[Bill Hanlon]

Originally Posted by pontiacpark

yes Bill. feel changes to 3

Too bad. I was hoping you would have said you only felt one change instead of two.

The only kind of failure that would stall the engine at idle in 1-4 would be if both clutch and band were applied on either of the forward planetaries at the same time. That would effectively "lock up" the transmission. But reading through the theory of operation and eye-balling the schematics I can't figure out how that could happen with the selector in 1-4 and not happen with the selector in 1-3. There just isn't a single point of failure that should cause that symptom.

Of course it could happen with something like Steve said earlier like a crack in the throttle body allowing fluid to go from one point to another that it wouldn't normally go.

[Jack Gifford]

I don't disagree with Steve. But if it were mine, I'd still look first at the governor.

[stevep]

Originally Posted by pontiac jack

I don't disagree with Steve. But if it were mine, I'd still look first at the governor.

Jack,

I understand what you are saying, but how will the governor make the engine stall in 1/4?

The governor may be 1 part of the problem.

[Jack Gifford]

Originally Posted by stevep

... how will the governor make the engine stall in 1/4?...

I don't know. I just lean toward solving one issue at a time (blocked reverse).

Hmm... just thinkin' out loud... if the governor were stuck at the equivalent of, say, 50 MPH- would the valve body "think" it should shift to 4th? [I haven't looked at the control system diagrams to confirm this]

Nah... he says trans operates somewhat normally in D1-3 position...

[Bill Hanlon]

Originally Posted by pontiac jack

Hmm... just thinkin' out loud... if the governor were stuck at the equivalent of, say, 50 MPH- would the valve body "think" it should shift to 4th? [I haven't looked at the control system diagrams to confirm this]

Nah... he says trans operates somewhat normally in D1-3 position...

I think that is exactly what is happening Jack. Power flow in a dual-range Hydra-Matic in high gear passes through both planetaries in direct drive (clutches engaged, bands released) which according to the 57 GMC Hydra-Matic Transmission Operation and Maintenance Manual "Thus, the fluid coupling is relieved of engine power which results in a more efficient drive." If the governor was saying "50 MPH" when the truck was not moving having the selector in 1-4 would result in a transmission that emulated a stick shift in high gear with the clutch released.

Question for PontiacPark: If you get this beast underway in 1-3 up to 25 MPH and then shift it to 1-4 what happens? It'll either grenade the tranny, explode the rear end, bust the drive shaft or work normally. If you don't want to take the chance, I'd recommend checking the govenor as previously discussed.

[Bill Hanlon]

Originally Posted by Bill Hanlon

If you get this beast underway in 1-3 up to 25 MPH and then shift it to 1-4 what happens?

On second thought, what happens if you raise the rear axle a couple of inches off the ground with sturdy jackstands and try this experiment?

[pontiacpark]

hi guys. thanks for the help thus far. i have downloaded the manual thanks Bill, and i am going to put it on a hoist on the weekend. i have a freind who is a mechanic and although he has had no experiance with these we are going to look at the suggested areas you have provided to us and also look at what the manual says could be wrong. I will let you know how we get on with this. you guys have certainly given us a direction to look in. Bill i can put this in 1/4 after its been idling and it will go in but the truck starts to shudder and will stall. i have also put it in 1/4 while driving and it felt like the handbrake was on so i shifted it back out.

[stevep]

I do not believe that the governor is stuck. If it was stuck, you should not have on time 1-2 and 2-3 upshifts. High governor pressure would cause high gear starts.

You should see a 1-2 upshift @ approx 5-8 mph and a 2-3 @ approx 12-15 mph on a slight acceleration from a stop. If so, your gov pressure is fine.

I still think that you have a crack, mis-assembly or a cross leak.

[Bill Hanlon]

Steve has MUCH more experience with these transmissions than I do.

[pontiacpark]

Hay guys. just a question if you dont mind. truck is going down to my freinds shop tomorrow to go on the hoist to look at the valve body as suggested. i have been offered (for parts if required) a 4 speed auto trans out of a 1956 cadillac. are these the same transmission as mine.
thanks

[stevep]

No. A 1965 Caddy had a Dual Coupling Hydramatic. You have a Dual Range Hydramatic. You need a trans with a removeable side cover. A 1955 Caddy would work. Check that tag on the side of the case for the year.

