Transmission moving only in reverse

Hi,

I don't suggest removing it when hot. What is the condition of the transmission fluid? Is it clean and full? Also, when you checked for codes, did you use a scanner that can read transmission codes?

Let me know. Also, when the engine was revving high before shifting, was the vehicle still accelerating, or did it seem the transmission was slipping?

Let me know.

Joe

Hi,

This could be multiple things. Since there are no codes, I would likely start with confirming if line pressure is where it needs to be. The interesting thing is drive (low) and reverse work off the same clutch. If you place it in low gear (1), does it move?

Take a look at the pics below. They provide directions for performing the line pressure testing. Try this and let me know the results.

Take care,

Joe

See pics below.

Hi,

That is a standard on automatic transmissions, at least any that I've ever taken apart. Take a look below at a pic for the friction plates on this vehicle.

Joe

Hi,

At this point, since it works in reverse and not in drive or low gear, I feel we need to check the line pressure to see if there is an issue.

I attached the directions above. Let's see if the pressure is low.

Take care and let me know what you find.

Joe

Let me know what you find. Also, if I don't hear from you for a few days, I wish you and your family a Merry Christmas.

Take good care of yourself.

Joe

Hi,

Since there are no codes, this is where I would start. You could take things apart and confirm that shift solenoids, valves, are working, there are no obvious wiring issues, and the valve body is clean and nothing is sticking. However, that is a lot of work and very time-consuming, and may not indicate the issues.

Tell me, does it have an external tranny cooler? If you lift the drive wheels off the ground and place it in drive, does it do anything?

This is an electronically controlled transmission that electrically controls the line pressure, throttle pressure, lock-up pressure, and accumulator pressure, etc, through the solenoid valve. If I had to guess, that is what I feel has failed. However, it requires removal of the valve body to access and I'm not sure that is the cause. That's why I wanted to check the pressure.

I attached two pics below showing the location of the solenoid valve (SLT) location. I didn't highlight the DSL solenoid because it is responsible for reverse (working). However, that is why I asked about placing it in low gear. IT controls that as well. But, since we have reverse, that is why I feel it is a line pressure issue.

Let me know your thoughts.

Take care,

Joe

See pics below.

Hi,

You are never a disturbance. And I hope you had a great Christmas. I listed what the solenoids are for below. I also attached a pic identifying all of them.

SLT - The linear solenoid valve (SLT) controls the transmission line pressure for smooth transmission operation based on signals from the throttle position sensor and the vehicle speed sensor. The ECM adjusts the duty ratio (*) of the SLT solenoid valve to control hydraulic line pressure coming from the primary regulator valve. Appropriate line pressure assures smooth shifting with varying engine outputs.

SL1 to SL4, SL, SR - Shifting from 1st to 5th is performed in combination with "on" and "off" operation of the shift solenoid valves SL1, SL2, SL3, S4, and SR which are controlled by the ECM.

DSL - The shift solenoid valve DSL is turned "ON" and "OFF" by signals from the ECM in order to control the hydraulic pressure operation, the lock-up relay valve, which then controls the operation of the lock-up clutch.

I attached a pic below identifying all of them. By accident, I cut a few off on the pic I sent yesterday.

I hope this helps.

Take care,

Joe

No problem. Let me know what is found or if you have other questions.

Take care,

Joe

Hi,

If you look below, I reattached the fourth pic from the original ones I sent. Let me know if that is the one you are referring to and if it is readable. When it is being sent, it is clear, so let me know if it is on your end.

As far as the transmission type, if you open the driver's door, there will be a label. If you look at the bottom left of the label you will see A / TM. That is the axle and transmission types. The first number is the axle and the second is the transmission model. See pic below.

Toyota / Lexus is one of the few companies that provide that info in an easy to find location.

See pic below for example.

I hope this helps.

Take care,

Joe