I had my sunroof (aka sliding roof) out of the car, and even though it worked OK at 25yrs I decided to service it. Maybe this will add some missing details to the existing posts on the subject.

The FSM has some good illustrations, but their names are not mine. I show this as myname (aka toyotaname).

Removal
The headliner can slide back and out without removing the larger trim pieces. Just slide down the front seat belt mounts and unclip any trim at the very top where it overlaps the headliner. Shims can be placed to force the trim down and away so the headliner is free. Remove sunshades, rearview, dome lights, etc. The screws on the grab handles will be much easier to remove after applying some heat from a soldering iron to soften the locktite. Without heat, an impact driver may just strip the screw heads.

The black H-frame (aka sliding roof rail) is held on by 8 hex bolts and 2 nuts, a push nut, and misc hoses and wire connectors. I used two ropes looped over the roof to raise and lower the H-frame, making this a one person job. I left the heavy glass attached to preserve alignment, but this was not necessary. I loosened all the fasteners and used a sturdy pick/probe to pry at the fingers of the push nut until it released. The whole thing can then be lowered and removed.















Disassembly
After removing the drive motor, roof glass and unsnapping the rear drip channel, I tried pulling the left slide (aka drive rail) backwards but it was in the forward position which mechanically locks it to the rail via a white tab and notch. The only way to unlock it is for the cable to push backwards, so I used a screwdriver to push on the cable coils via the gearbox, forcing it an inch back into the tube and unlocking the slide. I was then able to pull the slide back and out of the H-frame, but there was a lot of drag. The same trick didn't work for the right slide since it was too bound up, so I had to disassemble the entire thing anyway. Penetrating oil was of limited help on this. In hindsight, powering the sunroof back a few inches before removing it from the car would at least unlock both slides removing that obstacle. Even if slides operate fine in their normal range, once they move back past that 'comfort zone', built up crud and degraded cables may cause severe binding.

Each drive cable consists of a steel core wrapped with a spring coil. The coils serve as gear racks that engage the motor pinion at the gearbox. Each cable is further encapsulated in a plastic sheath (it isn't hardened grease). This plastic is durable but breaks down after 20 years or so. The plastic on my cables looked good at both ends but had degraded or missing sections where the motor pinion chewed on it. These ragged sections could be the main source of binding since there isn't much clearance in the cable tubes and H-frame bores. I removed most of the plastic on each cable leaving only a few inches at the loose end of the cable which still looked good. My method was to manually pick at it with an exacto knife and also use a wirewheel on a bench grinder. In some sections the plastic could be unwound in a long piece, in others it needed the wirewheel before the plastic could be picked or peeled away. I spent up to an hour cleaning each cable.

Assembly
Exploded view of left sunroof cable slide (aka drive rail). From Rt to Lt: guide shell, roller ring, cable & carriage assy, round plastic cap/bushing, slide frame, 2 screws.
I used vice grips with sharp teeth to loosen & tighten those screws rather than risk stripping the heads.



Left slide assy all greased up. Make sure the white plastic tab on the metal spring arm ends up on top (not below) the long black cable carriage arm like so.
Both cable slide assys. The white tabs are shown correctly positioned.





I made sure to run the cables in and out of each guide tube to make sure they were free of binding.
Assemble & position the guide tubes (aka casing pipes) onto the H-frame (no screws yet). Attach the white tube support clips with 2 screws. If the gearbox clamp has been removed, make sure it is fairly level before tightening the 2 clamp screws.



Wiggle the large drip tray into position without dislodging the guide tubes (no screws yet).



Attach the two front carriage stops (aka casing pipe stoppers) with 4 screws. These hold the H-frame to the drip tray.
Add the six pan head screws for the drip tray.



Attach the front wind deflector with 2 screws.



Test the fit of the cable & slide assys (aka drive rails) in the frame without any grease. They should slide without much force.
Grease all guide grooves and cable channels. Grease each cable as you feed it into the H-frame. Rather than white lithium grease I used a marine type thinking that water is the main issue. It had a strong smell at first but that went away.
Snap on the rear drip channel.



Adjust and sync the motor to the sunroof:
My sunroof was aligned and working before, and I took care to remount the glass exactly as it had been so I expected that I would just need to align the motor. The alignment advice in the FSM seems incomplete. Even if I aligned the motor to the motor index mark, the sunroof first needs to be in the closed position and you can't easily push it there. The motor needs to drive the cable to get it there. Catch-22.

Initial alignment
Once the H-frame is fully assembled (but no motor), pull the sunroof slightly back to make sure it is in the lowered 'sliding' position then bolt the assy back into the car. Push the sunroof all the way open against the rear stops. Power the disconnected motor to to the fully open position before mounting it to the gearbox. This will provide a safe starting point for the actual alignment. The sunroof can be powered thru its entire range using just the slide button, but it won't stop automatically in the fully closed position like it should.

Final alignment
You have to power the sunroof forward until it just bumps up to the flush closed position, and THEN remove the motor. If the motor is working as it should, there is no reason to worry about the index marks unless you are curious. Just use the slide button to drive the disconnected motor all the way 'back' until it stops whirring, then drive it forward until it stops once, then again forward until it stops a second time. The motor is now in the closed position, and you can remount it. If you are looking at them, the index marks will be aligned. The slide and tilt buttons should now work normally to position the sunroof. I found that my sunroof sat a bit low in the closed position so I later added 4 washers at the glass mounts to bring it flush.