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May have posted in wrong place. Now have 100 miles on my fresh engine and the trans has started leaking. I have pulled trans to
put a new o-ring on the flywheel & torus housing to solve the big leak but I am also dripping trans fluid around the shifter and kick down shafts. Would like to fix it while out of car. My Chilton book isn't very clear and the transmission guys around here have never worked on one. Is there a fix where you don't have to pull the pan and tear stuff apart? Thanks in advance.
Around 2800.00 plus my labor. New everything. Pistons, cam, lifters, bearings. Bored .030 over. Valve job. Expensive to build. If I had it to do over I might have put a later used Old's or a LS in it.
Location: Sherwood Park, Alberta, in the Great White North
Posts: 359
My experience with Hydramatics is limited, but in both cases where mine developed leaks, I eventually had to go an get it completely overhauled because once it starts to leak the pressure drop makes things slip. The last one I had done the reverse cone clutch went and I had all the gaskets redone anyway just as insurance. That was done at a generic Lo-Cost Automatic transmission shop, which is part of a nation-wide chain. It ended up costing me $500 to get that done. At the time it took me about 1/2 an hour of networking a phone to find a shop here in Edmonton Alberta that would take it on, you'd be surprised how many guys still know how to fix one of these things or are willing to take it on. (Surprising, considering how few Olds cars were sold up here then). The basic theories and technology hasn't changed much, it's mainly a question of getting parts. Apparently it's very similar to a 60s to early 80s Mercedes transmission. (DB bought the 4spd Hydramatic when GM retooled to the SlimJim)
Marc, it seems you got a really good deal. I had the hydro-matic in my 54 Olds rebuilt in February 2017 at a total cost of about $2,500. That was $450 for a shop to pull it out and put it back in. Then the 77 year old guy who rebuilt it charged me $2,000. It is very difficult to find anybody here that knows anything about these transmissions or is willing to work on them. My car is back with the transmission guy now getting the leak in the tailshaft fixed. My car has a 55 transmission in it that has a different design in the tailshaft than the 54. It was only used in 55 and 56 and has some parts that are very rare and hard to find. It took me over a year to find them and I finally found them at Fatsco Transmission (good guys). I am sure it would cost over $1,000 to have a even a Turbo 350 overhauled. If you can find anybody here that knows anything about these old transmissions is going to be well into their 70's.
Location: Sherwood Park, Alberta, in the Great White North
Posts: 359
Glenn, you're right, it's about $2500 to get one overhauled nowadays here too. That Hydramatic I had overhauled was close to 20 years ago and it was a basic job. It was just invasive enough that all of the gaskets needed to be changed. A buddy just had his 53 Hydramatic done from stem to stern and it cost him $2468. We got it back as a full drop in unit; the guy who did it is also at one of those transmission shop chains, but he's owned it since the 60s. He's trained his sons in how to do them as well, and most of his clientele are vintage and oddball cars. He makes good money and as he puts it, it's a good break away from replacing Dodge Caravan trannies all day long. He did my TH400 in my Electra, again for $2200, and it works flawlessly. I'll be taking my Hydramatic to him later this year. Mine still works, but if my buddy's was anything to go by, every gasket and O-ring in it was swollen to double it's size and not very effective. Seems a lot of people like using "stop-leak" in those things which ruins seals by swelling them. My 53 does also have some leaks, I just don't know how bad because it's always been on gravel or dirt.
Is there a fix where you don't have to pull the pan and tear stuff apart?
Unfortunately, there is a bit of "tearing apart" required. There's an "O" ring on the shaft inside the case retained by a ring. You'll have to remove the levers to access it. If the transmission is currently shifting properly (ranges and shift points), be sure to make a reference for the position of the levers before removal. Exact position replacement will be needed.
put a new o-ring on the flywheel & torus housing to solve the big leak but I am also dripping trans fluid around the shifter and kick down shafts. Would like to fix it while out of car. My Chilton book isn't very clear and the transmission guys around here have never worked on one. Is there a fix where you don't have to pull the pan and tear stuff apart? Thanks in advance.
You should be able to change the shift and throttle shafts without completely dismantling the trans . You will have to remove the pan and maybe the valve body . But that should be all .
I would advise getting a 1957 Oldsmobile Shop Manual . Much more detail than either Chilton or Motor's .
E-Bay has a good selection ; https://www.ebay.com/sch/i.html?_odk...anual&_sacat=0
Original printed copies are best .
Repaired leaks. Now high and dry. For any one who might need to reseal the shift shaft. I found out the hard way that you can replace the O-rings from the out side. I discover this after I pulled the valve body. I needed a new pan gasket any way. A Chilton and Motors manual both give incorrect info for this transmission. Must be for a later build as they state Dual Coupling thru '64. Any way, I have created another problem. Shift from 1 to 2 is ok. 2 to3 winds tight , wont shift unless I let up on gas. Same for 3 to 4 shift. I am thinking throttle pressure change but I done nothing but unhook it at the trans lever. Shifted fine before. Could I have done something when I took the valve body off? I did have trans upside down on the floor when I done this. Really don't see how that would matter. Any help is appreciated as always.
Repaired leaks. Now high and dry. For any one who might need to reseal the shift shaft. I found out the hard way that you can replace the O-rings from the out side. I discover this after I pulled the valve body. I needed a new pan gasket any way. A Chilton and Motors manual both give incorrect info for this transmission. Must be for a later build as they state Dual Coupling thru '64. Any way, I have created another problem. Shift from 1 to 2 is ok. 2 to3 winds tight , wont shift unless I let up on gas. Same for 3 to 4 shift. I am thinking throttle pressure change but I done nothing but unhook it at the trans lever. Shifted fine before. Could I have done something when I took the valve body off? I did have trans upside down on the floor when I done this. Really don't see how that would matter. Any help is appreciated as always.
I have a 1956 88 with the hydramatic trans and may be having a similar problem with my shifting but it starts to bog when pressing on the gas. It wont up shift on occasion and hasn’t happened all the time.
November 2nd, 2018, 02:07 PM
