Transmission (722.6) won't kick down

[hygt2]

Driving home last night from North East London, I drove very sedately from start for about 15 miles between 40 to 60mph and getting about 42 mpg.

When I got to the slip road to join A13 outside Canary Wharf, I wanted to accelerate up the ramp but the gearbox won't change down or kick-down at all, even when the kick-down switch was depressed. The car accelerated up the ramp at 1000 rpm in 4th gear from 30mph with the torque converter appeared to be locked on nearly full throttle.

Normally the gearbox would change down 1 or 2 gears when the throttle is gradually depressed and full kick-down of maybe 3 gears can be achieved through the kick-down switch.

I switched off and restarted the car at the next red traffic light and the gearbox behaved normally again.

No limp-home mode, no mis-fire and no engine lights.

Any ideas what was going on and why it did that?

 

[ABBY]

has transmission been serviced? oil and filter change? fluid leak on electrical connector?coolant contamination?
Abby

 

[Buggerlugs]

Did the car shift normally otherwise? I mean, was it just no kickdown or did the gearbox hold onto 4th till the traffic lights when you recycled the ignition?

 

[GH421]

maybe a speed sensor on the gearbox

 

[markmifsud]

Check the ATF level first, then I guess you better get the codes read

 

[hygt2]

has transmission been serviced? oil and filter change? fluid leak on electrical connector?coolant contamination?
Abby

The torque converter was changed 10k ago so fresh oil and filter back then. Leaky plug changed as well.

No coolant contamination - it's a Berg radiator.

 

[hygt2]

Did the car shift normally otherwise? I mean, was it just no kickdown or did the gearbox hold onto 4th till the traffic lights when you recycled the ignition?

The box shifts down when slowed but would not down shift on part or full open throttle.

I wonder if it is related to the possible alternator problem which started yesterday?

 

[Buggerlugs]

Is it still doing it or was it just the once?

 

[hygt2]

Just once but my car is not working right now

 

[BlackC55]

Maybe its a lack of power issue (engine) not a gearbox one.

 

[hygt2]

Maybe its a lack of power issue (engine) not a gearbox one.

Something to do with the alternator about to pack up?

The alternator packed last night, 3 days after I notice the kick down issue)

I did noticed that when I was about 20 seconds to the complete breakdown last night, the car won't shift out of first gear.

 

[Buggerlugs]

There is certainly a connection between the alternator and the gearbox, the TCM doesn't like low batt voltage and will adopt either a failure management mode or a full limp mode depending on the severity of the problem, so it's new alternator time for a start then......