Hi, I have a 1998 V70, 2.5, 20v auto, petrol non turbo. I always have the auto gearbox in "economy/" mode. When reaching 50mph at about 2,000 revs the gearbox changes into 4th gear and revs drop to about 1,750.I think its the torque converter locking up.
A couple of days ago the gearbox changed as usual but immedietly the revs increased to about 2,200 and within a second changed again and revs dropped to 1750. This happened constantly until I increased my speed to about 60mph when it remained in 4th gear.
I drove about 20 miles and before my return journey I put g/box into "sport" mode and the box changed fine without surging.
The box is quiet and smooth at all times. The g/box oil if full and clean.
My first thought was a faulty g/box/ torque converter but given the problem is eradicated by placing in "sport" mode I wonder whether its an electrical fault.
I would very much appreciate opinions please. thanks jack.

 

Sport mode just changes a bit in the computer. I don't see how it could fix an electrical problem.

 

Hi firebirdparts, thanks for that. Are you saying that the fault is machanical rather than electrical. A change in g/box mode to "sport" eradicates the surge.thanks jack

 

It seems likely to me, but you might have an electrical problem that is simply intermittent.