Where can I find SAE 10w motor oil for my 1950 Desoto Fluid Drive Transmission ?The owners manual says this is supposed to be replaced every two years and I cannot find it anywhere . Is there a source of this oil ? Nobody seems to make it anymore.
Could SAE 5-20W be used safely as a substitute?
Please be aware that I am talking about the trans. not the torque converter . The torque coverter is supposed to safely take Dextron III as a substitute for the original Chrysler fluid. I do not plan to replace this since replacement is not recommended in the owners manuel . Any opinions on this?

Dave:

30W non-detergent motor oil works perfectly fine. I've been using it for 20 years in these transmission gear boxs, including the 1950 DeSoto that I've put over 100,000 miles on over the past decade.

Chrysler power steering units in the 1950s used 10W motor oil, but there was a service bulletin that said to use 30W in hot climates, and I'm betting there was a similar bulletin for our transmissions.

Look down this message board list and onto the additional pages, and you'll see a couple of lively discussions of all things Fluid Drive.

JON

Hi Dave,
I have both a 1950 Chrysler Imperial and a 1951 DeSoto and I use 10w in both the transmission and the torque converters...both run superbly....no leaks, etc. I am in New England and perhaps the Dextron III works better in the hotter climates....I have had no trouble buying the 10W oil here...I get it by the case for around $1.79 per quart through my local NAPA store. Good luck with your MoPar!!!

I have tried two NAPA stores in the Chicago area . All say that only 20w motor oil is available. I have tried other places as well . I even contacted Penzoil/Quaker State directly which said they no longer make this weight oil.
Could you tell me more about the oil you buy from NAPA . What is the brand name? Do you have a Napa part or inventory number ? My Napa stores say I am asking for a Product which does not appearin their computer inventory.

The local NAPA store here carries the oil as a regular item...the container does not say NAPA on it, rather Warren SAE-10. The address is Warren Oil Co, Inc. Hwy 301 North, Dunn, NC 28334. Perhaps you can contact them and see if there is a local distributor in your area for their oil. I have seen this offered for $7.50 a quart!!! As I said before, they sell it for around $1.79 which is more realistic.

Thanks for the information about the Warren oil company .Based on my experience in trying to find 10w motor oil , it makes sense that only a small oil company would produce this stuff. I will begin my hunt in the Chicago area and let you know how it turns out.
Lastly, does anyone have a opinion about the adviseablity of changing the torque converter fluid. The original manual does not call for changing this stuff.Should I leave well enough alone . Also , Which is best to use as a replacement- Dextron III or 10W Motor oil? I have seen both being recommended.

My choice is the 10W...I have it in both my 50 Imperial and my 51 DeSoto...I have checked with many sources (DeSoto Club Discussion Forum)including my 1950 Chrysler shop manual and all reccomend the 10W...others do suggest the Dextron as an alternative, but as long as the 10W is avaliable, thats what I use. As to changing the oil, I did it on both of my cars as a matter of course for the age and do not plan on doing it any more....the mechanic who did the change for me said it was black and felt it was a wise thing to do.

Tractor Supply Company (TSC) carries 10W non-detergent oil. I bought some at the local store here in Florida. I know they have stores in Illinois, not sure where in relation to Chicago, a bit north of my expertise. They are on the web at http://www.mytscstore.com/.

Rich

I did locate a source of Sae 10w non-detergent motor oil in the Chicago area .Thanks to those who suggested a farm supply store . This oil can be purchased at Blaine'S Farm and Fleet Stores . The brand name is Mystik and is manufactured by Citgo Petroleum Corporation, Tulsa , Oklahoma , 74102 .Blaine's has a web site and has stores throughout the great lakes area . The stores can be located through this site. Blaine's also carries Sae 30w non detergent oil.