What controls lock up/unlock on a hydraulic a442f (4 Viewers)

[Dusten]

Basically the same as the a440f in function.

I've noticed when it's cold, on the first drive occasionally the transmission won't unlock the converter unless I drop it manually to 3 or N. Meaning as it slows it's not unlocking.

To add to this, it only does it once. And if the converter is locked and you force it to unlock, it won't do it

 

[ThreeEyedBandit]

If it's a 1fz-fe the ecu controls it via a solenoid in the pan.

Diesels have a different A442, not sure on them.

 

[Malleus]

The A440F and the A442F are completely different transmissions.

The A440F is controlled by a hydraulic governor mounted at the rear of the transmission, in concert with the shift cable and the shift lock-up signal valve in the rear valve body. Additionally, the torque converter has a sprag clutch (also known as an over-running or one-way clutch), which controls the actual locking action of the torque converter, based on the fluid flow inside it.

The A442F is not hydraulically controlled, as @ThreeEyedBandit mentioned above, although the throttle cable is still used to set the fluid pressure. The shift lock solenoid controls the shift valve, in place of the governor used in the A440F. As in the A440F, the torque converter is fitted with a clutch to lock its separate halves at speed.

 

[Dusten]

The A440F and the A442F are completely different transmissions.

The A440F is controlled by a hydraulic governor mounted at the rear of the transmission, in concert with the shift cable and the shift lock-up signal valve in the rear valve body. Additionally, the torque converter has a sprag clutch (also known as an over-running or one-way clutch), which controls the actual locking action of the torque converter, based on the fluid flow inside it.

The A442F is not hydraulically controlled, as @ThreeEyedBandit mentioned above, although the throttle cable is still used to set the fluid pressure. The shift lock solenoid controls the shift valve, in place of the governor used in the A440F. As in the A440F, the torque converter is fitted with a clutch to lock its separate halves at speed.

It is on the JDM diesel. I've tried explaining this before. Someone always tells me the a442f is different and then they learn.


The JDM diesels with the 1hdt got a hydraulic a442f similar to the a440f.

 

[Dusten]

If it's a 1fz-fe the ecu controls it via a solenoid in the pan.

Diesels have a different A442, not sure on them.

I have a diesel. The trans is hydraulic. No electronics at all.

 

[Malleus]

Maybe it woudl help if you expounded on that in your original post, since all the diesel Land Cruisers are imports, and therefore not what most people have, or have experience with.

 

[Dusten]

Maybe it woudl help if you expounded on that in your original post, since all the diesel Land Cruisers are imports, and therefore not what most people have, or have experience with.

This is why I mentioned it's identical in function to the a440f

 

[Dusten]

After reading your post on the a440 and several other posts in the 60 series forum, I believe that either my throttle cable is an issue or my throttle valve is sticking, I'm going to leave towards the throttle cable. When I have the transmission rebuilt the shop broke the factory cable and I believe replaced it with an aftermarket one, I am going to order a factory one from part suit and replace it here shortly and if the issue continues I will then pull the throttle valve and clean it

 

[Squash]

The A440F and the A442F are completely different transmissions.

The A440F is controlled by a hydraulic governor mounted at the rear of the transmission, in concert with the shift cable and the shift lock-up signal valve in the rear valve body. Additionally, the torque converter has a sprag clutch (also known as an over-running or one-way clutch), which controls the actual locking action of the torque converter, based on the fluid flow inside it.

The A442F is not hydraulically controlled, as @ThreeEyedBandit mentioned above, although the throttle cable is still used to set the fluid pressure. The shift lock solenoid controls the shift valve, in place of the governor used in the A440F. As in the A440F, the torque converter is fitted with a clutch to lock its separate halves at speed.

Diesel Hdj81/hdj80 early model.
There are two A442f transmissions.
One hydraulic till sometime in 1992.
A442f with solenoids 1992 onward.
Also a model with cruise control and one without.
Transmission will not go into 4th gear until it meets a certain temperature.
Here is a valid part number for a DIESEL rebuild kit. Supposedly does a440,A442F etc
Transtar 137006AF. There are additional components available, and they can rebuild your torque converter.
Transtar Canada or US.

 

[Cruisers and Co]

Diesel Hdj81/hdj80 early model.
There are two A442f transmissions.
One hydraulic till sometime in 1992.
A442f with solenoids 1992 onward.
Also a model with cruise control and one without.
Transmission will not go into 4th gear until it meets a certain temperature.
Here is a valid part number for a DIESEL rebuild kit. Supposedly does a440,A442F etc
Transtar 137006AF. There are additional components available, and they can rebuild your torque converter.
Transtar Canada or US.

There’s 3 generations of 442’s in circulation

-Full hydraulic in early HDJ’s until 92
-4 solenoid w/ throttle cable (kickdown cable) (93/4 fzj’s and other models)
-And a 5 solenoid that came behind I believe FT’s but for sure behind FTE’s

Cable and 5th solenoid control line pressure.


Sorry OP not much help

 

[obe12]

Basically the same as the a440f in function.

I've noticed when it's cold, on the first drive occasionally the transmission won't unlock the converter unless I drop it manually to 3 or N. Meaning as it slows it's not unlocking.

To add to this, it only does it once. And if the converter is locked and you force it to unlock, it won't do it

I dont know if you have figured out the TCC unlocking issue or not. The 442F need Idle Switch info and Brake ON switch info. I didn't read if what year truck you have, possible Trans Diagnostics when I happens show a code Via Flash the OD lamp. The 4 solenoid version A442F has an OFF ON signal to the solenoid, the truck if I remember has to be in 3rd gear or OD to lockup the converter aka GAS model. TPS adjustment could possible create this issue, why cold one time than normal... leans more to inside the transmission but I would check this other stuff before I dove into pulling the Pan or Trans Out

 

[Dusten]

I dont know if you have figured out the TCC unlocking issue or not. The 442F need Idle Switch info and Brake ON switch info. I didn't read if what year truck you have, possible Trans Diagnostics when I happens show a code Via Flash the OD lamp. The 4 solenoid version A442F has an OFF ON signal to the solenoid, the truck if I remember has to be in 3rd gear or OD to lockup the converter aka GAS model. TPS adjustment could possible create this issue, why cold one time than normal... leans more to inside the transmission but I would check this other stuff before I dove into pulling the Pan or Trans Out

Should have read what truck I have.



None of that applies. My a442f has zero electronics.

No overdrive switch.
Lockup is only in overdrive
No tps

 

[obe12]

Should have read what truck I have.



None of that applies. My a442f has zero electronics.

No overdrive switch.
Lockup is only in overdrive
No tps

Why I said quote : I didn’t read what If what year truck you have”

And

“if you have The 4 solenoid version A442F“ because your thread didn’t specify what exactly A442F you were working on. To share with others with a 4 Solenoid version what the possibilities could be. Just happens to be multi-able types.

Sorry for the misunderstanding!