I have a 1997 Jap import Navarra Ute it is automatic shift with overdrive. Once warmed up the overdrive is selected at GPS 102 km per or when you decelerate. Is it possible to adjust the overdrive selection so that it (the overdrive) is selected at a lower speed say 95 kmh.
doug207,
May 9, 1:50am
Service the gearbox.
nx,
May 9, 2:50am
Has done this from day one before and after service
mm12345,
May 9, 3:25am
The torque converter lock-up (AKA overdrive) is probably controlled by a TCU which reads engine RPM and throttle position (and other stuff).Perhaps the throttle position sensor is out of whack.I would expect that overdrive should kick in on low accelerator with a warm engine at 50 km/h or thereabouts - not until it's doing over 100km/h. Considering the amount of fuel you're probably wasting, it would be worth getting this diagnosed properly and fixed - it's probably not a transmission fault per se, but a sensor or TCU issue.
tonyrockyhorror,
May 9, 4:56am
Quite possible it's running too cold (engine) and torque convertor lock-up is inhibited until a certain rpm to prevent labouring the 'cold' engine.
nx,
May 9, 6:14am
temperature guage runs at between 8 and 9.Have been assured that thisis within the normal operating range.
mm12345,
May 9, 11:01am
AFAIK, the temp lockout only disables OD completely - it's either on or off, so it's not going to cause an issue with OD only working above 100km/h. FWIW, the temp sender used by the dash gauge may not be the same sender as the TCU/ECU uses.
It may be in the service manual above. Frontier/Navara are the same vehicle.
motorboy2011,
May 9, 9:40pm
not sure on yours, but my nissan has 2 temp sensors, one for the gauge and one for the ecu, your ecu one might be faulty and therefore thinks the engine is still cold. Trans on mine locks at approx 60-65 on light throttle.
kwkbrk,
May 9, 9:59pm
O/D and lock up converter are not the same thing surely ! And the lock up converter is never going to engage until the car is at open road revs / speed, and has nothing to do with temperature !
mm12345,
May 9, 10:12pm
"OD" on conventional (slush box) autos is torque converter lock-up. It's usually programmed so lock-up will not engage until the car is at normal operating temperature range.So a stuck open thermostat is a common cause for OD not to engage. OD usually engages, when at normal operating temp, at low throttle setting at speeds perhaps 50km/h or more.So the control unit must sense speed, revs, and throttle setting.If something goes wrong then OD won't engage.
tonyrockyhorror,
May 10, 4:32am
It has everything to do with temperature.
mm12345,
May 10, 5:04am
They probably also tend to envisage it as "overdrive", as that's what the button on the gear selector of many such equipped cars says - "O/D". Does it mean that gearbox output shaft rotates faster than the engine crankshaft!Who cares!
tonyrockyhorror,
May 10, 5:20am
Not me. It's not relevant.
mm12345,
May 10, 5:24am
No, but he did mention that it was a '97 Nissan, and that's what they tend to have - an "OD" button.
As you seem to be so clever and pedantic, why don't you explain for us what overdrive is, and why anybody driving a modern auto car should care a flying feck.
tonyrockyhorror,
May 10, 5:26am
Why would I bother! It has no relevance.
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