Need Help after Transmission Rebuild

[ltdaniel]

I just had the trans rebuilt after the shaft into the 3rd 4th gear planetary sheared all the teeth of the input shaft. New part including new production clutch plates throughout. The truck also has the Reb Shifter. I had drove the truck over 3000 miles before failure.

My problem is after putting oil (Dextron III) into the trans and getting the fluid coupling and the underdrive unit full of fluid It only shifts into reverse, it does not shift into drive.
I can't even feel it engage 1st gear.

I have gone thru the linkage adjustment per the manual, and I still can't feel it engage into drive.

Any ideas would help.

Thanks
Dan McCluskey

 

[NDT]

Line pressures in N D and R are?

 

[292FARMER]

have you verified splines on linkage were'nt worn and maybe its slipping and not actually turning splined end into valve body? was valve body cleaned after shaft broke? maybe a piece went into it. keep us posted

 

[ltdaniel]

The whole tranmission including the valve body were cleaned during the rebuild, the linkage is not worn and it is turning the splined end. I will check the pressures in all gears and get back to you.

 

[NDT]

I think reverse should be 220 psi and F1 etc should be 140. The fact that you have reverse means the pumps are working. If line pressure drops to nothing when engaging F1, pressure is escaping somewhere in the clutch packs or band servos.

 

[rustystud]

Sorry I didn't reply earlier. This transmission has several peculiarities including "recharging" the hydraulic lines after a complete rebuild. Make sure you have added the proper amount of fluid first, then let it sit running for at least an hour. Then go and shift through the gears. Slowly going into first and then reverse. Back and forth. Pretty soon you will start to feel the clutches starting to grab. Don't attempt to move it until you have strong engagement of the clutches. Usually this works.

 

[m1010plowboy]

I just had the trans rebuilt after the shaft into the 3rd 4th gear planetary sheared all the teeth of the input shaft. New part including new production clutch plates throughout. The truck also has the Reb Shifter. I had drove the truck over 3000 miles before failure.

My problem is after putting oil (Dextron III) into the trans and getting the fluid coupling and the underdrive unit full of fluid It only shifts into reverse, it does not shift into drive.
I can't even feel it engage 1st gear.

I have gone thru the linkage adjustment per the manual, and I still can't feel it engage into drive.

Any ideas would help.

Thanks
Dan McCluskey

Are we shifting yet?

You've shared some good news with the " New part including new production clutch plates throughout " statement.

If there are new parts available from a source you can reveal, it may help the rest of us out.

Are these new old stock parts, reconditioned or did Fatsco come through again?

Pass on some details if you can and we'll find a tall handsome secretary to put them on this list https://www.steelsoldiers.com/threads/g749-parts-list.137722/

If it's not shifting still and if Rusty doesn't already have a path to rolling again I know a fella that has a lot of success fixing these transmissions. Ol' GW from Reno excavating is a legend who seems to find more solutions then problems so keep us posted.

It could be as simple as air or........ after a brief lesson from GW...... the plungers in the control valve can get hung up and GW had a little trick where he'd bend a tab and everything would be okay. I wish I knew a way to bench test these because we've put 'clean' NOS control valves on old transmissions and had them work again. His fix had something to do with that swivel lever RR that wouldn't hold so had a trick. He'd also chain the trucks up and do some serious playing so he wasn't easy on his toys.




Let's hope it's simple and keep us posted.

 

[jeffhuey1n]

Following this thread. I’ve got one transmission that inop and another maybe inop. I’ve been reluctant to attack the repair because I’m clueless about automatic transmission repair.

 

[rustystud]

Are we shifting yet?

You've shared some good news with the " New part including new production clutch plates throughout " statement.

If there are new parts available from a source you can reveal, it may help the rest of us out.

Are these new old stock parts, reconditioned or did Fatsco come through again?

Pass on some details if you can and we'll find a tall handsome secretary to put them on this list https://www.steelsoldiers.com/threads/g749-parts-list.137722/

If it's not shifting still and if Rusty doesn't already have a path to rolling again I know a fella that has a lot of success fixing these transmissions. Ol' GW from Reno excavating is a legend who seems to find more solutions then problems so keep us posted.

