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Nature: "Transmission shifts satisfactorily through 2nd and 3rd speeds (Dr range), but will not shift into 4th speed (Dr range)." Cause: " Sticking 3-4 shifter valve and/or governor valves." Correction: "Completely disassemble and inspect valve body and governor assemblies".
Sounds like you spent a lot of time of the 3-4 shifter valve. Have you completely disassembled the governor assembly and inspected cleaned it?
Nature: "Transmission shifts satisfactorily through 2nd and 3rd speeds (Dr range), but will not shift into 4th speed (Dr range)." Cause: " Sticking 3-4 shifter valve and/or governor valves." Correction: "Completely disassemble and inspect valve body and governor assemblies".
Sounds like you spent a lot of time of the 3-4 shifter valve. Have you completely disassembled the governor assembly and inspected cleaned it?
I get that part, but it says governor assembly’s like plural, is there more than one? The only one I’ve seen is the one that sticks out where the side pan goes. That’s where I’m lost
I get that part, but it says governor assembly’s like plural, is there more than one? The only one I’ve seen is the one that sticks out where the side pan goes. That’s where I’m lost
and no I have not removed the governor because it sounds like there’s 2 and I’m not sure which one to remove
and no I have not removed the governor because it sounds like there’s 2 and I’m not sure which one to remove
There are at least two, but they're both in the same valve body.
See the illustration below.
The thing about these spool valves, is that they fit in their bores to very close tolerances.
At least ten thousands of an inch and maybe up to 100 thousandth tolerance.
Debris so small you can't see it can still cause problems.
check the paragraph below.
Quote; " It can be assumed that the valves and plugs are free in their operating positions.
If they will fall of their own weight in their respective bores when the valve body is shaken slightly."
There are at least two, but they're both in the same valve body.
See the illustration below.
The thing about these spool valves, is that they fit in their bores to very close tolerances.
At least ten thousands of an inch and maybe up to 100 thousandth tolerance.
Debris so small you can't see it can still cause problems.
check the paragraph below.
Quote; " It can be assumed that the valves and plugs are free in their operating positions.
If they will fall of their own weight in their respective bores when the valve body is shaken slightly."
when I cleaned the valve body I made sure all pieces were cleaned and slid back in there place with no restrictions. What about this governor that’s behind the parking bracket? Is that messing up my 4th gear? Do I need to clean it? And that rear servo I think it’s attached to the case and the bands.
when I cleaned the valve body I made sure all pieces were cleaned and slid back in there place with no restrictions. What about this governor that’s behind the parking bracket? Is that messing up my 4th gear? Do I need to clean it? And that rear servo I think it’s attached to the case and the bands.
Look at the previous illustration.
Note that parts #27, 41 & 42 comprise the 3 to 4 shift valve.
Th entire valve assembly has to come out to be cleaned.
As others have mentioned, ultrasonic cleaning is best.
Look at the previous illustration.
Note that parts #27, 41 & 42 comprise the 3 to 4 shift valve.
Th entire valve assembly has to come out to be cleaned.
As others have mentioned, ultrasonic cleaning is best.
I cleaned all those parts. I’ll do it again I guess, but there has to be another part of the trans that also controls this 3-4 shift and if I’m opening it to clean the valve body again might as well do what else controls that shift I just need to know what exactly. Governor behind parking bracket or the servos front and or rear?
I cleaned all those parts. I’ll do it again I guess, but there has to be another part of the trans that also controls this 3-4 shift and if I’m opening it to clean the valve body again might as well do what else controls that shift I just need to know what exactly. Governor behind parking bracket or the servos front and or rear?
remember that little o ring I showed you that fell out? Which by one on that illustration is that?
Look at the previous illustration.
Note that parts #27, 41 & 42 comprise the 3 to 4 shift valve.
Th entire valve assembly has to come out to be cleaned.
As others have mentioned, ultrasonic cleaning is best.
is the 3-4 shifter valve the one that has a pin holding part of it into the valve body? I want to make sure I clean whatever needs to be cleaned because last time sucked and I’m not looking forward to doing it again
im just trying figure out how it came off when the pan came off? It must go on the outside of that shifter selector. But does it go over that little pin or under it. Just doesn’t make sense how it could fall off when I took the side pan off. If anyone else has an idea of what other part I must take off and clean next time I try this operation, please jump in. And I even been watching the videos of the hydramatic rebuild on YouTube which I think that guy has commented on this post his username looks familiar. But I didn’t hear him say a lot of explanation on what each parts do.
I cleaned all those parts. I’ll do it again I guess, but there has to be another part of the trans that also controls this 3-4 shift and if I’m opening it to clean the valve body again might as well do what else controls that shift I just need to know what exactly. Governor behind parking bracket or the servos front and or rear?
The early Hydra-Matics were hydromechanically controlled.
A basic knowledge of hydraulics is helpful.
The front and rear servos apply the bands. The fact that you're getting 3 gears rules them out as a problem.
Yes, the " governor behind the parking bracket " is another valve body and should be entirely disassembled and cleaned thoroughly.
