I'm Steve I just bought a 1955 Buick special 4 door. When I bought the car the guy told me that the car had a slipping issue. it's an automatic dynaflow transmission. When we took it for a ride he showed me how when he puts it in D, the engine will rev up and the car doesn't move, he continued to show me that if he starts driving in Lo once the car starts driving he moved to D. Fluid is Full and Clean! The car runs amazingly! does anyone have any idea how hard is this to repair? or any place in philly area I can take my sweetheart to get repaired? Also I got the Shop manual and it seems very simple to work on this ******, I'm thinking about buying the master kit for ftasco and doing it myself. Thoughts?
so do you know bout takeing the rear ende out and jacking it bac to disconect from the ****** parts are spendy and this is no powerglide to repair good luck
I use the term "Dyna-saur". I have a 63 Riviera with one and it is hanging in there.I would like to change over to a 700R4 one day.
You can try checking the high ac***ulator and seeing if the check ball is stuck or the gaskets are leaking. Short of that, its most likely the bands inside the ****** that are shot. Mine does the same thing, L an R work fine, but D is just like being in neutral even after fixing everything externally accessible. Going with a 700r4 and 3rd gen camaro rear end instead. A good rebuild will run u probably 2k if u can even find someone who knows enough about dynaflows to do it, u can convert it to open driveline with a modern ****** for about 1k or less.
Is replacing the Dyna Flow with a 3 speed any simpler/cost effective than converting the driveline to a modern set up?
Like was stated above. When they work right they are great. My 56 rides like a dream. But a rebuild will be costly. Good luck.
Removal of the Dynaflow, as was mentioned is no picnic. The torque tube suspension makes alot of work to get the transmission out. As far as the slippage, well the problem could be the high ac***ulator, the direct drive clutch, and perhaps the stator linkage. If the stator linkage is not correct, the stator could be in the high angle position and make it behave like it is slipping. I am thinking more in the high ac***ulator/direct drive clutch area. I believe there is a port on the high ac***ulator that an oil pressure gauge could hook to. This would at least show if the ac***ulator is getting the apply pressure. If no pressure, then the valve body may have a stuck valve in it. If you think you can tackle the removal of the transmission, then parts are not anymore expensive than other early transmissions.
I got the Transmission rebuilt by a Precision Transmission in NJ, Great guys Great work!!! car runs awesome now!! They said the clutches were wore to hell and the bands needed to be adjusted, I bought the master rebuild kit from fatsco, they put it in.
The Dyna Flow's were made at another GM plant which also turned out the first series of the Chevy Power Glides. When GM had a HydraMatic plant fire they moved their production over to the Dyna Flow plant. We have a '53 Pontiac with what we later found out was a Dyna Flow when it was being rebuilt. It is still in the car and doing its thing after almost 200,000 miles. Normbc9
The hydramatic fire haulted production, till GM moved into the old Willys Willow Run plant. Willys had transferred production to Kaiser's Toledo, OH plant, so the Willow Run plant was available. I don't believe hydramatic ever was produced in the dynaflow/Powerglide plant. 53 Cadillacs and Oldsmobiles used Dynaflows during the haulted production, but 53 Pontiacs used Powerglides during that time.
In the Rivi you'd be much better off with a ST/SP400 out of a 64-66. Bolts to the engine with no adapter and minimal other work. If you can find a complete 3 speed setup maybe. Might be able to find a 3 speed parts car to get all the parts from. Trans, shift linkage, clutch pedal set up, etc.
get hold of FATSCO in New Jersey......they have antique automatic kits and parts....they advertise in Hemmings.
Same case trans (with the Nailhead pattern on it) as a TH400 was made through '69 and sold by GM to other carmakers, including Jeep, it pays to research.
Oh really? As I have posted before on here... A source for TH400 ******s: wanted to give everyone a heads up on a good place to look for TH400 transmissions. keep an eye out for jeep pick-ups and wagoneers 1965 to 1972. they have the same bell housing as a 401 nailhead and are th400's. you can unbolt the transfer case adapter and bolt on a 4" tailhousing and your ready to go! the holander number is # 1331, so start looking. i had never seen one till today and stumbled across one. Also Rolls and Bentley you are correct about this trans bolting up to a nailhead, but the output shaft should be a course spline on the jeep & about 3.75" longer than a 2x2. Dave the one i found was out of a 1970 jeep p/u but the output shaft is the same length and spline as my 65 buick trans st400 i have! what do you think the deal is with that! maybe it was changed or something. Yea, sounds like someone changed the shaft to be able to use a later GM transfer case. Good deal for you tho. Just checked on the jeep cores I have & they both have the long course spline output shafts. But you will want to overhaul it anyway, so thats the time to switch shafts.I got tons of the 2x2 shafts if you need some. Dave Most of the nailhead cases in Jeeps have the fine spline short shaft used with the 4" extension housing for Buicks. the exception being the Quadratrac transfer cases. You can also find them in CJ7's until 1980. Even stranger, the Jeeps with a 350 Buick in them used the Nailhead case, with an adapter to bolt to the 350. this is the adapter that might be reversed and used to fit a BOP stick housing to a nailhead. Don't know that it would work, never tried it, May be impossible, I really don't know. The guts will interchange from any T400 to any other T400 case. there are differences. The Buick valve body will hold the trans in the gear selected, and not "blow" shift like a chevy T400.The ST400 parts will fit too, with qualifications. you have to use the ST pump with the ST convertor, and the is an orfice plug that has to go in an oil p***age behind the pump at the top of the case. Also, you can use a ST 300 convertor in a ST 400 to get more stall out of the trans. The ST 400 convertor is 13", the ST 300 convertor is 11"
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