What semi-auto trans and fluid drive oils do you use?

[MarcDeSoto]

If you own a 40s Chrysler, DeSoto, or Dodge, you may have a semi-automatic transmission and fluid drive.  Is 10 W non detergent oil still the best to use in the transmission?  Also, if you need more fluid in the fluid drive, what do you use? 

[DonaldSmith]

10 weight oil for the semi-automatic transmission itself.  (There may even be a tag on the transmission announcing the same.) 

 

Hydraulic Fluid 32, for the fluid coupling.  Tractor Supply Company, for one, has the fluid in various sizes.   I'm sure it's available other places.  It's the same fluid used in hydraulic pistons.

 

Some people say that the fluid never has to be replaced, and maybe so.  If you don't have to, don't do it.  

 

A few years ago I figured maybe I should, so I bought a big bucket of the Traveler's fluid from TSC.  

 

It's tricky draining the coupling and getting the new fluid in.  The plug is accessible through an access cover.   To drain the fluid, you have to remove the plug without losing it.  Rotate the coupling until the drain hole is at the bottom.  I didn't, and not all the fluid drained out.  I still have half a bucket left.

 

To get the coupling rotated to the bottom, and otherwise to rotate the crankshaft accurately, I removed the mesh on the right side of the bellhousing, and used a pry bar (gently) against the flywheel teeth.  (You cannot get very accurate in nudging the starter.)  

 

 

[MarcDeSoto]

Donald,  thanks for the excellent advice and pics.  That looks like an awesome DeSoto Suburban you have there.  Did you know that famous director Cecil B. DeMille bought one!  On the fluid drive, yes if it doesn't leak, don't replace it.  I would just like to open it to check that all the fluid is still in there after 67 years!  But I'm afraid if I open it I might create a leak!  I just found a good source for getting the 10 W oil non detergent on Amazon and they don't charge for shipping.  They have oil by Accel and Kendall.  Thanks, Marc.

[DonaldSmith]

See the first photo I posted above.  When the plug is accessible, it is at the high point of the fluid.  Sort of like filling a differential or transmission.  

 

You may need the trick with the pry bar for getting the flywheel and coupling in the right position.  If you don't see the fluid, probe for it with something like a pipe cleaner. Just don't drop it in.

 

In the words of Leslie Nielson,  "good luck... we're all counting on you."  

[MarcDeSoto]

no problem for me in turning the fluid drive.  I've got a large socket wrench on the crankshaft nut.  Thanks again.  And don't call me shirley! 

Edited January 11, 2015 by MarcDeSoto

[greg g]

This might be one of those instances that proves the expression "let sleeping dogs lie"  If it's not leaking leave it alone. That plug may lead to Pandora's box. 

[MarcDeSoto]

I finally got 12 quarts of Accell SAE 10 non detergent oil.  I plan to use it in my semi-auto transmission and maybe for engine break in.  the reason I hesitate is that the bottle says it is not designed for use in gasoline engines made after 1930!  I'm only planning to use it for the first 1000 miles, but maybe I should consider Royal Purple Break In oil?

[Don Coatney]

MarcDeSoto, on 15 Jan 2015 - 01:18 AM, said:

I finally got 12 quarts of Accell SAE 10 non detergent oil.  I plan to use it in my semi-auto transmission and maybe for engine break in.  the reason I hesitate is that the bottle says it is not designed for use in gasoline engines made after 1930!  I'm only planning to use it for the first 1000 miles, but maybe I should consider Royal Purple Break In oil?

 

I thought the break in oil issue had been beat to death in this linked thread.

 

http://p15-d24.com/topic/37786-what-oil-for-new-engine-start-up-and-break-in/

 

But is sounds like you did not hear the answer you wanted to hear. So I now suggest you call all the lubrication manufactures for there recommendation then follow there advice and buy the one with the highest prices and the best art work on the container. That way your engine should feel good, be happy, and comfortable. 

[Dave72dt]

I only mentioned Royal Purple because I know they make a product for that purpose.  It's on the label.  I think Joe Gibbs does too.  I've never used either one, have built and started a lot of engines and have never wiped out a cam or brg using anything other than the oil it's going to get routinely in it's life and the initial assembly lube.  You're way overthinking this process.  Dump your 10W in, fire it up and run for 20 minutes at 1500 to 2000, get it up to op temp, dump it, refill with  whatever you intend to run permanently.  After sitting that long, I suspect a bit of surface rust on the cylinders, so the rings will seat really fast, most of the rebuilding contaminants will be flushed during the initial firing and you should be good to go.  You can repeat the 20 min  run process if you want, up to you.

[MarcDeSoto]

Good advice guys!!!  I really like Don's advice to buy the most expensive oil with the best art work on the bottle!  I think I'm going to go with Dave's advice here. 

[meadowbrook]

For those who did change the fluid drive fluid, did you notice any difference?

My '50 Dodge has the fluid coupling and standard 3 speed manual and it sure feels like the fluid coupling will drag the engine down if I let the clutch out without moving.

My idle is set as around 650 in Neutral but drops to 400 or so if I let the clutch out and prevent the car from moving.

 

I am wondering if with age the fluid gets thicker or thinner and if that makes the fluid drive harder to slip. I checked the level and it is correct and I even tried to brake torque it, and I think the spec is that from idle the engine should rev up to ~1100 RPM but mine fails to go over 800.

 

So it seems it is a 'grabby' unit. I am tempted to change the fluid but since it does not leak and the car really drives nicely, I hesitate. Plus I rarely use the fluid drive feature anyway, preferring to drive it like a normal stick.