[Bill Hanlon]

Attached is the diagnostic test listed for the "Misses 1st, 3rd and reverse" problem. Luckily, this example happened to use a 1955 Pontiac!

[Bill Hanlon]

Originally Posted by Onestone

Reverse is working without any problems. So in total whats good:
- 2nd, 4th, R and N are working fine
- upshift from 2nd to 4th happens (I think it happens where the 2nd to 3rd upshift should be)

Given the troubleshooting test I posted, in the condition of "locked up front planetary", the locked up planetary would overcome the applied band, making the band slip. This would allow reverse to work, but at a higher ratio than normal.

By the way, driving the car in this condition put additional wear on the front band.

[Bill Hanlon]

I still don't understand what would cause the planetary in the front unit to "lock up". Lack of fluid pressure and it's internal springs SHOULD cause it to disengage in 1st or 3rd gear. I guess it could be getting constant fluid pressure of some kind or a mechanical failure inside the the front unit has jammed it engaged.

Jack probably has more insight.

[Jack Gifford]

Rear band not doing its job? Broken band or servo...?
But of course, valve body problems can create any sort of symptoms.

[Onestone]

So what would you guys suggest doing next with my transmission? Open it and check for a broken band?

[Bill Hanlon]

The problem isn't with the bands (yet).

The front unit clutches are always engaged or it is physically locked up due to some kind of internal failure.

When the transmission is in 1st, 3rd or reverse the front unit clutches should be disengaged and the front unit band should be applied, causing engine power to flow through the front unit planetary and provide a reduction gear ratio. With your failure, the front unit is trying to provide both reduction because the band is applied as it should be and direct drive because the front unit is "locked up" as it should not be. Something has to "give".

In your case the amount of torque supplied by the engine through the "locked up" front unit is strong enough to overcome the band's grip on the front unit in 1st, 3rd or reverse gears. In 2nd and 4th gear the front unit is supposed to be "locked up" with the band released, so these gears work as they are supposed to.

I'll bet reverse on your car is operating at a much faster speed (because the front unit is locked up) than it should be. But if it is operating at normal speed that would mean that the front unit clutches and springs are operating as they are supposed (disengaged) and would point to problems in the control unit of the transmission. Pray for this as it wouldn't require a complete tear down of the transmission.

There are "air check" tests in the GMC HydraMatic Maintenance Manual that involve removing the side cover and the control unit under the cover. Then using compressed air through ports to activate various functions (such as front unit clutch engage) in the transmission and listening for the transmission to react. These could probably be done with the transmission mounted in Jack's "ladder frame" GMC pickup truck, but doing them on an "X frame" '55 Pontiac would most likely require removing the transmission to have enough room to get the side cover and control unit off.

Me? I'm saying 3:1 odds that the problem is inside the front unit. That would be verified by listening to the "thunk" when the front clutches are applied and released and comparing those sounds to apply/release sounds in the rear unit.

Back to the "yet" in the first line of this post. Because the front unit band is (and SHOULD BE) applied during 1st, 3rd and reverse gear and the front unit clutch is (and SHOULD NOT BE) applied the bands are slipping and subject to more than normal wear during 1st, 3rd and reverse.

[Onestone]

Thank you for your efforts helping me @ Bill and Jack!

Bill, I think you are right regarding the reverse gear too. The reverse gear seems to have the same speed as the lower forward (2nd) gear. I always have to drive with two feet, reversing without braking a little at the same time isn't possible.

I am thinking about my options now...:

• Throttle lever and linkage adjustment: I haven't done this yet. What you have been writing so far, this seems not to have chance to solve my trans problems, right? Still worth a try? I have read the procedure in the OnCar Hydra manual, this is something I could do myself: https://www.pontiacsafari.com/L1Gara...ic_1946-55.pdf
  
• Remove the transmision and do the air pressure checks: This is maybe even possible without removing the trans, see the picture. I read the section in the Hydramatic manual (https://forums.maxperformanceinc.com...8&d=1775322478, Page 117 and on). Whatever will be the result, locked front planetary for example, it will lead to something that would require a transmission overhaul. This is something I can not do myself, since I dont have any of the tools and gauges described in the manual. I have done several engine overhauls, but never done any transmission overhaul, so I don't have any experience here.
  
