XSeries-forum

The other day I was leaving a motorway on a 360 degree slip road the exited at right angles to the previous carriageway (above). Slip road was fairly tight curve so kept it to 50ish (speed limit 30, it was tight) when exiting there was a bus in front of me so I nailed it and all I got was rev's and no gear change. Stuck in gear I looked like a right twat as I pulled on to the hard shoulder. Display reading Trans fail Safe Mode. Switched off then fired her up and has been fine since. Any idea's?
My brother thought gearbox oil level might be low as we just went round the tightest longest turn in the county then it failed. Any idea's appreciated as don't fancy dealer prices.

Could be low oil, but as it's a sealed box it needs to be showing signs of leakage.  It could be the oil is getting bad.  How many miles in the car.

Trans Fail will usually result in gear change lockout - normally in 3rd or 5th depending upon the box type.

You could get it checked by an Indy or anyone with a code reader.  Dealers will not repair, only replace a gearbox - though they will change the fluids & filters.  A 'remanuactured' box from BMW is upwards of £5k plus labour & VAT.  Specialists will do the job for around £2-3k - assuming there is that much if a problem.

It doesn't sound very serious given it's been fine since, but a code check is worth doing.  BMW Dealers will do that for under £100 and it takes about 30mins.

Richard

Thanks Richard.
It's a 53 plate Diesel Sport, first of the facelift. So guess it's a ZF box by looking at your other posts. She has had an easy 75k miles thus far. When do oil and filters need changed, or recommended to be changed?

If you have a facelift then you should have a 6-sp ZF box.  According to BMW, these units are 'sealed for life' so they have no specified change interval.  There is a massive debate about the efficacy of changing the oil versus it stirring up debris and there being a failure afterwards.  The failures 'appear' to be more prevalent on the 5-sp.

60k miles is what BMW call the 'useful life' of a car (according to my local dealer) so a change at 75k could be beneficial, but should be done by someone who has access to the procedure for doing it and the right fluid (that is specified on a label on the box).

If the oil looks or smells burnt and is brown not pink then it could be an indication of deeper issues.  'Burnt' almost certainly means a rebuild is needed in the not too distant future as it indicates clutch material in the oil and overheating from clutch slip.  A 'code read' will indicate which set.

The filter is about £60 and the oil a little more.  Takes about an hour or two to change it all.  There are some on here who have changed it DIY and most have been fine afterwards. . If there has been a failure, it was probably on the way anyway but a fluid change was the cheapest first fix, and often works just fine.

Richard

Hi,

Outside chance theory. With a very tight prolonged bend, maybe the gearbox oil was swept to the side due to the G forces and the moving parts were temporarily starved of oil, which threw the gearbox light. Any chance you can try that bend again ? There is a reason some sumps/tanks are baffled.
Potentially you also have a low gearbox oil level. Mine was low and there was absolutely NO sign of any leak anywhere so can only surmise it was underfilled at the point of manyfacture.

Just my thoughts,

Regards,

Nat.

So after a few weeks of running fine, it happened again. Transmission Failure Failsafe mode came up, stuck in gear. Switched off switched on ran fine.
Friend is an AA Man, very friendly too. He plugged in and it showed a Tran Lever position sensor failure. Can't mind the code. We have checked connections on either end gave them a clean and spray and so far so good, but fully expect it to reappear.
Has anyone had this problem, if so what did you do?
I will post the fault code when I get back to Scotland on Thu. Don't worry I flew to London.

So the fault code is P0705 Transmission Range sensor "A" circuit malfunction (PRNDL input).
We have checked and cleaned the connections at the shifter end and gearbox end. It's not happened since but I don't think for a moment that has cleared the fault.
Any ideas?

Could be the shifter itself is failing.  It's supplied as a single part if memory serves......so not a cheap fix

Richard