8N transmission still locked up- What to do next?

The 2nd and 4th Gearshirt plate is still locked in the forward position and the 1st and 3rd Shift fork will not move. I jacked up the rear end and the wheels will turn in the opposite direction. But the tractor will not move with the clutch in. I bumped the starer and it will try to turn the transmission but it stops as the transmssion appears to be stuck.
I really need some help on what to do next. If I have to split the tractor do I take the the rear end off or do I also need to remove the front section where the engine mounts? I removed the front section when I rebuilt the clutch and engine and I do not want to go through it again.

Thanks,
Alex

It's looking like you are stuck between 2 gears.

Generally you have to have the rear jacked up, possibly get the rear wheels jiggles to and from with a friend helping, while you try to pry the other gear apart. The check out the shifting rails and detents.. You''l be lucky if you don't have gears with broken teeth at this point.

Soundguy