@markkubancik Thanks Carl, this is very helpful. This all started when I brought my DeSoto into a local shop that works on older Mopars for a front en...

I actually purchased the 1940-1948 DeSoto Factory Repair Shop Manual. They refer to a piston type and a diaphragm control system in their test procedu...

Thanks John! I will take a look at this and run some tests.

Les, Mystery solved by another blog on p15-d24.com. See the attached pic where kickdown is circled (lower right) and anti-stall is circled upper left....

I would appreciate it Les. She has not run right for a few year now (started with fuel system issue) so a few days won't make a difference. However, I...

Les, I have been told that the 1949 and later transmissions have a different wiring setup, which has two wires connected to the anti-stall. Owners ear...

Unfortunately it did not work. The only thing that actually got her to up-shift was removing the fuse on the fender. She up-shifted perfectly but was ...

Les, I just checked the car and I see exactly what you mean. Someone has made some modifications as the connector probably broke at one time. I wish I...

Les, I will try your recommendation. Meanwhile, is it possible to get a pic as to how your 49 is connected? I have owned my car for 43 years and never...

Thanks Tim! I found it. I was looking on the opposite side of the tranny. Sucker was clogged big time. Appreciate the help!

Gary/DeSoto Club Members, I am experiencing the same upshift issues on my 49 1st series S11 that has been described in this post. It started as an ...

I've am still dealing with an issue with my fluid drive not upshifting to second and fourth gears for quite some time now. I recently located and spok...