Trans failsafe + no gear indicator on dash
 

Hello everyone

New issue on the X

So to resume the car would get into trans failsafe and also no gear indicator on dash, it drive but in limp mode. Sometimes getting the key off for 30seconds and key on again fixes it.

It works or doesn't work after turning the key then stay working or not working until next key off/on. It doesn't happen while driving when the issue isn't present.

But since today it refuse to work again no matter what, I didn't try clearing the codes again.

Codes are:
P0753 shift solenoid 'A' electrical
On dis: solenoid valve 1

So is it simply the solenoid or it could be something else or low oil in the transmission?

Looks to be a bad solenoid based on the error. I had this same issue on my e38 until one day, no idea how but it came back to life on its own. I did end up replacing the trans with a lower mileage rebuilt one since the original one had high mileage. Do you have a 4.4 with a 5hp24?

Yes it's the 5hp24. Car has 300k km

I don't trust generic P-codes to always be accurate, but....

As someone who has had this issue before I will give you all the places to look.

1. Interlock cable @mechatronic gearshift.

2. Magnetic reed switch on the valve body mechatronics. (if lucky cleaning will fix)

3. Solenoid and valve body seals.

4. Shit luck and it's a crack in the valve body channels allowing pressure bleed over.

A scanner like the Foxwell nt-510 or nt-520 (200 USD) will show you more data and what your gearshift is in vs what the transmission is in. A difference between the two will give you the symptoms you described, some of the fixes are easy, some cheap and some completely peg your fun meter...

Here's some pics of the different repairs I had to do, but missing the gearshift and reed switch pics.

Also be very very gentle with the gearshift cover as the tabs break easily and over tightening the shifter will put some gears out of position enough to not engage. https://uploads.tapatalk-cdn.com/202...3fd0bcf7cc.jpghttps://uploads.tapatalk-cdn.com/202...99745dca1b.jpghttps://uploads.tapatalk-cdn.com/202...474317b085.jpg

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Thanks for the infos

Today my girlfriend used the car and told me when in reverse it accelerated by itself and she almost hit a wall.

What do you think it could be with that added info ?

Honest guess....

Transmission wasn't engaging and she gave it more throttle and then it engaged under high RPM.

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Valve body then ? Or clutch or torque converter?

Truly hard to say but do you have your fill times and clutch pressures? Any codes (not p-codes) BMW ones?

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I'll check on inpa.
Error in dis is solenoid valve 1

Read my thread I shared from my E38 with the 5hp24. A failed solenoid will cause no gear indicator and trans failsafe. I believe I shared how to test the OHMs and shared the expected values. You may be able to do as little as drop the pan and replace the bad solenoid if it is deemed bad to get it back. This info was obtained from a range rover thread someone shared on Xoutpost.

Ok, also what is your voltage?
Bad battery or alternator could be allowing solenoid issues to occur...

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Very true!! [emoji106]

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It's stabilized at 13.9 using USB charger with voltage indicator but when changing gear or activating xenons or anything electric it goes down then up again, sometimes there is spikes at 14.5 but very rare. It always did that but it never affected the gearbox. I changed alternator 8month ago

What is the interlock cable? I'm not native English. Is it the cable from the gear shift knob to the gearbox ?

Does the symptoms I described can be caused by that ?

The Interlock Cable functions to prevent accidents caused by shifting of gears in a state where the brakes are not actuated by the driver's careless operation in an auto transmission vehicle. So it can cause an error in the readings of the computer thinking that it's in the wrong position making transmission positions lock out or disengage.

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I saw that definition but where is that cable?

You can see the rod at the end of the cable in this picture from CapeX5https://uploads.tapatalk-cdn.com/202...b9d3bc8f53.jpg

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Where it goes to ? Under steering wheel ?

Today I drove the car and it lost gear position while driving.
Checked gearbox temp and it got to 135degrees Celsius.

I did the test with inpa and all solenoids where failed plus the interlock. Only reverse light reported ok.

When in park if I didn't press the brake I couldn't go to drive so interlock is fine ?

Yes your interlock cable sounds fine.

Did you happen to check that gear positions as reported by transmission match what is reported on display and gearshift positions?

With your solenoids showing as toast just buy a valve body, solenoid repair kit and have the old valve body checked for cracks. Don't forget a complete filter, seal kit to complete everything.