It could be as simple as air or........ after a brief lesson from GW...... the plungers in the control valve can get hung up and GW had a little trick where he'd bend a tab and everything would be okay. I wish I knew a way to bench test these because we've put 'clean' NOS control valves on old transmissions and had them work again. His fix had something to do with that swivel lever RR that wouldn't hold so had a trick. He'd also chain the trucks up and do some serious playing so he wasn't easy on his toys.


View attachment 884491 View attachment 884492

Let's hope it's simple and keep us posted.

Hey M1010plowboy, how you doing ?
The problem with the old dual range hydro's wasn't so much the valve bodies since they are extremely simple but the many lines and servo's used in this transmission. The rear band servo holds almost a half a quart of fluid in itself ! Then there is the rear pump assembly which needs to purge itself too. So many places for the fluid to go to. Then there is the whole rear two speed section.
I've often thought I should come up with a "pressurizer" for this transmission, but since there is almost no need I won't try.
By the way. I'm almost finished with my new shop and I will be rebuilding my HydroMatic. I got a good one from Duuane in Canada last month, so hopefully it will have good parts in the rear two speed section.

 

[ltdaniel]

Success!!!!!!!!!!! It works, I had been only running it 15 -20 minuets at a time before, but when I let it idle for an hour, I was able to add 1 gal of oil then I could start to feel the clutches starting to grab. Let it run for another half hour then added another 2 qts, trans is working fine now.

As far as the replacement parts I will find out who they got them from but dont think it was Fatsco. He didnt have any problems getting any of the clutches or the replacement shaft.

The only part that I couldnt find was the 9" lip seal in the reduction unit, Memphis had the other 3 sizes but go figure my 9" lip seal had a small tear in it but it is working fine so far.

Thanks Again

Lt Dan

 

[m1010plowboy]

That's great news. It's a fun truck to drive. Pictures of that deuce with California behind it are always appreciated. It had to be the easiest solution in the G749 world of problems. "Let er' run and add fluid". Beautiful. Rusty's advice could breath new life into deuces people thought were dead. Thanks Rusty.

I'm almost certain I saw that seal in the hydromatic seal kits. We'll do some hunting. This could be the one.



The other unobtainium part that was hard to replace was the cone clutch. Did I hear that re-surfacing a clutch is an option? Enjoy that ride and once you get everything set up, give us a 0-50mph run.

 

[rustystud]

Glad to help.
Now about the cone clutch. Yes, they are as hard to find as "hens teeth" . I never saw anyone resurface one as you would also need to resurface the not only the aluminum cone but the housing as well. That would make your clearances a problem. The seal could be changed out to a "square cut" seal or better yet a "quad" seal 'O'-ring. Almost any " O-ring supplier " can make-up new O-rings at any size.
When my supplier went out of business, I almost bought the "do it yourself kit" but they wanted too much for it.
Soon I will have my new shop in order. Then I will start my rebuild of one of my "303M" transmissions.
I'll post pictures of course. Maybe I'll learn to post a video ! I'll ask my son to help with that. He'll be back for Christmas this year.

 

[lpcoating]

This thread is encouraging. My M221 has some transmission issues but I haven't had the time to work on truck since purchase. Plan is to start this winter and I'm sure I'll be needing some help from this forum.

Guy

 

[rustystud]

This thread is encouraging. My M221 has some transmission issues but I haven't had the time to work on truck since purchase. Plan is to start this winter and I'm sure I'll be needing some help from this forum.

Guy

My plan has been to try and post a complete picture by picture rebuild of the HydraMatic transmission. There aren't many transmission mechanics out there that have experience rebuilding them anymore. They kind of died out. I was lucky to have a mentor who actually worked at GM on the design and manufacture of this transmission. He died in 1980 though. I took copious note though, (if I can find them now) and rebuilt them under his tutelage. It never accurd to me that one day all the Dual range HydraMatic transmission mechanics would die out and all that knowledge would die with them. So before I check out I plan to leave at least a little bit of that old knowledge behind.