"Decisions " on when to change gears are driven by the pressure on certain valves. The pressure is created by the front and rear pumps.
It is modulated by the TV control and the gear selector (NDSLR)
Make sure all those governor valves slide freely, especially the 3 to 4 valve , # 41 on the illustration.
Last edited by Charlie Jones; February 26th, 2024 at 09:14 AM.
The early Hydra-Matics were hydromechanically controlled.
A basic knowledge of hydraulics is helpful.
The front and rear servos apply the bands. The fact that you're getting 3 gears rules them out as a problem.
Yes, the " governor behind the parking bracket " is another valve body and should be entirely disassembled and cleaned thoroughly.
"Decisions " on when to change gears are driven by the pressure on certain valves. The pressure is created by the front and rear pumps.
It is modulated by the TV control and the gear selector (NDSLR)
Make sure all those governor valves slide freely, especially the 3 to 4 valve , # 41 on the illustration.
ok this helpful! It’s hard for me to understand things but when you dumb it down for me it helps me understand it then gives me a better chance of doing what needs to be done. Ok so I’ve done the 30mph test shut the engine off put it back in drive and the engine started up so I was told that means my pumps are good. Ok so to break it down, I will again disassemble the valve body and clean it as well as that governor behind the parking bracket. For that governor, am I just taking off what I can get to since the trans is still in the car? I know there’s two front bolts and there’s the shaft that has metal rings around it kind of like rings on the pistons in the engine. But does that come out too?
The attached diagrams might help clarify what is going on between 3rd speed and 4th speed. Basically, the rear unit doesn't change state (clutch is on in 3rd and stays on in 4th). The front unit changes by applying the clutch and taking the band off, so both clutches are applied and both bands are off.
From the diagrams, the things that can stop the front unit from going from band on/clutch off, to band off/clutch on are:
The early Hydra-Matics were hydromechanically controlled.
A basic knowledge of hydraulics is helpful.
The front and rear servos apply the bands. The fact that you're getting 3 gears rules them out as a problem.
Yes, the " governor behind the parking bracket " is another valve body and should be entirely disassembled and cleaned thoroughly.
"Decisions " on when to change gears are driven by the pressure on certain valves. The pressure is created by the front and rear pumps.
It is modulated by the TV control and the gear selector (NDSLR)
Make sure all those governor valves slide freely, especially the 3 to 4 valve , # 41 on the illustration.
just to confirm, I’m removing this governor correct?
And do I need any special tools to install it back in?
The attached diagrams might help clarify what is going on between 3rd speed and 4th speed. Basically, the rear unit doesn't change state (clutch is on in 3rd and stays on in 4th). The front unit changes by applying the clutch and taking the band off, so both clutches are applied and both bands are off.
From the diagrams, the things that can stop the front unit from going from band on/clutch off, to band off/clutch on are:
Hey guys so my super 88 55 automatic I let sit for 6 weeks after cleaning the valve body and still no 4th gear, but yesterday I finally drove it and it tried to go into 4th gear. Any ideas?
The most likely candidate to resolve your issue is going to be a new transmission since it's likely the rear transmission band has broken. Simply pointing out the basic truth straight-away up front.
NOTE: In the URL link I sent to you what Glenn (redoldsman) states:
If you can find a 55 transmission fine, if you can find a 54 transmission even better.
I thought if it was going into third then it wasn’t the rear band? Again just cleaned and inspected the whole valve body and let it cook in one of those high temp cleaners and put it back together using atf on each part and still no 4th gear so idk now
Chris,
When you get brave enough to tackle tearing down the valve, I would suggest you invest in an Ultra Sonic Cleaner. You can get a small one at Harbor Freight for about $90. It's the only way to go when you want to get small parts clean. All you need is warm water and a shot glass of Simple Green. The parts will come out looking like new. Just make sure you take lots of pictures as you take the valve apart. The diagrams in the manual are very detailed but you need to make sure you identify each spring and each valve spool as you take the valve apart.
I've done a couple valves so if you need help just let me know.
Wally
so I’ve cleaned the valve body a second time with ultrasonicccleaner. Can someone explain what goes on in the trans when it goes from 3 to 4th gear?? It can’t all be only valve body. Is part of it the rear band? Rear servo? Governor where parking pawl is? I’m wondering if my rear band needs adjusted?
Chris - Post #94 specifically states what happens with the transmission when the shift is from 3rd to 4th gear. I've include the .pdf file as an attachment.
Chris - Post #94 specifically states what happens with the transmission when the shift is from 3rd to 4th gear. I've include the .pdf file as an attachment.
so it could be the front band not releasing or could be the pressure regulator? Cuz my VB is spotless as should be. I know it’s all been stated before I’m just having a hard time understand it.
The attached diagrams might help clarify what is going on between 3rd speed and 4th speed. Basically, the rear unit doesn't change state (clutch is on in 3rd and stays on in 4th). The front unit changes by applying the clutch and taking the band off, so both clutches are applied and both bands are off.
From the diagrams, the things that can stop the front unit from going from band on/clutch off, to band off/clutch on are:
February 25th, 2024, 03:34 PM
