i hv the same problem 7fguc 25 no F/R. I toke the valve body out. and seem to solenoid. it's solenoid ? any one can help pls.

I read your response about the seat switch issue if mast functions were disabled which is what I have currently. Seat switch checks out for continuity though. Any thoughts? Model is 7fgcu20.

Thanks

Another detail to look at is the pedal return spring.
The return spring is a coiled spring that encloses the pivot of the pedal. The OEM springs were rather heavy wire and had only a few turns in the coil. These springs are fairly subject to breaking, which tends to make the pedal a little harder for the inching valve return spring to pull back.
Toyota had a running part change on the springs and the new springs are made of a slightly smaller wire, but have more turns around the pedal pivot.
I explain this so if you ever encounter a broken spring you will not think you are being sold the wrong spring, because it will look different than the old one.

Good point re clutch pack. Thanks again for your help.

I replace them when they fail to return.
My thoughts are that if it does not return, the wires that comprise the cable may be starting to unravel and fray.
If that is the case, lubing will not help.
You have already witnessed what happens when the inching valve does not close completely.
Now, would you really want to take a chance on burning up a clutch pack because it can't engage completely?

The inching cable seems to be the culprit, it looks new but sticks down when the pedal is pushed in then when you release the pedal the arm doesn't move back. Any idea if cable can be lubed or do you just replace it?

OK, concentrate on the inching cable diagnosis.
If you find nothing wrong there, you are going to need to check some electrical connectors for voltage at the appropriate directional switch positions.

Yes mast still worked fine.

" I was guessing on inching as the truck acted like the clutch was pushed in so to speak"

It does act that way, but it is a manually operated hydraulic valve inside the trans that dumps oil pressure from the clutch packs, not an electric switch.

A problem in the seat switch will affect Forward and Reverse alike, but if it is a seat switch issue, the hydraulic functions of the mast will also be inoperative. So, if you have not checked mast function when the trans does not engage, you want to do that to eliminate seat switch as a factor.

It has a seat switch and seems functional. Would not engage in reverse either. I will check as you've described thanks. I was guessing on inching as the truck acted like the clutch was pushed in so to speak. Also disclaimer was 0f outside when having this issue. Also seems like the idle is set high as it seems abrupt going into drive / reverse when it is working. Is there an rpm limit for tranny engagement?

And during all that time of no Forward, would it engage for Reverse?
There is not a switch for the inching operation, it is a manual valve that is cable operated by the left pedal.
It is not uncommon for a Toyota inching cable to become rusty, or even frayed, which can cause the cable to keep the inching valve enabled after the pedal itself returns to rest.
Take the floorboard out. With the engine not running, operate the left pedal hard and watch the movement of the inching cable bell crank arm in the top of the trans control valve. Familiarize yourself with which way it moves when the pedal is being pushed down. Now, with the pedal up........see if you can move the inching valve bell crank arm further towards its resting position. If you can move the arm any further by hand than where it stopped when releasing the left pedal, the inching cable is frayed or badly rusted.
Does this truck have a seat switch feature? Early 7Fs did not but late 7Fs do.