• Remove the transmission and give it to a company for fix and overhaul: possible, but really difficult here in Germany. I already searched and phoned with companies who could do that, I found just two in the whole country so far. Many do overhauls for TH transmissions, but when they hear "Hydramatic 1955" they instantly refuse. Those two doing ask for around 4-5000 EUR for an overhaul (!!!). So this would be super f'ckn expensive
  
• Look for an already rebuilt transmission: impossible to find here, but even buying one in the US and importing it can be less costly than a local overhaul here. Any hints where I could take a look for this option? Sometimes there are some on ebay, like this one: https://www.ebay.com/itm/188266362636, but never rebuilt
  
• Swapping to a more modern TH trans: Seriously an option because of reasonable prices of overhauled TH transmissions here - if technically possible at all. What I have read so far, no TH trans bolts to my 287 engine because no BOPC pattern. The one and only solution I found is this trans adapter: Wilcap WPO101. Anyone used this one and can say something about it? I guess the propeller shaft be the next problem then (?), will it fit to lets say a TH200R4 or similar?

Generally I would like to stay at the original Dual Range Hydramatic... Any hints or experiences which could help to make a good decision here...?

[Bill Hanlon]

Originally Posted by Onestone

Throttle lever and linkage adjustment: I haven't done this yet. What you have been writing so far, this seems not to have chance to solve my trans problems, right? Still worth a try? I have read the procedure in the OnCar Hydra manual, this is something I could do myself:

I don't think it would solve your problem. I'd wait until after you have solved the locked-up front unit problem.

Remove the transmision and do the air pressure checks: This is maybe even possible without removing the trans, see the picture. I read the section in the Hydramatic manual (https://forums.maxperformanceinc.com...8&d=1775322478, Page 117 and on). Whatever will be the result, locked front planetary for example, it will lead to something that would require a transmission overhaul. This is something I can not do myself, since I dont have any of the tools and gauges described in the manual. I have done several engine overhauls, but never done any transmission overhaul, so I don't have any experience here.

If you can get the side cover off while the transmission is still in the car I think this would be worth a try. Reason: Because air checks should be able to tell if the problem is the front unit is locked up mechanically or is being told to lock up all the time by the control valve unit.

Jack: Any chance this could be a "stuck" governor problem?????

[*]Remove the transmission and give it to a company for fix and overhaul: possible, but really difficult here in Germany. I already searched and phoned with companies who could do that, I found just two in the whole country so far. Many do overhauls for TH transmissions, but when they hear "Hydramatic 1955" they instantly refuse. Those two doing ask for around 4-5000 EUR for an overhaul (!!!). So this would be super f'ckn expensive

Ain't cheap! Just for fun, contact your local Rolls Royce club and ask who they go to for 1966 and earlier automatic trans work. RR licensed the Dual Range HydraMatic from GM.

Look for an already rebuilt transmission: impossible to find here, but even buying one in the US and importing it can be less costly than a local overhaul here. Any hints where I could take a look for this option? Sometimes there are some on ebay, like this one: https://www.ebay.com/itm/188266362636, but never rebuilt

I'd talk with these HydraMatic parts suppliers because they may have customers in Euro land.

http://www.fatsco.com/
David Edwards at http://www.autotran.us/
http://nwtparts.com/.

I'd also ask our fellow forum guy SteveP who owns a shop that overhauls "antique" automatic transmissions.

[*]Swapping to a more modern TH trans: Seriously an option because of reasonable prices of overhauled TH transmissions here - if technically possible at all. What I have read so far, no TH trans bolts to my 287 engine because no BOPC pattern. The one and only solution I found is this trans adapter: Wilcap WPO101. Anyone used this one and can say something about it? I guess the propeller shaft be the next problem then (?), will it fit to lets say a TH200R4 or similar?

Probably need driveshaft work, but that typically isn't real expensive. Also consider there are special U joints to help connect one type trans to another type driveshaft.

Generally I would like to stay at the original Dual Range Hydramatic... Any hints or experiences which could help to make a good decision here...?

