 3 solenoids (A, D, B). Based on the manual and the vids. The order seems different between the 70 and the 75.

If you look at the solenoid usage vs the mechatronics order. The difference appears to be that solenoids D and B are swapped. So looking at the usage chart, solenoid D is disengaged for Reverse but is used for Park, N and Drive whilst solenoid B is constantly used.

So if the mechatronics has the pinout swapped for these between the 70 and the 75. It could explain why it works in P and D, but when you hit R, it actually actuates itself into N and faults.

[Chilled]

Does anyone have a workshop manual for the 8HP75? tried looking around and it seems the info on the 8HP is scarce (to the public) and the only manuals I could find all where behind pay walls.

Not sure on the content or the level of details they have.

[RED_Y_]

ISTA doesn't have a manual for the transmission, the only information provided is replacing the tranny, that's all.

[jfandl]

Originally Posted by osmansiddiqui95

Also what X5 is it? My 2015 f15 x5 n55 had the 8hp45 in it.

It's a 2014 X5, F15 with the N63TU. It originally had the 8hp70 trans in it.

[jfandl]

Taking it to the transmission shop next week that installed the used transmission for them to check it out.

I did take it out to test drive it. It shifts a little hard into D, but I can drive it in 1st, 2nd and 3rd. When it shifts into 4th, it revs up, similar to being in neutral but with a little resistance (like a slipping clutch), then it drops back into 3rd gear. Drivetrain malfunction comes on at this time. Sport mode and manual mode as disabled after this happens.

I've attached the fault codes from ISTA.

Could be a long shot but since the mechanic swapped out the mechatronic from my old 8hp70, could it be causing these codes because the 8hp75 has slightly different gear ratios? I programmed the transmission with the CAFD for the 8hp70, not sure if there is a different one for the 8hp75?

[Chilled]

Originally Posted by jfandl

Taking it to the transmission shop next week that installed the used transmission for them to check it out.

I did take it out to test drive it. It shifts a little hard into D, but I can drive it in 1st, 2nd and 3rd. When it shifts into 4th, it revs up, similar to being in neutral but with a little resistance (like a slipping clutch), then it drops back into 3rd gear. Drivetrain malfunction comes on at this time. Sport mode and manual mode as disabled after this happens.

I've attached the fault codes from ISTA.

Could be a long shot but since the mechanic swapped out the mechatronic from my old 8hp70, could it be causing these codes because the 8hp75 has slightly different gear ratios? I programmed the transmission with the CAFD for the 8hp70, not sure if there is a different one for the 8hp75?

Interesting. When you say Mechatronics, are you referring to the black plastic bits that control the solenoids. So you strapped the 70 mechatronics to the 75 valve block? Because looking at the chart, and the vids above. It does kinda explain why you can't get into R and 4th.

Does ISTA have a way to see the mA applied to each solenoid?

[jfandl]

Originally Posted by Chilled

Interesting. When you say Mechatronics, are you referring to the black plastic bits that control the solenoids. So you strapped the 70 mechatronics to the 75 valve block? Because looking at the chart, and the vids above. It does kinda explain why you can't get into R and 4th.

Does ISTA have a way to see the mA applied to each solenoid?

Yes, the Mechatronics is the black plastic electronics that connects to the valve body and has the EGS connector on the trans.

I see what you're saying since the different color solenoids indicate if the are NO or NC. The mechanic told me he tried to swap the valve body but could not since the holes do not line up so he only swapped the mechatronic. I have the mechatronic from the hp75 AND the valve body from my Hp70. Here is a pic. You can see the solenoid pattern matches your table #2 for the hp70. I see clearly that the solenoids in the video for the hp75 are in a different NO/NC order so if the mechatronic is trying to activate them differently , it would definitely be an issue (unless that's a different manufacturer? - I don't know).

In the end I have the HP75 installed with the HP75 valve body and a HP70 mechatronic. The Boot loader, SWFL, CAFD are identical between the installs on the hardware. I know this because I flashed it before the mechatronics were switches and the trans would not go into gear (thanks to the ISN lock). I did notice that the HWEL is different between the two:
1B8D-001-010-002 (hp75) vs 022A-004-012-003 (HP70) -I tried to remove the hardware via ESYS and tell it's the 1B8D hardware but I have not found a way to avoid a hardware mismatch when flashing, even after editing TAL file to tell it what hardware to expect.

In the end, if you're right, I will need to install the mechatronic from the hp75 and ISN unlock it. Then it will be hardware matched.

Right now, it's a bit of process of elimination to figure this out but I think you may be right. Any thoughts from anyone?

[Chilled]

Sorry the software and coding side completely looses me. It's something that I have not spent any time on and am petrified to play and brick my car. I wish I had your confidence.

Looking at the ISN reset and clearing old settings from the mechatronics and with the post above. Saying that this can be done remote. I did find that it appears to be done remote via eSYS. I also did see allot of post saying that it needs specialized tools but.. who knows.


