Has anyone found a "modern" oil seal for the output shaft on a 53 dynaflow?  I bought one from the Buick Farm NOS and it is a piece of leather pressed into a steel shell and then the leather is cut a slite bit smaller than shaft.  I am sure this is a NOS seal it is even in a box dated Nov. 1952.  I know the dimensions of the dynaflow seal are way off from modern seals but I am just hoping with my fingers crossed!

54fins,

I thought I was the only one with this problem.  I'll work with you on this.  I have not reserched this for years.  I will get into some old manuels and look around again.  We are going up to British Columbia in September so I have to be done to get some break-in miles on it.

Suntree - welcome aboard.  I haven't dealt with it, but you'll want to deal with the torque ball seal.  That will prevent the transmission fluid from making its way to the differential.  As for your other discussion points, I can't comment as I don't have sufficient knowledge.  Good luck.

Hello, I am new here.  Your dynaflow story was referenced in a Team Buick forumn.

I have a 53 Twin Turbin Dynaflow.  We drove 3500 miles on one trip last year, it used, leaked about a cup of fluid.

It sat for two months in the shop and leaked about 2 1/2 quarts.  Looking at the oil schematic, there is reference to a one way check valve that keeps the torque convertor fully charged.  I suspect this is where the large amount of fluid is coming from.  The main housing fills up about 3 inches over full,  then leaks out the speedometer gear output and then runs down the torque tube and contaminates the rear differential.  I drilled a small hole in the torque tube near the front of the diff. and let the oil leak out before it gets to the diff.  

I have been putting up with this for about 15 years.  Has this problem been addressed before on here?  I believe this check valve is in the valve body.  Is the valve body removable.  I am hoping for a check ball with a spring behind it.  I could drill out just a little to clean up the seat , maybe with a bit of laping compound and a slightly larger check  ball to fit the larger hole.

Great post/thread.
Many Many thanks professor
steve apter

An impossible task some say.

As a follow up to "Pulling a 54 Nailhead",  here's Professor Nailheads advise on Sealing a Dynaflow.

THANK YOU BILL!!!!!!!!!!

(Please feel free to reply with additional comments and tips)

                   DYNAFLOW TRANSMISSION OIL LEAKS

This article is intended to cover just the basics on Dynaflow oil leaks and is not intended to replace the shop manual.  The first task is to get your expectation in perspective – most Dynaflows leak some even after rebuilding.

Dynaflows tend to leak in four places, some all at once.  The locations of leaks and the remedy is as follows:

OIL PAN GASKET:
The OEM gasket was cork and after many years becomes soaked with oil and even tightening the pan bolts does not help.  New replacement gaskets are better material and this is an easy fix to do yourself, even easier that most engine oil pan gaskets.  Before installing the pan, look carefully at each bolt hole for evidence of overtightening.  If the surface is bulged up, hammer or file it smooth with the rest of the gasket surface.

ACCUMMULATOR CAPS:
There are two accumulators, one on each side of the transmission near the front.  The caps look almost like drain plugs.  The OEM gasket for these is a thin metal gasket.  Leaks from these tend to be small, but can usually be fixed with just more tightening of the cap.  Use a breaker bar with a 6-point socket and give a good tug.  CAUTION: If you disassemble the accumulator becareful as there is a large spring under the cap!  Typically it is not necessary to take them apart, just to tighten the cap.

TORQUE BALL SEAL:
This subject was covered in detail in the December 2009 issue of the Bugle and so it will not be repeated here.  Aaron Toth did an excellent job and included great photos that should be if help if you do this job yourself.  If the OEM rubber boot becomes brittle, which it will over time, this can be the largest oil leak of the Dynaflow.  In Toth’s article he correctly points out the upgraded replacement seal that has been available for some time.  Even if you find an NOS factory rubber boot, it is not recommended that it be used.  Remember, it may be NOS, but it is 50+ years old and would likely have a short life if used.

FRONT PUMP SEAL:
This can be the second biggest leak of the Dynaflow and certainly the most difficult to replace.  The first three leaks can be fixed with the transmission in the car, but this one not only requires the transmission removal, it requires major disassembly.  Once the transmission is removed, the torque converter needs to be disassembled in order to get it off of the input shaft.  (Dynaflow converters are NOT like more modern coverters that pull off directly and can even be left on the flywheel when the engine and transmission are separated.)  Even after the converter is removed there is a fixed shaft that extends through the pump and seal.  While the seal can be pried out and replaced at this point, since it is such a labor intensive job just to get to this point, it is recommended that the pump be replaced with some incremental labor.

SUMMARY:
While Dynaflows may seem like a complicated piece of machinery, and they are, they actually are easier to work on than the other automatic transmission of the era like Hydramatics, Ultramatics, etc.  I rebuilt my first Dynaflow when I was still in high school.  I placed cardboard around the perimeter of the garage floor and started at one end.  As I took parts off, I slid the transmission down the line keeping each part in the sequence that I took it off.  When I was down to the empty case, I cleaned all parts, being careful again to keep the sequence exact.  Once cleaned, I examined parts for wear and replaced and suspect parts.  Then I reassembled the transmission in the reverse order.  It worked fine and when I sold the car after adding about 20,000 miles to it and the Dynaflow was still working perfectly.

Bill Bicknell, BCA #738
3/16/10