Another gearbox query!!!!

[Johnny-p]

I'm hoping someone may be able to shed some light on this please..

A couple of weeks ago I had the dreaded "trans fail safe" error pop up..

Pulled over a couple of miles down the road and remembering what I've read on here before just turned her off for a couple of mins,restarted and all was good again..

I've had no problems since even towing my caravan.....UNTIL this weekend!!!!

I was going down a fairly steep road and I got a harsh jerk as it moved down a gear and then back up almost straight away then all back to normal again..

It has been driving fine till today.

Again driving down a steep but not too steep hill and it did the same again but this time it went down up down as if it couldn't decide which gear it should be in again it has driven fine since????

Now thinking back to when the trans fail safe happened I was driving uphill-coincidence???

Going to get the codes read at my Indy on Friday but was wondering if anyone has had similar faults..

Could it be something as simple as low ATF??

TIA John..

[X5Sport]

Were you holding your speed down on the brakes?  30mph by any chance?

If so the gear change is completely normal.  The box will go to 3rd at certain speeds if going downhill and gentle braking is being used.  It is designed to provide more engine braking (autos used to be bad at this) and as soon as you apply even gentle throttle again the box changes back to normal 4/5/6 or as it needs.

Richard

[Johnny-p]

Hi Richard

The first time it happened I was doing about 50 and the lurch was so harsh that I thought I'd lost drive completely until it up changed again..

But yes when it happened again last night I guess it was about 30ish...but still quite violent..

When I get the codes read Friday I'm going to get him to check ATF and trans box fliud levels aswell..

Off to France next week and don't need the ol girl breaking down over there!!

[X5Sport]

I remember mine being quite harsh when it enabled too.  It always did it in a 30mph limit coming out of Cranfield towards Bedford on a steep hill.  As soon as the throttle was applied the box changed to 4th or 5th very smoothly.

It might well have done it at other speeds too if the brake was applied gently to hold the speed.  After a few seconds the box would shift abruptly and engine braking took over.  The function has a name but I can't remember it.

My X6 does it too, but with 8 gears it's much less 'abrupt'.

[petert]

I agree with Richard - had this many times on my 2004 3.0i 5 speed.
Not noticed it on my 2010 35d but then there aren't that many hills where I live in Ontario!
Peter T

[RoShamBo]

Hi Johnny

I had the Trans Failsafe Prog error pop up from nowhere a week ago on my 4.4i Sport.
Doing lots of homework it seems many things - even pretty minor things can trigger this error - too many to list - even a weak battery can do it apparently. So get the codes read and that should point to the problem.
In my case - it was a worn cam cover gasket seal allowing oil onto the spark plugs, triggering the error.

This was fixed today actually and I am just about to take the car out to see if its fully fixed the problem.

Good luck with the diagnosis & hope you get it sorted for your trip to France !

Ro.

[Johnny-p]

UPDATE

Just got back from my Indy and there was a fault logged on the downshift from 4th to 3rd gear..

He also took a sample of my ATF and it looked in poor shape and the filter was probably the same and had never been changed it's @123k at the moment..

He said he's seen this many times and new oil and filter would cure it..

Whilst he's under there I'm getting the transfer box oil done aswell..

Fingers crossed that's all it is :'(