2006 transfer case transfailsafe

fatjohnny · Post by **fatjohnny** » Sun Feb 09, 2025 11:27 pm

Hi, main dealer has diagnosed a problem with the transfer case, but when talking to a transfer case repair centre, they say that transfailsafe has nothing to do with the transfer case.
Can anyone confirm that or has anyone has a transfer case issue throw up transfailsafe?

Alan Gunn · Post by **Alan Gunn** » Mon Feb 10, 2025 5:46 am

A fault code scan if needed first off.
Preferably with bmw kit.
Main dealer is the last option as you paid them more than your own scanner would have cost and still none the wiser.

Greydog · Post by **Greydog** » Mon Feb 10, 2025 8:19 am

I would ask how they reached that diagnosis, Trans fail safe can be triggered by Low Battery Voltage, Low Trans Fluid levels (when was it last serviced?) Torque converter even a poor connection at the gearbox loom plug can cause issues the list is lengthy
As Alan suggests you can buy a good BMW capable diagnostic scanner for less than the cost a Main Dealer may charge for a single diagnostic session

fatjohnny · Post by **fatjohnny** » Mon Feb 10, 2025 8:32 am

Thanks for the replies. I'm convinced it's not the TC but an electrical failure. Some more information: dealer originally diagnosed a leak on the gearbox electronic connector, changed it, Inc new oil, filter etc. 2 days later problem returns. In August I put a new alternator on (Bosch). Battery is relatively new. I pulled fuse 46 to deactivate the TC. Drove fine, albeit with warning lights, then transfailsafe appeared. I have a copy of ISTA. In some way I think the fault is a sensor or damaged wire. It's just where to start. ISTA isn't showing any ABS faults. I'm just looking for ideas to start and order of elimination please.

Alan Gunn · Post by **Alan Gunn** » Mon Feb 10, 2025 8:49 am

I got the trans fail safe warning once it turned out to be the suspension level sensor.
That was on my 2002 e53 3.0d automatic.

Greydog · Post by **Greydog** » Mon Feb 10, 2025 9:06 am

I would start with the battery even though you say it is relatively new I have known a 6 month old battery fail (make sure you have a reciept ready). Trans Fluid level make sure it is correct and top up if required (make sure you use the correct fluid) Check the Transmission Plug is seated correctly. those are the simple things

fatjohnny · Post by **fatjohnny** » Mon Feb 10, 2025 3:14 pm

Hi Greydog,
Thanks for your advice. Can I ask a rather naive question. I've just gone to check on the gearbox electronic connector. Should it be a really tight fit as this one seems to move a little, which seems very unusual for an electrical connection. I've not unscrewed it yet, it's not exactly accessible.

Greydog · Post by **Greydog** » Mon Feb 10, 2025 5:19 pm

My guess would be yours isn't seated correctly it should be a tight fit. From memory they can be a PITA when I did trans fluid on the E53 getting at the locking ring was a real sod. First check that there are no leaks around the sleeve the locking ring seats onto then push the plug right home and twist the locking ring into place
Fingers crossed it's your fix

fatjohnny · Post by **fatjohnny** » Mon Feb 10, 2025 5:55 pm

It was a bugger getting off. Tight to get your hand in. Got it off, sprayed it with contact cleaner. Once dry I've reassembled it. Fingers crossed.

henrym3 · Post by **henrym3** » Mon Feb 10, 2025 9:27 pm

Don’t automatically rule out ABS faults because there are no fault codes. Check the wheel speed sensors on diagnostics ie drive the vehicle while the diagnostics are plugged in and make sure they all read the same speed. Don’t discount the ABS module which was a notorious weak spot on the e53 and never showed faults even when it had. Main point is was it driving and changing gear ok and then you got transfailsafe. If it was then the chances are it’s an electrical fault. If I’d have taken garage advice I’d be on my 5th gearbox by now. Hang in there and Good luck.
Make sure you know the correct way to check the oil level ie with engine running and g/b oil at right temperature. I’m sure though that BMW would do the fill up in the correct manner.

fatjohnny · Post by **fatjohnny** » Mon Feb 10, 2025 11:18 pm

Hi Henrym3,
I'll be honest, I've never connected a scanner and driven the car. I've got ista D on my laptop or a Creader elite(bmw). Could you just tell me what I should click on please.

fatjohnny · Post by **fatjohnny** » Mon Feb 10, 2025 11:35 pm

Hi,
Yes the car was driving normally, then the 4x4 light came on, followed by the transfailsafe. I've thought all along that the problem is electrical. BMW diagnosed the transfer case, but I'd had no symptoms for a failing case. Over the last week, I've been chatting with a transfer case specialist, going through various symptoms. He said today that he thinks case is fine and the fault is elsewhere. Disconnected the transmission connector, cleaned and reseated it. Abs and steering angle sensors are next on the list.

Alan Gunn · Post by **Alan Gunn** » Tue Feb 11, 2025 5:49 am

ABS then live data is where you need to look.

fatjohnny · Post by **fatjohnny** » Tue Feb 11, 2025 3:53 pm

Well, I've put everything back on under the car. Just driven it for 10km. No warning lights. Ran a live test on the wheel sensors, all stayed within a kilomètre of each other. Obviously I need a longer road test. That really leaves the SAS to check, unless anyone can think of anything else?

henrym3 · Post by **henrym3** » Tue Feb 11, 2025 8:43 pm

The fact you’ve done 10km without issue and presumably the gears changed ok suggests the fault is electrical. Maybe even fixed now. I know from experience it takes quite a few miles to get your confidence back and stop watching for a light to appear. You can check the steering angle sensor with the diagnostics 0 degrees around straight ahead and see the angle move as you wriggle the steering. Sometimes it’s difficult to find on the diagnostics tool. Your making progress though and gaining good experience.

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