Does this vid mean anything to you?

Also, see the posters comment on flashing in the car
>>>
Second flash with factory files finalizes the process. This video was recorded using an on the bench setup of the egs unit. When working with an actual vehicle, second flash would cause egs to be in sync with cas & dme and hence to appear locked again.
<<<

[jfandl]

Originally Posted by Chilled

Sorry the software and coding side completely looses me. It's something that I have not spent any time on and am petrified to play and brick my car. I wish I had your confidence.

Looking at the ISN reset and clearing old settings from the mechatronics and with the post above. Saying that this can be done remote. I did find that it appears to be done remote via eSYS. I also did see allot of post saying that it needs specialized tools but.. who knows.


Does this vid mean anything to you?

Also, see the posters comment on flashing in the car
>>>
Second flash with factory files finalizes the process. This video was recorded using an on the bench setup of the egs unit. When working with an actual vehicle, second flash would cause egs to be in sync with cas & dme and hence to appear locked again.
<<<

Yeah, the esysX looks like a great tool for resetting the ISN. Unfortunately I reached out 10 days ago and have yet to get a response. I was hoping to try this before I had the mechatronic removed but like others are saying, I tend to believe it's probably a physical issue with the transmission.

[Chilled]

Didn't know there were different versions. Let me know if you find the fix. Would sux to have to get another transmission for a solenoid miss match and potentially be back here again with EGS lock.


Btw, have you tried to reach out to someone who maybe has it. If the site owner is not selling it, maybe they would be willing to help out.

[Tomcat_F15_STL]

I'm not trying to be mean, but playing mix-n-match with BMW components is a bad proposition.

[Chilled]

Yeah but a fun one.

Personally I would love to see some try to shove a 95 under a F85/86. Both are gen 2 and the valve blocks look identical. Before anyone tires, those things are longer than a 75 so new drive shafts and I have no idea on bolt pattern/compatibility for the Transfer Case.


Any update if you got a dud box, or managed to find someone with a correct scan tool to clear the EGS?


*Edit, well that dumd idea is done for. It looks like the starter will not clear the housing.

[jfandl]

Originally Posted by Chilled

Didn't know there were different versions. Let me know if you find the fix. Would sux to have to get another transmission for a solenoid miss match and potentially be back here again with EGS lock.


Btw, have you tried to reach out to someone who maybe has it. If the site owner is not selling it, maybe they would be willing to help out.

Solved: The transmission is now working in the car. I want to give a shoutout to Chilled who was the one who helped me to identify the actual problem.

It's been 10 days and the transmission shop still does not have me on the schedule until this Wed at the earliest so I really got tired of waiting and decided to swap back the mechatronic in my driveway myself. It really wasn't that difficult but a helper was necessary. Swapping the physical mechatronic on the valve body took less than 20 minutes on the bench so that was easy.

Here's the summary

• The Mechatronic from an 8HP70 is physically different from an 8HP75 and will not work in a different series transmission - They changed the valve bodies and the solenoids are in different positions so there's no way for them to work
• I had a coder from the Netherlands (Thanks Simon) unlock my mechatronic remotely (esysX) - funny enough, I had the mechatronic hanging off the side of my car and connected to the round connector when he unlocked it and coded it. (a good idea for someone to prestage the coding of a replacement mechatronic before the trans shop ever sees the vehicle - this way when they fire up the car, it's ready to go) Yeah, it looked red necked but it worked for programming it before swapping the mechatronic back in the car.
• As soon as he unlocked the ISN, the gearshift lit up and D started flashing.
• After starting the car, it was locked in Park so I had to clear the previous transmission codes - the car went into all gears as soon as this was complete.

Test drove after this - the Beast is finally back on the road.

I want to thank everyone who provided feedback here, it's great to see a community come together to help out.

[Chilled]

That's awesome, its good to hear you got it sorted.

I wish there was a way we could get a copy of esysX, even if it is just to save and store somewhere as another tools in the toolbox.



BTW, you mentioned you did some coding for the 75. Was that to the 75 mechatronic/or car itself or did it end up just been bolt up trans, reset EGS and all good?

[blue dragon]

I thought the guy who wrote esysx passed away, thats why there are no updates.

[Chilled]

Oh, no. Thats suxs.

His probably gone to better place. Where the E65 did not exist.


We should definitely archive the software somewhere now.

[jfandl]

Originally Posted by Chilled

That's awesome, its good to hear you got it sorted.

I wish there was a way we could get a copy of esysX, even if it is just to save and store somewhere as another tools in the toolbox. (Would be nice)



BTW, you mentioned you did some coding for the 75. Was that to the 75 mechatronic/or car itself or did it end up just been bolt up trans, reset EGS and all good?

The Mechatronic had to be ISN unlocked before it could be coded. Once it was unlocked, it was updated with a recent I-Step flash. I tried to flash it before it was ISN unlocked and it would give me an Ethernet error preventing me from updating it.