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1957 Roadmaster, engine runs perfectly, new ignition, new plugs, new wires, new fuel pump, new carb, etc etc. However, upon acceleration there seems to be a vibration or shudder resulting in slow pick up. It has been suggested to me that it could be a torque converter damaged.

In reading up on the dynaflow I came across the fact that the index hole in the crank has to be aligned with the index hole in the flywheel. (is this correct???)

Secondly, did I put it out of balance when I turned the flywheel with a pry bar in order to put the torque converter drain hole at the bottom?????

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There are three bolts (and bolt holes) that attach the flywheel to the torque converter. The three bolt holes and the three access points in the flywheel for installing the bolts in the holes like up only one way. If you had the three bolts in place and tightened down, then turning the flywheel with a pry bar should not hurt or change anything. Yes, it sounds like you could have internal torque converter damage or maybe one of the three bolts has fallen out, which would unbalance things a bit.

Pete Phillips, BCA #7338

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You mentioned shudder and slow pick up. That could also be due to the drive clutch pack not holding on acceleration which could be the piston seal or low fluid pressure. A low fluid level might also cavitate the pump momentarily and sucking air and drop the line pressure which holds in the drive clutch. If it accelerates better under light to moderate throttle and shudders when throttled harder, that might be the clutch pack slipping. I am assuming this only happens in Drive and not in Low range. Tell us more history.

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adding some more "history".....the transmission leaks, has ever since I got the car. I almost...almost wish the transmission would quit entirely so that I would be forced to pull it out. However, I would rather have a rebuilt replacement ready to go in. I am starting the search up here for someone who knows Dynaflows and is not chained to a bed in some care home!! Car still seems overly sluggish on acceleration with what seems like a vibration when accelerating but not when cruising.

I am interested in any and all relevant input. Know anyone within a day or so drive of Winnipeg Manitoba that knows and works on dynaflows??

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I cannot help with the rebuilder, but adding a bottle or two of STP (blue bottle) will help slow the leak and improve function if due to low pressures.  Do this after the fluid change.  

This works for me and was recommended by my rebuilder mentor.

Willie

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Hmmmm....just received a overhaul price from Gene at "TransmissionsbyGene" in California ......$4895.00 in his shop. Seems a trifle rich....am I wrong?

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Ouch! That's crazy! Especially when Robert Trail successfully rebuilt his own on the kitchen table.

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Hmmmm....just received a overhaul price from Gene at "TransmissionsbyGene" in California ......$4895.00 in his shop. Seems a trifle rich....am I wrong?

Holy crap...run!

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Rebuilding your own is a good idea.  The vast majority of the rebuild is gaskets, measuring for wear and replacing, milling or machining what is needed. ( Which can be outsourced to a trusted machine shop ). We advocate purchasing a used dynaflow for the spare parts.  Tear into that one first as a learning tool, then set your sights on rebuilding yours. 

 

One approach is to Surgically clean the outside of the transmission.  Then, get a nice long bench or banquet table setup system going in the garage, shop or basement and then start dismantling and internally cleaning by section as per the shop manual dictates repeating this procedure going on down the table as you disassemble/clean all the while  keeping component sections in their perspective and designated place per section of removal.  When you get to the end of the long table or bench &  transmission case, then start back and reassemble as per the manual.  Take photos as you proceed.

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I know this is probably not the issue, but overfilling these Dynaflows can have just about the same effect as one that does not have enough fluid, with slipping and such. I speak from experience!

 

We just rebuilt our Dynaflow on our own, and had no dipstick for the transmission. So we just used the amount of fluid the shop manual said. Ran fine for about a month. Then one day the transmission was leaking all over the place from the pan, and slipping terribly. At first I thought the gasket was just junk, or that the transmission was overheating and blowing the seals, but after getting a transmission dipstick, turns out it was about 2 quarts overfilled. Drained it right away, got it to the right level, and the transmission hasn't slipped or leaked ever since!

 

Kind of weird that an overfilled transmission almost acts the exact same way one without enough fluid does. But at least it wasn't overheating like I thought!

Edited by Brandon T (see edit history)

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