Auto/Tiptronic Selection

[Garryg 5]

I'm having problems with the Auto box gear changing! When I accelaerate and it drops a gear it doesn't go up the gears again when you level out the speed...I need to put it in to tiptronic and do this manually.

Coming back from Taupo yesterday I hit a passing lane and went to pass a car, it dropped a gear but then the warning light flashed and it lost power......any ideas??

Cheers

[yng_750 247]

could be a computer issue or a fluid/valve issue

either the comp isnt telling it to change or the pump isnt creating enough pressure to activate the auto shifting

Only real option is to get it checked by a reputable gearbox specialist, not much diy available here

[jeffbebe 1559]

I'm having problems with the Auto box gear changing! When I accelaerate and it drops a gear it doesn't go up the gears again when you level out the speed...I need to put it in to tiptronic and do this manually.

Coming back from Taupo yesterday I hit a passing lane and went to pass a car, it dropped a gear but then the warning light flashed and it lost power......any ideas??

Cheers

I've had a similar problem recently but only after the car has done a hill climb in low gear; when I hit the flat again the car has remained in low gear and I've had to manually change up. My car's with my mechanic at the moment so I'll let you know what they find but as Jason says, probably something only a specialist can pinpoint.

[Allanw 1071]

I saw somewhere else about checking tyre pressures and tread - rolling circumfrerence of the tyres can trick the car into doing silly things, as it reads different speeds from different wheels.

[yng_750 247]

if an e39 detects an inaccurate reading from a wheel sensor it will light up the ASC light and generally disable traction control and cruise control and ABS the affected wheel

it shouldnt have a profound effect on your computer unless your tyre diameter front to rear is significantly different but even then unlikely

some 4WDs with active center diffs (GTR skylines etc) have a cry with staggered wheel size as it constantly thinks the front wheels are losing traction because they are turning faster

The lack of pressure can be caused by over heated fluid which may account for the failure jeffbebe had going up a hill, at any rate if your fluid is getting that bad your looking at getting a full flush at minimum.

Wouldnt be the worst time ever to consider a manual conversion if the box is packing up

[Garryg 5]

Had it in at the garage yesterday... They conected up the scanner and it showed no faults.

He did say that there was newer software for the E39, so it's booked in next Wednesday to have this put in.

I'll let you know if this has solved the problem!

Cheers

[jeffbebe 1559]

Had it in at the garage yesterday... They conected up the scanner and it showed no faults.

He did say that there was newer software for the E39, so it's booked in next Wednesday to have this put in.

I'll let you know if this has solved the problem!

Cheers

Anyone know how much it costs to do a software upgrade, or can anyone do it with the right tools?

[Garryg 5]

Anyone know how much it costs to do a software upgrade, or can anyone do it with the right tools?

Went in on Wednesday...90Mins later got it back and all seems to be sorted. it has actually made a considerable difference in a number of areas... He identified that the engine had some software change in 2003, but no similar upgrade was made to the transmission at that time...a No No.

So I now have new engine & trans software.... $195 + GST, well worth it.