thegnu Posted February 25, 2018 Share Posted February 25, 2018 Hello , I have searched the forum trying to learn about this transmission I have in my roadmaster , its a cast iron 2 speed dynaflow an something feels off about it to me an its driving me nuts . I drove the car about 20 or so miles before I began my work on it an it dosent seem to me that this transmission shifts at all , I put it in drive an it wont shift . but if I put it in low an pull out from a red light then manually shift it I feel a slight difference as it goes into drive . am I loosing my mind here ? will this trans shift on its own like a newer powerglide or will I be shifting it from low to drive normally ? I only found 1 article that hints at it needing to be shifted manually ON WIKI ! (not sure if I want to trust that ), I don't want to damage it by doing this or if its needing rebuilt I want to take care of that . it dosent seem to be slipping but over all it feels a lil sloppy when accelerating only . is this normal ? the only experience I have with any gm 2 spd trans are the ones from the very late 60's an early 70's . Link to comment Share on other sites More sharing options...
NC-car-guy Posted February 25, 2018 Share Posted February 25, 2018 when you get to highway speeds does it sound like it's woundup? I never feel mine shift when driving. I figure as long as it takes off good from the get-go and it doesn't sound wound up at 65 miles an hour... must be working Link to comment Share on other sites More sharing options...
50jetback Posted February 26, 2018 Share Posted February 26, 2018 (edited) A Dynaflow transmission doesn't change. The " L " is an EMERGENCY LOW which is selected manually and under normal driving conditions does not need to be engaged. Edited February 26, 2018 by 50jetback (see edit history) 4 Link to comment Share on other sites More sharing options...
Pete Phillips Posted February 26, 2018 Share Posted February 26, 2018 "drove the car about 20 or so miles before I began my work on it an it dosent seem to me that this transmission shifts at all , I put it in drive an it wont shift . but if I put it in low an pull out from a red light then manually shift it I feel a slight difference as it goes into drive " You have described exactly the way it is supposed to work. Sounds like all is normal. Pete Phillips, BCA #7338 3 Link to comment Share on other sites More sharing options...
Gene Brink Posted February 26, 2018 Share Posted February 26, 2018 Don't forget that the '55 was the first year for variable pitch stators that felt much like a lower gear when engaged (NOT as low as the low position though) by flooring the gas pedal giving a noticeable improvement up to 50 mph or so. If your transmission is working properly you should feel something like this when you floor it. If you don't feel anything like that the shop manual gives instructions on how to adjust the linkage (connects to throttle linkage) so it will properly engage. Assuming this works it sounds as though your transmission is working correctly. I can advise that you don't want to shift from low to drive on a regular basis - especially if you do so under full throttle - unless you enjoy removing/replacing transmissions (which I did six times when I was much younger and felt the "normal" position for the gas pedal was tight against the floorboard). 3 Link to comment Share on other sites More sharing options...
old-tank Posted February 26, 2018 Share Posted February 26, 2018 Get an owners manual and a service manual. 6 Link to comment Share on other sites More sharing options...
thegnu Posted February 26, 2018 Author Share Posted February 26, 2018 thank you all for the info ! I do need to find a service manual , so next question where can I find a reprint ? there is a big swap meet coming up in april near by an I would like to have one sooner or I'd much rather have one sooner than that provided I can even find one . Link to comment Share on other sites More sharing options...
Leif Holmberg Posted February 26, 2018 Share Posted February 26, 2018 Why buy a copy when you can buy an original for less. https://www.ebay.com/itm/Buick-Shop-Manual-1955/162908614878?hash=item25ee1c30de:g:LlgAAOSw0bJZqrJs&vxp=mtr Leif in Sweden 1 Link to comment Share on other sites More sharing options...
Matt Harwood Posted February 26, 2018 Share Posted February 26, 2018 Sounds like it's working properly. Dynaflows don't have two "gears" like a PowerGlide. Most people who drive them for the first time think there's something wrong and that the transmission is slipping. It's an unusual sensation if you're used to feeling a noticeable change between gears. The Dynaflow doesn't work that way and the high and low ranges aren't "gears" in the traditional sense. If you put it in L and accelerate a bit, then move it to D, you will feel a "shift" but that's not really what's happening but it does tell you that the transmission is working properly. Just leave it in D and let it do its thing. It will be a bit more syrupy than expected, but that's how they were. Hope this helps! 2 Link to comment Share on other sites More sharing options...
trimacar Posted February 26, 2018 Share Posted February 26, 2018 (edited) I once had a beautiful original '57 Buick with the Dynaflow. It had less than 20K miles from new, and drove and looked like a new car. This was in the late 1970's, so it wasn't even that old then! I took it on a tour, and a fellow fell in love with it. He later called me, asked if it was for sale, I said sure, and he came over to test drive it. As mentioned, there's no discernible shift point. He got all upset, asked me why I didn't tell him the transmission was bad, he wouldn't have wasted his time. I tried to explain the concept of the Dynaflow, but he wasn't buying it, figuratively or literally, and left, mad at me. Sheesh..... Edited February 26, 2018 by trimacar (see edit history) 3 Link to comment Share on other sites More sharing options...
avgwarhawk Posted February 26, 2018 Share Posted February 26, 2018 I liken the Dynflow performance to an electric golf cart. The golf cart...one steps on the peddle and it simply goes and continues to pull without any discernible change with gears or anything. The Dynaflow is the similar. One steps on the pedal and it pulls the vehicle upwards of ticketable speeds without a peep/feel of shifting. There is no shift. 2 Link to comment Share on other sites More sharing options...
