Auto box change up
Posted: Sat Feb 09, 2008 6:15 pm
I've been bleating on about my autobox holding onto gears a little bit too long and kickdown happening too early so I thought I'd better do something about it. Changing the gearbox oil and cleaning the filter last year really helped a lot but it still downshifted 2 gears at a time at inopertune moments, resulting in a lot of revs and getting nowhere fast when overtaking
On the fuel pump there's a Throttle Positioning Sensor which signals the autobox change up times depending on throttle position.
Mine was set quite far to the clockwise position of the adjustment so I marked the position, loosened the screws and turned it about 2mm anticlock - tried the Bongo and found I had turned it too far - it wouldn't kickdown above 60mph.
Turned it back 1mm and tried again. Seems to be good now - the upchanges on light throttle are smoother and earlier (but still revs to 4500 before changeup on full throttle) and doesn't drop 2 gears when kickdown is demanded at 60 mph.
I'm sure there's a setting somewhere for the TPS by using an ohmeter but I can't find it.............


On the fuel pump there's a Throttle Positioning Sensor which signals the autobox change up times depending on throttle position.
Mine was set quite far to the clockwise position of the adjustment so I marked the position, loosened the screws and turned it about 2mm anticlock - tried the Bongo and found I had turned it too far - it wouldn't kickdown above 60mph.
Turned it back 1mm and tried again. Seems to be good now - the upchanges on light throttle are smoother and earlier (but still revs to 4500 before changeup on full throttle) and doesn't drop 2 gears when kickdown is demanded at 60 mph.

I'm sure there's a setting somewhere for the TPS by using an ohmeter but I can't find it.............
