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-   -   TRANS.FAILSAFE-can be driven in this mode for how long? (https://xoutpost.com/bmw-sav-forums/x5-e53-forum/116537-trans-failsafe-can-driven-mode-how-long.html)

EODguy 02-23-2026 09:46 AM

Quote:

Originally Posted by andrewwynn (Post 1248591)
13.9v ?


–awr–

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I hope that's what he meant, because at 23.9v he's either about to ride the lightning or push a bricked X5.

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omodos 02-23-2026 09:49 AM

Quote:

Originally Posted by andrewwynn (Post 1248591)
13.9v ?


–awr–

Using Tapatalk VIP on iPhone

Hmm too high ?i will check again .....like i mentioned there is power steering fluid on halfvthe alternator not on the pulleys side....

andrewwynn 02-23-2026 10:14 AM

On the e53 should be 13.8 ± 0.2 if memory serves. And rock steady. Voltage swing is a prime candidate for trans failsafe. Been there.


–awr–

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Henn28 02-23-2026 10:42 AM

Quote:

Originally Posted by EODguy (Post 1248593)
I hope that's what he meant, because at 23.9v he's either about to ride the lightning or push a bricked X5.

Sent from Embassy network using Tapatalk


Maybe it’s the rarest of e53s, the mild hybrid!

EODguy 02-23-2026 10:48 AM

Quote:

Originally Posted by Henn28 (Post 1248600)
Maybe it’s the rarest of e53s, the mild hybrid!

[emoji1787]

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g300d 02-23-2026 11:02 AM

I've had a power steering fluid-covered alternator on the 3.0 with the GM trans for a long time and it never caused a transmission failsafe situation (now that I've said that I've probably jinxed it).

I experienced steadily worsening trans failsafe for a time on the 4.6 with the ZF. It was the transmission selector switch on the side of the transmission, losing contact inside, confirmed by pulling the switch, actuating it manually, and checking for continuity at the pins. Opening the switch, cleaning and bending the spring contacts for a better connection, and resealing the switch resolved it in my case.

Credit to Edwin (IIRC) of the E38 forums for his writeup on this which IIRC included the testing procedure, pinouts, and lots of pics.

omodos 02-23-2026 12:12 PM

Quote:

Originally Posted by g300d (Post 1248602)
I've had a power steering fluid-covered alternator on the 3.0 with the GM trans for a long time and it never caused a transmission failsafe situation (now that I've said that I've probably jinxed it).

I experienced steadily worsening trans failsafe for a time on the 4.6 with the ZF. It was the transmission selector switch on the side of the transmission, losing contact inside, confirmed by pulling the switch, actuating it manually, and checking for continuity at the pins. Opening the switch, cleaning and bending the spring contacts for a better connection, and resealing the switch resolved it in my case.

Credit to Edwin (IIRC) of the E38 forums for his writeup on this which IIRC included the testing procedure, pinouts, and lots of pics.

ok thanks for heads up on this re power steering fluid on alternator...volts are 13.9v car started and as read via no.9 in obc...
Just hoping gonna find a mechanic at short notice that doesnt have 2 week waiting list...plus other than the visual inspection for leaks the fluid level can be topped up at least....will scanning tools point to the transmission selector switch if it has a fault?

haigha 02-23-2026 02:21 PM

Quote:

Originally Posted by wpoll (Post 1248583)
Pretty sure you have the six speed ZF 6HP26Z transmission, so it won't likely be water in the trans. connector. In addition, our 3.0D models have a large plastic splash guard covering the transmission, well, splashes. :-)

What might be an issue is the rather common trans. fluid leak from the mechatronic seal, resulting on low fluid levels. This can be hard to spot, since the leaking fluid is often trapped in the splash guard - no tell-tale fluid spots under the car.

Agreed, a very likely cause! In my case there was a puddle of ATF on my garage floor under the transmission, but I have the 4.4i.

omodos 02-23-2026 03:21 PM

Quote:

Originally Posted by haigha (Post 1248606)
Agreed, a very likely cause! In my case there was a puddle of ATF on my garage floor under the transmission, but I have the 4.4i.

Ta for all replies...will plead with mechanic to check level and if low at least top up , not sure how tricky or time consuming on a 3.0d this will be. And hopefully will give me more time till the possible leak is resolved unless of course the leak is big one not gradual...okays appreciate again all feedback...

wpoll 02-23-2026 05:02 PM

If, as you now say, it's coming up in trans. failsafe when you first start the car, it's less likely to be low fluid. It's more likely it's a hard fault... :(

A fluid level check and a scan will reveal much...


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