Dieselchessy
New member
O/D is just 4th gear. They call it over drive because the ratio is taller than 1:1.
The TC locking up is a different thing than the tranny shifting in and out of 4th gear.
P0770, Shift Solenoid E
- Thread starter Stereww
- Start date
O/D is just 4th gear. They call it over drive because the ratio is taller than 1:1.
The TC locking up is a different thing than the tranny shifting in and out of 4th gear.
O/D feels like a 5th gear right? If I'm in 4th and hit the button to turn O/D on and the RPMs drop wouldn't that mean the TC locked?
Dieselchessy
New member
The O/D button doesn’t lock the TC, it makes available 4th gear.
With O/D off your tranny will be a 3 speed with third gear being 1:1. This is the best position for heavy work as it works the tranny the least.
The rpm drops when you turn O/D on because the tranny shifts to 4th.
I don’t know how to explain to you what it feels like when the T/C is locked. It should lock in 3rd or 4th I believe.
The tranny controll module would use the brake pedal, TPS, TV cable, vehicle speed to decide to lock the TC.
Is all that in proper working order?
This has really got me confused now. Thanks for taking the time to explain. I've been driving around for the last couple days with O/D off just to see what happens, still no CEL. So that "solves the problem". Whatever that means, kind of expected I guess.
Its making more sense now. So when I hit O/D on, the RPMs drop as the tranny goes into 4th.
Would I know it's going into O/D if I could count the "shifts"?
Could I feel 5 shifts? 1st, 2nd, 3rd, 4th and O/D?
As for the TPS, I'm not sure. Obviously I just had my hands on the cable, seemed good to me.
Knowing now though that with O/D off I'm limited to 3rd gear. The different ratio in 4th is making me wonder if that's causing the code? Could the transmission control module be confused with the different ratio and because of that different ratio a different speed at a certain number of RPMs?
Sent from my Pixel 3 XL using Tapatalk
19963.4lsr5
New member
The trans has 4 forward gears. It only shifts 3 times.
1) into 2nd
2) into 3rd
3) into 4th
Then the torque converter locks up and gives the final rpm drop.
Sent from my iPhone using Tapatalk
1) into 2nd
2) into 3rd
3) into 4th
Then the torque converter locks up and gives the final rpm drop.
Sent from my iPhone using Tapatalk
Dieselchessy
New member
4th and O/D are one in the same.
So the theory being the TCM is expecting a certain RPM from the engine for a certain tranny output speed. And due the different 4th gear ratio, the TCM flags the TC error thinking there is an issue.
I honestly don’t know. Never been involved with a tranny gear ratio change.
19963.4lsr5
New member
Like Diesel says.....suggested....
You need to verify your TC is locking up. Easiest way to do this is to drive above 50mph on a flat road and give it a little more throttle. It the RPMs rise instantly it’s not locked up. If the RPMs and speedo rise together it’s locked and the code is being generated from the ECU not seeing the correct rpm.
If driving it around with OD locked out keeps the code from appearing then the different ratio is causing the code. I’m sure it’s 1:1 just like the American version.
Sent from my iPhone using Tapatalk
You need to verify your TC is locking up. Easiest way to do this is to drive above 50mph on a flat road and give it a little more throttle. It the RPMs rise instantly it’s not locked up. If the RPMs and speedo rise together it’s locked and the code is being generated from the ECU not seeing the correct rpm.
If driving it around with OD locked out keeps the code from appearing then the different ratio is causing the code. I’m sure it’s 1:1 just like the American version.
Sent from my iPhone using Tapatalk
Would I be causing damage either way? If the TC is locking up am I all good to ignore it? If it's not locking up, is that something I need to solve?
Sent from my Pixel 3 XL using Tapatalk
Dieselchessy
New member
I think you need to address it with a professional with the proper equipment to fully diagnose the issue.
Thanks for all your help, I'll continue to update you.
Sent from my Pixel 3 XL using Tapatalk
Malinoas38
New member
Do you have an update?
Very curious, as I am having similar issues & not sure how to address.
Thanks!
fwiw, I chased this issue for a long time. Although it kept throwing the code, it drove fine and I never experienced any real drive- or shift-time symptoms.
Originally, I started with the throttle position sensor. I cleaned the connector and used some silicone dielectric. That actually solved the problem for a long time. When it started popping up again, I eventually replaced the solenoid. Somewhere along the way I had to replace the TPS sensor as well but not because of this code.
Long story short, if the solenoid is new, consider working backwards and check the other inputs like the TPS sensor.
Originally, I started with the throttle position sensor. I cleaned the connector and used some silicone dielectric. That actually solved the problem for a long time. When it started popping up again, I eventually replaced the solenoid. Somewhere along the way I had to replace the TPS sensor as well but not because of this code.
Long story short, if the solenoid is new, consider working backwards and check the other inputs like the TPS sensor.
Last edited:
Dan MacMedan
New member
So should I guess I should assume if my 3rd gen has 404,000 miles on it, this would be the lock up clutch finally wearing out and not electrical. HAHAH
