1951 Dynaflow Transmission rebuild

[Johnganderson]

 

My mechanic indicates that the Dynaflow transmission needs to be rebuilt. Can anyone on this post recommend a company to do the rebuild.

[Rusty_OToole]

Is this the same guy who tried to talk you into replacing it? How does he know it needs to be rebuilt? I believe you have never driven the car?

 

It is a pretty basic, 2 speed transmission much simpler than the 4, 5 and 6 speed jobs in new cars. But finding someone familiar with them, who has parts or knows where to get them, is another matter.

[61polara]

Greenville Transmission Clinic in Greenville, SC can rebuild it.  Your mechanic really needs a factory shop manual for an engine rebuild and he needs to read it.  I'm also curious how he knows it needs a rebuild.  

[Johnganderson]

Both of you are right, 

 

Rusty, initially when he started the engine we were all hopeful that we could run the engine for a period of time without a rebuild, however we had 2 lifters and rockers that were noisy and when he scoped the bottom end there was rust. In addition we were not getting the oil pressure that was needed on the top end.

 

Once we found out this information he recommended that the engine be rebuilt and I went with his knowledge and recommendation. he then suggested that instead of rebuilding this engine that we replace it with a V8 or v6 with a TH350 or TH400 behind. We did not want to compromise on the engine so it was my SWAG that we put the TH400 with a conversion kit behind the "Fireball", not his idea although he indicated that that might not be all that bad of idea. Then I posted on this sight yesterday and after reading 8 comments that were basically saying "What are you doing that for" that after all the modification were made that we could probably just rebuild the transmission and keep the car original.

 

These conversations all occurred over a 30 day+ period with much more thought than presented here.

 

My mechanic has indicated that we should rebuild only based upon his experience. The car has sat in a garage since 1966 and in his opinion when a car has not been driven for that period of time the transmission will fail. May run for a while but will fail in "30" days or so.

 

The engine is going to be rebuilt by a shop that is experienced in the Buick Straight 8 but the mechanic will remove and reinstall.

 

I will make sure that he has a shop manual, it sounds like I should have one to so that I can know what I am talking about in layman terms at least.

 

Thanks again Rusty and Dave...Your comments are much appreciated.

[davenc]

Fatsco Transmissions in Pine Brook NJ  can do the Dynaflow rebuild. They also sell Dynaflow rebuild kits if you want to do the rebuild yourself. I just completed a rebuild on my ‘54 DF with one of their kits. The kit was complete and had good quality components. The shop manual for your car will have complete step by step instructions for rebuilding the DF. It’s not particularly difficult, just a lot of parts. Patience and organization is the key. You can do this!

Having someone else do the rebuild is pricy, especially if you need to ship the trans to a rebuilder. 
Before you go down that path I would try draining and replacing the fluid and  see if the trans will come to life. What do you have to lose?

[61polara]

2 hours ago, Johnganderson said:

however we had 2 lifters and rockers that were noisy and when he scoped the bottom end there was rust. In addition we were not getting the oil pressure that was needed on the top end.

 

2 hours ago, Johnganderson said:

The car has sat in a garage since 1966 and in his opinion when a car has not been driven for that period of time the transmission will fail. May run for a while but will fail in "30" days or so.

You have a change and replace mechanic.  What did he do to try to pump up the two of sixteen lifters?  Yes, there should be rust in the bottom end after sitting for that long, but the important question is where. A couple of oil changes with additives should have cleared both issues.  Did he do this?  If they haven't started the rebuild of the engine, have it returned and reinstalled.  Pay this mechanic nothing, he is scamming you because of his lack of knowledge of old cars.  Take it home and drive it, then see what the problems are.

 

Join a local AACA region and they will guide you to competent mechanics for older cars.

[Frank DuVal]

1 hour ago, 61polara said:

You have a change and replace mechanic.

Sure sounds that way. A Dynaflow only uses clutches or bands to shift into Reverse and when you select Low. All other times it is the torque converter doing the work. And it just needs clean fluid. Dexron III aka Dexron-Mercron. Type A is NLA and has been since the early 70s. Type F has friction modifiers for shifting Ford transmissions (hence F), and since the Dynflow doesn't shift, no need for type F.

 

2 hours ago, davenc said:

Patience and organization is the key. You can do this!

Patience, Cleanliness and Organization.....😉   

 

Take pan off, clean screen and button it back up. Unless the ATF smells really burned and is dark brown, then yes, rebuild time.