 

[DUUANE]

Glad to help.
Now about the cone clutch. Yes, they are as hard to find as "hens teeth" . I never saw anyone resurface one as you would also need to resurface the not only the aluminum cone but the housing as well. That would make your clearances a problem. The seal could be changed out to a "square cut" seal or better yet a "quad" seal 'O'-ring. Almost any " O-ring supplier " can make-up new O-rings at any size.
When my supplier went out of business, I almost bought the "do it yourself kit" but they wanted too much for it.
Soon I will have my new shop in order. Then I will start my rebuild of one of my "303M" transmissions.
I'll post pictures of course. Maybe I'll learn to post a video ! I'll ask my son to help with that. He'll be back for Christmas this year.

Happy holidays folks. And well.. If someone has a cone in good condition or can send me detailed drawings of what you need in a replacement cone..I have a very good friend with a cnc workstation who does custom one offs for my projects. Aluminum is a great material for custom because the feed rates are high(time) and its easy on the tooling. Once the toolpath files are generated he can push the go button whenever needed. A part for him to work from would be best.
One of our Canadian enthusiasts would probably be best suited to this, so we dont end up with 200+ questions sending used parts back and forth through the border. Ploughboy..might you have a spare for reverse engineering? If so give me a call. I'd be happy to help.

Is the part in question E (7411449) in the diagram above? A totally worn part would be usefull to send out for testing so we know what alloy they used, and if its a casting with post machining. There is a supplier here that has, and I'm not kidding, bar stock up to 6' in diameter in every alloy and forging known to man. Surprisingly not NASA expensive either. Best part is there is no minimum order. A slice of nice billet might stand up better than the OE part.

 

[lpcoating]

I'll also offer a reverse engineering option. We have a scanner at the shop that will draw a model file while it scans. I have no idea what this part looks like but I'll offer the service for the good of the hobby.

Guy

 

[rustystud]

Happy holidays folks. And well.. If someone has a cone in good condition or can send me detailed drawings of what you need in a replacement cone..I have a very good friend with a cnc workstation who does custom one offs for my projects. Aluminum is a great material for custom because the feed rates are high(time) and its easy on the tooling. Once the toolpath files are generated he can push the go button whenever needed. A part for him to work from would be best.
One of our Canadian enthusiasts would probably be best suited to this, so we dont end up with 200+ questions sending used parts back and forth through the border. Ploughboy..might you have a spare for reverse engineering? If so give me a call. I'd be happy to help.

Is the part in question E (7411449) in the diagram above? A totally worn part would be usefull to send out for testing so we know what alloy they used, and if its a casting with post machining. There is a supplier here that has, and I'm not kidding, bar stock up to 6' in diameter in every alloy and forging known to man. Surprisingly not NASA expensive either. Best part is there is no minimum order. A slice of nice billet might stand up better than the OE part.

Hey Duuane, I'll try and dig out one of mine and send it up to you. Maybe I'll just bring it up later.
I'll also bring up the housing it locks into so you can see how it works.

 

[DUUANE]

Hey Duuane, I'll try and dig out one of mine and send it up to you. Maybe I'll just bring it up later.
I'll also bring up the housing it locks into so you can see how it works.

Sure, sounds good. If lpcoating has access to a 3d scanner and conversion to .dwg or .dfx that would put it way ahead. Roy can definately give us an estimate based on that.
For my program i will need the transmission jack shaft we used to keep the environmental hazzard in Rusty's trans for the border fellows. It'll be mock up time here in a month or so for the new motor. *it's raining big blocks..lol*

 

[lpcoating]

Please post a picture of the part.

 

[rustystud]

Sure, sounds good. If lpcoating has access to a 3d scanner and conversion to .dwg or .dfx that would put it way ahead. Roy can definately give us an estimate based on that.
For my program i will need the transmission jack shaft we used to keep the environmental hazzard in Rusty's trans for the border fellows. It'll be mock up time here in a month or so for the new motor. *it's raining big blocks..lol*

Sorry about that DUUANE. Totally forgot about sending it back, what with the snow and ice storm lately. Plus Christmas and the kid coming home.
Maybe I will just drive up there and bring the jack-shaft and reverse cone with me. Save some money on shipping since it has gotten really crazy lately.