Guest Posted February 26, 2018 Share Posted February 26, 2018 Low gear on this transmission operates at twice the pressure of the drive circuit. That's one big reason to be careful when changing from low to drive. The drive section is singing the ZZ Top song "They got me under pressure!" And we do want to protect those poor seals designed for 100 psi in the drive circuit that are slammed with low gear 200+ suddenly! Link to comment Share on other sites More sharing options...
thegnu Posted February 26, 2018 Author Share Posted February 26, 2018 (edited) wow ok , thank you all so much . I an very new to anything this old that hasn't been "hot-rodded " even as my old 47 dodge wrecker has a 700r4 in it . but I did not have much of a actual truck there when I found it . Edited February 26, 2018 by thegnu (see edit history) 1 Link to comment Share on other sites More sharing options...
Frank DuVal Posted February 26, 2018 Share Posted February 26, 2018 Sssssmmmmmmoooooooottttttttthhhhhhhhhh is what a Dynaflow should be! It was designed to not have a gear change. The Hydramatics of the day had a distinct shift. Buick wanted none of that! It does the torque mutiplying through the 5 piece torque converter. I can tell you, having driven a 56 Special in my youth, the accelerator pedal activates the pitch change in the torque converter by mechanical means when it approaches "floored" position. The linkage does not care what "gear" is selected, moving the accelerator will change the pitch of the vanes. So, it DOES HAVE passing gear in Low and Reverse shift positions! Make sure you have lots of space when you test that in Reverse! It is fun. You can win some bets with the "My car has passing gear in Reverse". 2 Link to comment Share on other sites More sharing options...
thegnu Posted February 27, 2018 Author Share Posted February 27, 2018 6 hours ago, Frank DuVal said: So, it DOES HAVE passing gear in Low and Reverse shift positions! Make sure you have lots of space when you test that in Reverse! It is fun. You can win some bets with the "My car has passing gear in Reverse". HAHAHA NO WAY ! . not testing that I love my buick too much . 1 Link to comment Share on other sites More sharing options...
Kosage Chavis Posted February 27, 2018 Share Posted February 27, 2018 Good info here. I am learning a lot. But I have a question...the fact that the dynaflow doesn't shift, is there a lot of drag when driving at highway speeds and you take your foot off of the accelerator? Thank you. Link to comment Share on other sites More sharing options...
Beemon Posted February 27, 2018 Share Posted February 27, 2018 Fluid friction is minimal at cruising speed where the torque multiplication is near 1:1 crankshaft speed. It's not as fast as you'd think it would be off the line, but I have had no problem at all keeping up on the road. The 322 and Dynaflow are a pretty good couple and I drive my car the way Willie instructed me to when I first got it - like I stole it. In Low, though, you can feel the drag. I don't ever feel any drag in Drive but I know its there because I start to slow down going down hill at 35 MPH on weak inclines. 1 Link to comment Share on other sites More sharing options...
Kosage Chavis Posted February 27, 2018 Share Posted February 27, 2018 1 hour ago, Beemon said: I don't ever feel any drag in Drive but I know its there because I start to slow down going down hill at 35 MPH on weak inclines. Cool, as long as you can't feel it. Link to comment Share on other sites More sharing options...
Frank DuVal Posted February 27, 2018 Share Posted February 27, 2018 BTW, I learned about the passing gear in Reverse by reading the Owners Manual! Check it out here, if you do not have one: https://www.hometownbuick.com/portfolio/1956-buick-owners-guide/ "If Variable Pitch is required in Reverse, depress the accelerator pedal as explained in "D" and "L" above..." To a teenager, that is an invitation to operate the car as GM told me! 1 Link to comment Share on other sites More sharing options...
buick man Posted February 28, 2018 Share Posted February 28, 2018 (edited) … and a little more trivia ... apparently for 57 internal stator linkage changes made off the line launches in L a thing of the past and ineffectual which had been the standard practice for hot foots prior to 57 … however with the new stator changes delivered more low end grunt and too the engineers also tweaked the stator launch pad surge change while in D under full highway WOT to assure for any needed highway quick passing which at this rpm took advantage of the 364's enormous torque and especially if equipped with the Century, Super or Roadmaster's version of the 364 i.e. hotter lobby cam, different higher domed n cut pistons, new profiled 1.6:1 rockers from the previous years prvious1.5:1 and the kick-in higher 10:1 compression all neatly packaged and delivered via a big mouth thirsty 4-bbl carb via the 2507S Carter or the Rochester 4 g… rendering a very noticeable surge bang albeit softened by it lardy 2-1/2 tons but while rolling it got the job done …. - uncle dave Edited March 1, 2018 by buick man (see edit history) 1 Link to comment Share on other sites More sharing options...
NC-car-guy Posted March 6, 2018 Share Posted March 6, 2018 All this leads me to believe that a dynaflow behind a v8 with true duals, would sound pretty weird, as I am very used to the exhaust noise changing with shift points on my harley and other vehicles. Link to comment Share on other sites More sharing options...
Frank DuVal Posted March 6, 2018 Share Posted March 6, 2018 I don't know about "weird", as I heard the bubbly sound of many 54 to 58 Buicks with duals (Roadmasters) and Dynaflow in the years 1958 to 1968 in my neighborhood. You could tell them apart from the Cadillacs, Oldsmobiles, Pontiacs and other makes easily. My family's '56 was a Special, so Dynaflow with a single. They sound "normal" to me! 3 1 Link to comment Share on other sites More sharing options...
Beemon Posted March 6, 2018 Share Posted March 6, 2018 9 hours ago, wndsofchng06 said: All this leads me to believe that a dynaflow behind a v8 with true duals, would sound pretty weird, as I am very used to the exhaust noise changing with shift points on my harley and other vehicles. The exhaust noise on a dual exhaust Dynaflow car does shift in tone when the secondaries kick in. 2 2 Link to comment Share on other sites More sharing options...
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