Automatic not selecting overdrive :(

[cresta]

I have had this problem with my auto for a long time now and it's finally pushed me over the edge -_- my auto will not select overdrive except for the rare occasion. I believe it's the auto from a Soarer to fit my 1jz, but previous to the swap I was still having the same drama. Because of this I am thinking the mechanic didn't actually swap the box at all. The diff in it is also real noisy, not sure if that can cause any issues. If anyone knows this problem please help!

[dumbass]

no overdrive normally means wiring problem or ecu
overdrive works when no power gets to the solenoids in the box

[maj]

Transmission fluid not getting up to temperature perhaps? If it's sometimes selecting but other times not, then usually indicative of a problem in your cooling system.
Also solenoid may be on it's way out.

[dumbass]

there is no solenoid to trigger over drive on a 1j box
solenoids control 1st 2nd and 3rd then when they turn off u get overdrive
not sure if this is a conversion but maybe overdirve switch aint wired up
also some boxes have a temp sensor so u might be right in oil temp as if ecu
is reading oil temp is cold all the time then it might stay out off overdrive

[cresta]

Well I took it to an auto place and apparently no speed sensor or any sensor for that matter is plugged up -_-

[ivandude]

Also if youre wanting to treat the auto well , seeing as you are diagnosing it and fixing it up , give it a separate transmission cooler will improve the life of your auto a lot, and only costs like $100 for a kit to fit one.

[cresta]

Also if youre wanting to treat the auto well , seeing as you are diagnosing it and fixing it up , give it a separate transmission cooler will improve the life of your auto a lot, and only costs like $100 for a kit to fit one.

Already has one, fuck it... Bought a manual box and going manual. This will fix my problem

[Z2TT]

Check that all Water Temperature sensors on the Engine are working to spec, some ECU's may rely on the water temp as an indication of how long it has been since the engine was started.

[4th surf]

This is a common problem and what happens is to put it simply the ECU has died or is dying. The capacitors in it reach the end of their useful life. leak and then degrade the tracks on the motherboard. Then what happens is you loose overdrive/lock up, then get slow/rough shifting and a power loss from the engine. Solenoid gone in the auto you tend to loose first gear and the only way to confirm that diagnosos is as set out in the factory manual is to manually shift it from 1st to see if all the gears are there up to 3rd

[cresta]

This is a common problem and what happens is to put it simply the ECU has died or is dying. The capacitors in it reach the end of their useful life. leak and then degrade the tracks on the motherboard. Then what happens is you loose overdrive/lock up, then get slow/rough shifting and a power loss from the engine. Solenoid gone in the auto you tend to loose first gear and the only way to confirm that diagnosos is as set out in the factory manual is to manually shift it from 1st to see if all the gears are there up to 3rd

Well, when I put it in 1st it seems normal but as you get to like 20km/h over it will slip into second. then as you slow down it will harshly drop into first.

[maj]

Does the transmission have a control cable, or possibly relies on the throttle cable/TPS, or even both.

On mine if you didn't have the control cable or throttle properly adjusted, it gives you harsh shifts and occasional slip before disengaging/shifting. Also sometimes shudder on takeoff in 1st.
BGB showed the proper way to ensure it was adjusted.

[Z2TT]

Transmission ECU Relies on Speed and Throttle Position Mainly.

Capacitor Problems is common mostly in JZA70 1JZ and Early 1UZ.