1990 corona st170 transmission worries - Toyota Nation Forum : Toyota Car and Truck Forums

shikira57 · 01-03-2004, 09:21 AM

Transmission problems! Why does my 3 speed transmission seem to have 4 gears? Could this be because the overdrive is always on and it is acting like a 4th gear? It changes to third at the right time and revs then when you lift your foot it changes into a 4th gear. If this is an overdrive why does it not turn off with the switch on the gead lever? Could there be a wire off? This cant be good for the engine to be in overdrive while driving around town.

90CamryDx3SFE · 01-04-2004, 12:11 AM

Actually it's better to have the car in Overdrive at all times, because you're not only saving on the engine, and fuel usage, but also the Tranny.

If you switch off the O/D, you should be able to tell that the tranny is only going through 3 gears. Get the car up to about 50, or 60 mph, and then turn off OD, and see if you notice the engine increase revs like it just downshifted.

Nick · 01-04-2004, 12:17 AM

overdrive is good, unless you're towing heavy stuff, or running an auto cross or something (keeps you at higher rpm, closer to the powerband)

either the button is messed up, or what you're feeling is the torque converter "locking up" , this is pretty normal with most automatics

90CamryDx3SFE · 01-04-2004, 12:24 AM

^^ Like he said.

I forgot to mention that the reason Overdrive is there is to prevent shifting to 4th, and creating more torque...

They should really start making it opposite. Like OD off, actually means the car will engage 4th gear (What would currently be OD on in our cars), and then make OD on be when the gears won't go past 3rd (What is currently known as OD OFF for us).

Yeah... just a though :P

shikira57 · 01-08-2004, 03:25 AM

thank you for that info about o/d. We still would like to turn it off and on because the car seems to labour at 80 kph. Also sometimes tow stuff. Had a look at the wires in the gear shift and its all ok so it must be something at the other end wherever that is. Hey at least I found out what a catalytic converter is. Any ideas on how to reset one of them where a "helpfull person" put 96 in the tank and the engine is not idling when hot or at low revs.