Case 580D shuttle shift problem after rebuild-HELP!

I have a 1982 Case 580D that I bought with a bad shuttle shift transmission. It had strong reverse, but no neutral or forward gears. I ordered a transmission rebuild kit and found the Case manual online and tore into it. Anyone that’s messed with these knows how the Belleville washers in the Fwd clutch assembly can break apart and wreak havoc. This was the case with mine. It destroyed the fwd clutch piston and cylinder. After I got everything back together, I had FWD/N/REV...but FWD was too weak to drive into a pile of dirt.
I decided to do a pressure test per the manual and these were the results:
0psi in FWD
0psi in Neutral
110psi in Rev at idle
140psi in Rev at full throttle
I removed the transmission and tore it back apart. I found the two small shaft seals on the FWD clutch that go into the planetary were torn. I replaced them and did a thorough inspection of the shuttle shift solenoid (again) and the entire fluid circuit that controls the fwd clutches to make sure I didn’t miss anything and I can’t find anything that I may have missed. I reinstalled the transmission and it still has 0 pressure in FWD. I’m at a loss and willing to listen to any advice.

Did you use the correct shim snap ring in the back of the clutch housing? You may need to check your fwd piston seal for a nick in it and the inner seal as well.

I measured the clearance and used the snap ring that gave me .023 (spec was .011-.046). I looked at the seals on the forward piston when I had it apart and everything looked fine. I even put compressed air to it to make sure it would move. I don’t understand why I have 0 pressure in neutral and great pressure in reverse

It’s been awhile since I pressure tested a shuttle but if I’m not mistaken you are only testing clutch pressure and neutral will be at 0psi.

Here I have attached a picture of my test results. (Guess I should’ve done that sooner)

Are you positive that the link at the transmission is going all the way into forward?

I unhooked the linkage and verified that it is going all the way forward. Even if the linkage wasn’t adjusted right, that wouldn’t explain me having zero pressure in Neutral

If I remember right the valve design was a pass through when in neutral so there would be no pressure. There should be a forward clutch pressure port for checking the forward clutch, and another pressure port for testing in reverse. Been quite a while since I rebuilt one of those but I have done many of them. If you get the stack heights right and don’t break any seals during assembly they are pretty bulletproof.

I also always make sure they lock both clutches with air pressure before I install them.

According to the Case manual there is one single test port on the top of the trans to test F/N/R clutch pressure and another port on the side to test trans cooling system pressures. According to the manual the port on the top should read minimum 60psi at idle no matter where the shifter position is F/N/R

...... we know what the manual says, but take a look at what this power shuttle says -
Regardless, you will need to pull it back out & retrace your steps - there's no other way to fix it.

Just curious, could there be a lip seal backwards or flipped? I have only been in a th350 and 400 years age.

mks said:

Just curious, could there be a lip seal backwards or flipped? I have only been in a th350 and 400 years age.

Click to expand...

This doesn’t have lip seals like a TH350, it has square cut seals

alrman said:

...... we know what the manual says, but take a look at what this power shuttle says -
Regardless, you will need to pull it back out & retrace your steps - there's no other way to fix it.

View attachment 228515

Click to expand...

Well that’s the first I’ve seen that. My transmission doesn’t have anything like that cast into it. It doesn’t have another port where the green circle is.
I HAVE retraced my steps, I’ve had it out and apart 3 times and I can’t find anything wrong. Trust me, the internet wasn’t the first place I turned when I had a problem with it. I realize I will have to pull it again, but it won’t do any good until I at least get a clue what I need to look for. I’m starting to think I have some wear that is letting fluid past a seal or O-ring.

Here is my transmission case

I don't recall ever seeing one of those without the forward/reverse test ports ever, marked or unmarked. They may be in different locations but they are there somewhere. It still sounds like something is missing, a snap ring?....An oring?...a seal ring?.....who knows? I know on these types of jobs you can get tunnel visioned and look right over the issue. Its happened to all of us............the best thing may be to remove it, tear it back down completely, and walk away from it for a day. I have done this and when I returned the issue slapped me in the face right off the bat. It can leave you feeling like a dumbass, but it gets the job done.

If your shuttle housing does not have the port shown in the image alrman posted how are the cooler lines connected ?
It is weird that your shuttle is different from the ones in the parts books and service manuals.

My transmission is just like the one in the manual. It is however different from the picture that was posted by Alrman that shows a casting depicting a separate test port location for forward and reverse. The cooler lines hook up on the right side of the transmission. The picture that was shared by both of us earlier showed the left side of the transmission.
Right there in the page for the manual you shared it shows the “Test port #1” as being on the top of the trans. Port #2 tests the trans cooling system

Not trying to argue, cause I am only looking at a screen, but is that some kind of bump, or casting mark, or what on yours right above where the green circle is on the clean one?

mitch504 said:

Not trying to argue, cause I am only looking at a screen, but is that some kind of bump, or casting mark, or what on yours right above where the green circle is on the clean one?

Click to expand...

I couldn’t tell from the pic either, so I went out and looked at the transmission. There is a port there. I’ve found a few things that on this trans that aren’t quite the same as the manual shows, I am willing to try just about anything at this point. I will hook up my pressure gauge to that port this afternoon and report my results.

Did you check the relief valve in the cooler line ?
It isn't stuck open from some kind of crap in it ?
It is still strange that you don't have that oil port on the upper rear of the case.
Here is an image from the service manual showing the oil flow.
Perhaps it may help.