Mazda auto not shifting into OD

Honest John Back Room » Technical matters
View Threaded
Wed 1 Dec 2004 14:48
Mazda auto not shifting into OD - In Theory
My 626 auto shifts smoothly up to third, but will rev up very high before flinging itself into 4th/OD. On the motorway yesterday, it remained in third at 4000 rpm for most of a two-hour journey, occasionally moving into OD only to downshift a few seconds later for no apparent reason. Any ideas what could cause this? It happened regularly last winter, as well, but the problem vanishes in warmer weather. I don't see how the seasons would affect the transmission, but it is the only factor I can identify. It is a 1990 626 2.0 auto 12v. The car has 110k miles. I am led to believe it is a Ford auto box, but don't know for sure. Thanks in advance for any adivce.
Reply | Report as offensive | Link
Wed 1 Dec 2004 19:42
Mazda auto not shifting into OD - T Lucas
With a Mitsubishi autobox there is a temperature sensor that stops the 'box going into topgear and lockup mode.This would make sense as your probs occur when the temp is cold.
May well need to get it plugged into a diagnostic tool,on a Mitso it's a handheld diagnostic,so that you can drive along and see what the temps are and at what speed the gears change.
With a Mitso the part is about £40.
Reply | Report as offensive | Link
Thu 2 Dec 2004 08:26
Mazda auto not shifting into OD - In Theory
Thanks for the info and advice. I suspected that the engine was Mitsubishi, but not the transmission. Useful to know. Also makes me wonder what it means to drive a 'Mazda'!
Reply | Report as offensive | Link
Wed 8 Dec 2004 00:31
Mazda auto not shifting into OD - Pete M
Aha! I had exactly this problem some years ago in a 2.0 12v Ford Telstar, which is exactly the same as a 626.
The problem was that the engine thermostat had stuck open, so the engine was taking so long to warm up that the box refused to change into O/D.
These cars are all Mazda, even the Ford badged ones we had out here in New Zealand and Australia.
Check to see if your thermostat is working correctly, then check the temp sensor for the gearbox. Shorting out the connector should allow it to change into O/D at any temperature.
I think the sensor is there to prevent the engine from dropping into O/D when it's cold and 'lugging' which probably causes excess pollution.
Reply | Report as offensive | Link
Wed 8 Dec 2004 12:45
Mazda auto not shifting into OD - In Theory
Thanks for that, Pete. The car is in for service in a couple of weeks, so I will have the mechanic give it a look. The engine has been running suspiciously cool for some time, so the thermostat seems like a likely culprit. Normally, the temp guage climbs gently to the half-way point and then sits there like it has been riveted. Now it rests a fair bit lower, even after a stop-go journey around town.
Reply | Report as offensive | Link

We give you the low down on how to save on insurance, little-known tricks and tips, what insurance groups mean and how to use insurance aggregators to beat insurers.

Insurance group finder and how to save on insurance