I would too, but this is your decision to make.

[Jack Gifford]

Originally Posted by Bill Hanlon

... Jack: Any chance this could be a "stuck" governor problem?????...

I don't think so. To be missing 1st & 3rd the governor would need to be stuck in "high speed" position. But he is able to shift into reverse, which can't be done if the governor thinks you're going over 8 MPH.
Onestone: I've been conversing with a guy in Denmark who has a number of Pontiacs, including a '57. I'll ask if he would allow me to give you his email address. Perhaps he would know of some European sources for help with fixing or purchasing HydraMatic stuff.

[Onestone]

Bill & Jack, thank you again! So I will try to get my Hydramatic transmission repaired and overhauled.

@Jack: That wold be great! I also just sent you a PM with my contact data for this.

[Bill Hanlon]

I'd love to know what was found wrong when the repair/overhaul is done.

[Onestone]

Originally Posted by Bill Hanlon

I'd love to know what was found wrong when the repair/overhaul is done.

Good news, I finally found a workshop who will do the rebuild of my '55 Hydramatic transmission. I have to remove the transmission by myself and bring it to them. I have been warned it will be heavy They have experience with the classic Hydramatics and also recommended a better (external) cooler for the transmission fluid after the rebuild is done.
They will open the trans with me together and check for the main problem, I will report it here @Bill

Bad side of the news: they don't have time for this before mid of May, and told me the rebuild will most likely take 1-2 months because of very long delivery times for parts, main reason are the current customs policies .
They know the rebuild kits from Fatsco, and said some parts of those kits are of bad quality and its better to use NOS parts if available, and some parts like bearing shells they even make themselves. And it will be expensive (of course )

So that's the plan now - any hints how to remove the transmission are welcome of course, since it's my first Pontiac. I already read the trans removal section in the shop manual tho...

[Bill Hanlon]

I know some of the GMC truck Hydra-Matic transmissions had external coolers (optional on smaller trucks, standard on larger trucks), but I've never heard of one being available on a car. On the trucks with coolers the connections for the fluid to enter and exit the transmission go through the side of the bottom pan and the pan is much deeper than the non-cooler pan. Your '55 Pontiac "slant pan" transmission would not lend itself to additional plumbing.

The torus in these transmissions do not generate as much heat as the torque converters in newer transmissions. I'd ask Jack Gifford his opinion of the need for a cooler. His GMC truck is equipped with the lightest (177C or 177CA, I can't remember which) HydraMatic being pushed by a MUCH more robust Pontiac V8 than yours. Jack is known for over-engineering almost everything. https://www.facebook.com/groups/3864...4559186330594/ If he says put in the cooler, then I'd ask the transmission shop how they plan to attach the plumbing to the HydraMatic.

[Jack Gifford]

I'm glad you found a shop to do the Hydro.
Fatsco has been a godsend for me to obtain hard parts- shafts, gears, etc. - sometimes used but good. "Rebuild" parts- gaskets, seals, etc. are generally also available other places.
You don't need a cooler. I've used dual-range hydro's in all sorts of things. This included a HydroStick in a Tri-Power 4,200 pound car that ran two hard laps of Nuerburgring- that's a total of 34 miles- turning 6,500 rpm on straight stretches. The hydro was in fine shape... but I wasn't. The "ring" has about 170 turns and I had to manhandle that 4,200 pounds with manual steering, but with the pitman arm and idler arm changed to power steering pieces to quicken the ratio!

[Onestone]

Ok, so I will ask them regarding the cooler again. Maybe they had the truck Hydramatic in mind.

@Jack: Wow, I saw that FB posting, now THAT is impressive !!!

Meanwhile some other side tasks happened here and are ongoing, stagnation is not an option!