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When it shows on dash it's reported correctly, it also shift fine.
The issue is just when hot the car loose gear indicator on dash and it goes in trans failsafe.

Can a damaged valve body cause overheating? And failing solenoids no dash info about the gear position ?

And sometimes even when hot and no dash indicator just removing key and puting it back it works again (gear indicator comes back)

Yes a crack in the valve body can cause your problems and a malfunctioning transmission is working harder while still getting an ton of power shoved into it.

Rebuild kits aren't too expensive, just make sure of your exact model by checking the tag on the transmission. https://uploads.tapatalk-cdn.com/202...48611e1f1f.jpg

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A cracked valve body or failed solenoid can cause no gear indicator on dash ?
I saw these kits but I don't have the knowledge to do it myself :/

Leaks in the valve body no matter how they occur keep sending mixed or no signals to the computer and that is why it doesn't show, shift, etc.

When you were a kid did you play with any toys putting square pegs in square holes, round pegs in round holes?

Every put together any item from Ikea?

If you have then you can do the valve body. We are not taking about doing the drums/clutch packs or anything like that, only removing the oil pan and the valve body mechatronics sandwiched between the pan and the main body of the transmission.

If you're still nervous about it then I suggest you take it to an independent transmission place and see if they will rebuild it with your parts vs theirs and having a good idea of what's wrong should keep them from slipping you the high hard one...

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Ok thanks for the explanation.
If I go that route do I have to buy anything else ? Joints, o ring?

Sadly the solenoids for this 5hp24 model is only available in china for 120, or from zf at 1400euros :/
Valve body also only available in china (400euros).

Is it better to replace only the solenoids or since my gearbox is overheating it certainly cracked?

I don't think buying an used one even with less mileage is a good idea ?

Also can it be the solenoids if when trans failsafe + no dash indicator I can still do drive, reverse, park, neutral without any issue ?

https://www.pieces-bmw.fr/

https://www.online-pieces.fr/bmw-pie...hp?language=fr

https://www.daparto.fr/pieces-auto/B...hoCDygQAvD_BwE

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Thanks for the links.

So I'm driving the car myself now and actually with engine cold I never have the prnd on dash and it goes into trans failsafe. When engine reach 60degrees approximately or sometimes only when it reach operating temperature I just have to cut engine and start again and it works normally. I can go full throttle each gear in manual or automatic mode with 0 issue.

Error codes are EGS line signal disturbed and solenoid 1.

Have you already checked the easy stuff like gearbox control module (EGS) and it's wiring in E-box beside DME?

I bought an used egs and same thing I didn't see broken wires when replacing it

The egs line signal distrusted error may have been from the egs swap but the solenoid 1 error is most likely electrical? I'd say solenoid 1 is your issue and you should at the very least replace that one but would be worth replacing all of them when the valve body is out. My original e38 trans randomly started working when I had experienced this similar issue weeks or months later but I ended up replacing the trans with a low mile rebuilt one since the original trans was having other issues like torque converter growling/groaning as well.

Ok I'll replace the solenoids. But should I replace the whole solenoid block or it's not necessary?
I should buy something else if I replace the solenoids only joints o-rings ?

I mean that's the best "while it's out" option

I won't risk doing it myself I think the mechanic won't remove it and just replace the solenoids. Solenoids are at 120euros and the block 400euros but I guess changing the whole valve body isn't necessary? What could be the symptoms if there was a crack or something else?

That looks like a 6r60 Ford valve body. Had it been replaced before?

ZF transmissions are used in the super duty trucks I believe so it wouldn't surprise me that they'd look almost identical.

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The Ford 6R80 is the ZF 6HP26 made under license..... not sure how interchangable the parts are though.

The 6r60 valve body is similar enough to be swapped into the 6hp26 provided you use the TCM from the 6hp26.
The 6r80 valve body is too different , it cannot be used in the 6hp26.

[emoji108] at least I now know of additional guts if needed (knocking furiously on wood) [emoji1787]

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yeah... that! :rofl:

Hello.
So a mechanic changed the solenoids + electric cables and now it's worse.

https://youtube.com/shorts/R6OCYTrQ_...8_JByBTN5h65Xp

Did that when cold then after doing reverse then drive multiple times went away

Scanner say oil temperature sensor error + internal error on egs