[Bill Hanlon]

I have most of the original CA-55 transmission that I pulled from my truck 2 years ago. It still has the valve body intact. It "worked when I pulled it", although I'd recommend a good cleaning (and whatever Steve says) before putting it back into service. Transmission was changed at 190,000 miles because of poor performance which I attributed to the pounds of fragments I found in the pan. I'd let it go for $50.

Biggest problem would be getting it there. According to this
http://www.gcmap.com/mapui?P=DWH-WHK%0D%0A&MS=wls&DU=mi
a direct flight is 7329 miles and I don't think there are any direct flights.

[stevep]

Originally Posted by Bill Hanlon

I have most of the original CA-55 transmission that I pulled from my truck 2 years ago. It still has the valve body intact. It "worked when I pulled it", although I'd recommend a good cleaning (and whatever Steve says) before putting it back into service. Transmission was changed at 190,000 miles because of poor performance which I attributed to the pounds of fragments I found in the pan. I'd let it go for $50.

Biggest problem would be getting it there. According to this
http://www.gcmap.com/mapui?P=DWH-WHK%0D%0A&MS=wls&DU=mi
a direct flight is 7329 miles and I don't think there are any direct flights.

You should grab that valve body!! I have shipped to Au before without an issue.

[pontiacpark]

hi guys. thanks for the help thus far. Bill i will buy that thanks. can we get details and i will have my friend in portland send you the funds including your shipping costs.. you can then sent the part to him to foward to me. guys, we have had the valve body out. there was a stuck valve. there are no apparent cracks in it. we cleaned it all and put it back together but still wont go into reverse.
there was 3/8" of gunk in the bottom of the pan. my mechinac has checked the govener and a number of other things as recommended by both you guys and from the manual. can you contact me bill with details so i can get payment to you.

[Bill Hanlon]

PM sent.

[pontiacpark]

thanks bill. my friend is fowarding payment to you. Could pressure be a cause for my problems with this auto. we have checked tolerances as stated in the book, freed up stuck valve in body but still no luck.

[Bill Hanlon]

Payment received. Valve body packed and I will drop it at the post office on the way home tonight.

As long as you have the valve body off, I would recommend doing the "air check" on as many of the test points as can be reached without removing more pieces from the transmission. I have documentation on this test that I'll try to get posted somewhere in the next few days.

Steve:
While I was removing the valve body last night I decided to pull the governor/rear pump while I was at it. I was surprised to find the the weights (G1 and G2) are not spring loaded. What keeps them "analog" instead of "digital"? That is, what makes them come out further at higher speed than at lower speeds?

[Bill Hanlon]

"It's in the mail".

Delivery scheduled Monday in Vancouver.

[stevep]

Originally Posted by Bill Hanlon

Payment received. Valve body packed and I will drop it at the post office on the way home tonight.

As long as you have the valve body off, I would recommend doing the "air check" on as many of the test points as can be reached without removing more pieces from the transmission. I have documentation on this test that I'll try to get posted somewhere in the next few days.

Steve:
While I was removing the valve body last night I decided to pull the governor/rear pump while I was at it. I was surprised to find the the weights (G1 and G2) are not spring loaded. What keeps them "analog" instead of "digital"? That is, what makes them come out further at higher speed than at lower speeds?

Bill,

I never thought about it that way. Other governors are also not spring loaded, some have 1 spring and others have 2.

I totally agree with performing the air checks while the VB is off.

[pontiacpark]

Hey guys, Thank you for your excellent feedback, help, parts and excellent advice. The truck is running as of today. My mechanic did a number of air tests,checking of wear against recommended tolerances etc. sorry, i dont know the whole of everything he did but no parts were purchased except for a bottom pan gasket. I know he repaired a stuck valve, (truck still didnt go in reverse) then he "longboarded" with 2400 sandpaper all the mating surfaces on the valve body. He was thinking that steve was right and there may have been a crossleak through a poorly aligned surface. He measured the tolerances and they were all within the ranges specified in the repair manual. He summised that there may have been a couple of little things that added together to give the transmission problems?. This transmission is certainly going to need a rebuild soon. Can you recommend anyone in America that is experianced with these transmissions. Maybe someone has a core i could purchase. Now i have some breathing space i can rebuild a correct transmission. I thank you all for your help.great advice