***image flood warning***

This is how my dashboard looked when I bought this poncho:



Some time later I realized that the radio is beautiful, but not the original one. I think it's from a 70s Corvette or similar. The bezel was also badly cut out if you look closer. The clock was also not the original one, its a 6 Volts VDO clock from a Volkswagen or Ford I guess (not connected ofc). Both is for sale if anyone needs

I was lucky to get the original radio and an undamaged bezel from an ebay seller from Ohio. The radio doesn't work of course, but that doesn't matter because it just receives medium wave radio and there are almost no more radio stations receivable here in Europe. I also have a small modern Bluetooth radio in the glove box anyway

Interesting how the 50s valve radios look inside:


So I just cleaned and polished it and repaired the backlight and swapped it in. Just the knobs were the wrong ones, so I made 3D-Print replicas, filled and painted them - if anyone wants the models just drop me a message. If anyone has two original radio knobs to sell I would be happy for a message too

This the new beauty:



The original clock was much harder to find. I didn't found a single one on ebay over many months. After a while I found https://mainstreetclassiccarclocks.com/ and asked them for help. They actually had one in very good optical condition, but with a broken coil and had no replacement part.
Very nice and friendly owner btw!
I bought it anyway, and did a quartz conversion myself because I wanted to have a working clock. The quartz clockwork was originally for a 1,5V battery, so I had to add a voltage converter on the backside:



Complete new original look:


Next thing that was a must have for me was the illuminated hood ornament. Don't ask for the price I paid at the end including shipping, taxes and customs, completely unreasonable But I needed this And fixing the lighting was the first thing I did ofc



I also got a complete new amber insert meanwhile, not mounted yet. Pics from a small ride a few weeks ago:



Last side task was the original washer glass. I got a rusty lid with a vacuum pump for rebuild, and bought an electrical replacement pump and a replica of the original decal:



I sanded, filled and painted the lid, and had to 3d print an adapter for the thread of the new glass:


Mounted the new pump, added the decal, and made too many pictures :



Working as expected

More to come soon.

[Jack Gifford]

Nice work!

[Scarebird]

Originally Posted by Onestone

...Some time later I realized that the radio is beautiful, but not the original one. I think it's from a 70s Corvette or similar... Both is for sale if anyone needs...

I sent a message a bit back as I may be interested in the radio.

[Pigeon]

Your car is beautiful! What a piece of art. The two tone colors complement each other so well. The dashboard looks like something from a Buck Rodger’s movie! Not many people will know who that is. Congrats

[Onestone]

Thank you guys for the nice comments

Since I shortly will remove my transmission and give it away for repair, I am currently thinking what to do with my engine meanwhile. Once the transmission is out, I plan to take out the engine too so I can access it from all sides.

The engine is running fine, so no major problems. It's leaking oil on many places, and also needs a new painting, since the preowner sprayed it red Other than that I am not sure about how good the compression is:

I measured around 110 psi at cranking speed on all eight cylinders (warm engine, throttle fully open). I have the 287 engine with 2 barrel Carter carburetor, but I'm not sure if I have the version with 7,4:1 or 8:1 compression ratio.

The shop manual says it should be 135-145 psi compression, but I think this is the value for a new engine (?). So is this a good compression, or not...?


The absolute minimum I want to do is:
- clean it
- replace all gaskets (maybe including cylinder head gaskets)
- paint the engine in the original color


What would be recommended to do too, once the engine is out? Are there any weaknesses this engine has, I should take care about?

What I am thinking about doing optional, but I have no idea if really neccessary:
- replace the timing chain
- Regrind the valves (would improve compression)
- Resurfacing the cylinder heads
- cylinder honing
- new piston rings (would improve compression)
- check all bearing clearances

I checked Kanter Auto, they have almost all engine parts for rebuild. Also Cars LLC has the right gasket set: https://www.ebay.de/itm/174122853138
Ames has the most parts too. Any other classic part suppliers that can be recommended?

[Bill Hanlon]

Whether you replace the timing chain or not, I'd recommend upgrading the front crankshaft seal to a lip seal. Details here: https://www.pontiacsafari.com/L1Gara...ealUpgrade.pdf

I still have the alignment/installation tool that I had made when I did mine. I'll loan it out with a $100 deposit, gladly refunded when the tool is returned. You pay shipping both ways. You'll be around the 14th user.

Just remembered you are in Europe. It would probably be cheaper to have a machinist make the alignment tool than to send it across the Atlantic twice. One of the Pontiac guys had his machinist make one from some kind of plastic. I'll see if I can dig up the details.