Previa Gearbox Woes

March 27, 2005

Hi all...

Yesterday my 91 Previa 2.4 GL Auto stopped changing down...

It seems to change up OK (might be a little rapid through the gears, but I could be being paranoid now...)

There seems to be no auto changedown at all...

(Except when slowing to a stop, when it seems to end up back in 1st...)

No changedown when accelerating, not even kick-down is working...

No changedown on hills, no matter how steep...

The ATF was changed last August and has covered about 6,000 miles since...

I checked the level yesterday (hot) and it needed about 6 fl oz to top it up to the mark... hardly worth mentioning...

I can change down manually and the convertor locks up fine when using lower ratios downhill... Previous to this problem, the change has been smooth and hassle-free... When I changed the fluid, I removed the G/B sump pan cleaned it out - no swarf or metal debris at all... nice new gasket on replacement and it appears to be leak free still...

O/D still switches in/out OK and I've used the Haynes to check any fault codes from the Diagnostic socket (using O/D lamp) - no error codes, just 2 flashes per second, indicating normal status...

I have found some info on fault-finding auto boxes and that suggests that the ECU or vehicle wiring is at fault... anybody have any clues here?

TIA

Jeff

June 23, 2005

:ffs:

Hi all...
Yesterday my 91 Previa 2.4 GL Auto stopped changing down...
It seems to change up OK (might be a little rapid through the gears, but I could be being paranoid now...)
There seems to be no auto changedown at all...
(Except when slowing to a stop, when it seems to end up back in 1st...)
No changedown when accelerating, not even kick-down is working...
No changedown on hills, no matter how steep...
The ATF was changed last August and has covered about 6,000 miles since...
I checked the level yesterday (hot) and it needed about 6 fl oz to top it up to the mark... hardly worth mentioning...
I can change down manually and the convertor locks up fine when using lower ratios downhill... Previous to this problem, the change has been smooth and hassle-free... When I changed the fluid, I removed the G/B sump pan cleaned it out - no swarf or metal debris at all... nice new gasket on replacement and it appears to be leak free still...
O/D still switches in/out OK and I've used the Haynes to check any fault codes from the Diagnostic socket (using O/D lamp) - no error codes, just 2 flashes per second, indicating normal status...
I have found some info on fault-finding auto boxes and that suggests that the ECU or vehicle wiring is at fault... anybody have any clues here?
TIA
Jeff
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