Automatic transmission won’t stay in 4th gear

[Growlerbearnz]

This circuit is easier to read:
The OD cold lockout function (if fitted) simply disables the solenoid: the Water Temperature Switch is open when the coolant is cold, which prevents the OD Relay from energising. Once the coolant is warm, the Water Temperature Switch closes, which allows the OD Relay to turn on.

However my '91 Exceed didn't have the water temperature switch or relay, so maybe it's only fitted to certain models/markets.

You've replaced your solenoid with a blanking plate, so there should be nothing external stopping your transmission from shifting to OD.
Internal problems could be gunk blocking the OD/4th hydraulic control circuit, or a sticky/leaky governor outputting a low pressure which would cause the transmission to think it is travelling slower than it is.

I'd try the full fluid flush and maybe use Transmission Cleaner to help clear out any gunk. If it still doesn't shift, then I'd check the line and governor fluid pressures (workshop manual page 23-15).
The governor is relatively easy to get to if you remove the transfer case. Line pressure is more likely a problem with the main pump, which is a transmission out deal.

 

[brent]

The engine coolant temp is monitored for overdrive... same probe that controls the glow plugs.

View attachment 19579

Interesting! Hadn't seen that table before now. Still no idea where that ghost of a relay lives. @Growlerbearnz any idea where to find the overdrive relay?

 

[brent]

This circuit is easier to read: View attachment 19580The OD cold lockout function (if fitted) simply disables the solenoid. However my '91 Exceed didn't have the sensor or relay, so maybe it's only fitted to certain models/markets. I converted from automatic to manual, so I removed all the automatic wiring. No relay, no sensor in the coolant.

You've replaced your solenoid with a blanking plate, so there should be nothing external stopping your transmission from shifting to OD.
Internal problems could be gunk blocking the OD/4th hydraulic control circuit, or a sticky/leaky governor outputting a low pressure which would cause the transmission to think it is travelling slower than it is.

I'd try the full fluid flush and maybe use Transmission Cleaner to help clear out any gunk. If it still doesn't shift, then I'd check the line and governor fluid pressures (workshop manual page 23-15).
The governor is relatively easy to get to if you remove the transfer case. Line pressure is more likely a problem with the main pump, which is a transmission out deal.

Thanks

 

[brent]

This circuit is easier to read: View attachment 19580The OD cold lockout function (if fitted) simply disables the solenoid. However my '91 Exceed didn't have the sensor or relay, so maybe it's only fitted to certain models/markets. I converted from automatic to manual, so I removed all the automatic wiring. No relay, no sensor in the coolant.

You've replaced your solenoid with a blanking plate, so there should be nothing external stopping your transmission from shifting to OD.
Internal problems could be gunk blocking the OD/4th hydraulic control circuit, or a sticky/leaky governor outputting a low pressure which would cause the transmission to think it is travelling slower than it is.

I'd try the full fluid flush and maybe use Transmission Cleaner to help clear out any gunk. If it still doesn't shift, then I'd check the line and governor fluid pressures (workshop manual page 23-15).
The governor is relatively easy to get to if you remove the transfer case. Line pressure is more likely a problem with the main pump, which is a transmission out deal.

Anticipating the fluid flush I picked up some of that Liquimoly Transmission Cleaner (part# 20224 Westcan Auto Parts ~$45 for 1L). Seemed to smooth out some rough shifting but still no overdrive gear engaging. Drove it for a week then did the fluid flush yesterday. Checked the kickdown cable length, set to spec. At highway speed still revving over 3000rpm with no sign of overdrive engaging under normal conditions. Oddly managed to get it to find OD by flooring the accelerator around 90km/hr, only happened twice and would instantly pop back into 3rd gear. Played with it for about 2 hours then called it a night. Will have governor/line pressures checked when I get a chance, hopefully learn something there.

 

[13mclean]

Anticipating the fluid flush I picked up some of that Liquimoly Transmission Cleaner (part# 20224 Westcan Auto Parts ~$45 for 1L). Seemed to smooth out some rough shifting but still no overdrive gear engaging. Drove it for a week then did the fluid flush yesterday. Checked the kickdown cable length, set to spec. At highway speed still revving over 3000rpm with no sign of overdrive engaging under normal conditions. Oddly managed to get it to find OD by flooring the accelerator around 90km/hr, only happened twice and would instantly pop back into 3rd gear. Played with it for about 2 hours then called it a night. Will have governor/line pressures checked when I get a chance, hopefully learn something there.

Did this ever get resolved? Having a similar issue

 

[Critt]

I just realized I never came back and let everyone know what fixed it for me. Mine would pop into overdrive for a minute and then go right back to third and rev high. It seemed to get worse and then wouldn't go into OD at all. The OD solenoid was expensive and I heard from others that it just clogged up again not too long after replacing it. I just put a blanking plate on it and it's been running great with OD ever since. If I floor it, it will still kick down too.

 

[13mclean]

I just realized I never came back and let everyone know what fixed it for me. Mine would pop into overdrive for a minute and then go right back to third and rev high. It seemed to get worse and then wouldn't go into OD at all. The OD solenoid was expensive and I heard from others that it just clogged up again not too long after replacing it. I just put a blanking plate on it and it's been running great with OD ever since. If I floor it, it will still kick down too.

Glad that worked for you. I have swapped the solenoid and still no dice.

 

[13mclean]

@Growlerbearnz would a bad or disconnected temp sensor cause a no shift condition? Electrical diagrams hurt my brain

 

[sk66]

@Growlerbearnz would a bad or disconnected temp sensor cause a no shift condition? Electrical diagrams hurt my brain

The temp sensor provides the ground for the OD relay which sends power to the OD solenoid, which is activated by the OD switch... bad OD switch, bad OD relay, or bad temp sensor/connection, and the OD relay will get no power.

Try jumping 12v battery power to the solenoid directly to see if it clicks/actuates.

 

[brent]

Did this ever get resolved? Having a similar issue

Had the transmission looked at and then fully rebuilt.

 

[Thomascrom]

Hello everyone, I know this is a somewhat old post but I think someone can guide me to a solution, I have a Delica space gear 2.8 automatic, I have had the a/t light flashing since I bought it, it drives great but the problem is in that at 3k rpm it goes 100km/h I don't feel a 4th gear that eases the ride without having to go at high RPM

Looking for a solution by checking here, I got the error code by placing a ground cable in the scanner socket, resulting in a long light and a short light, that is, error 11, check the cables and connections and they look good, change the speed sensor And I changed the transmission oil and it's still the same.

The OD works well for me, when I attach the button to the lever it does the overdrive well, I have speed in the clouster I have no abnormalities or strange sounds, the only problem is

. Light flashing a/t always from the moment you turn the key on the car and turn it off it is always flashing.
. I don't see it grabbing 4th gear, you drive at a cruising speed of 100, 110 km/h and the rpm goes at 3k 3200k, it feels forced and therefore fuel consumption is higher

I don't know what it could be anymore.