ledfootslim

OK, now I'm confused again. I have a 1948 Desoto S-11 with a fluid drive transmission. It seems that Mopar slapped fluiddrive on just about anything that sat still, so there are a million different sources saying a million different things. It isn't a three speed, but the "regular" low and high range that you read about. I don't know the differences between the M5 or the M6. I just know there are only three positions in the tree: reverse, low or power range as they call it, and high or driving range. In my MoTors manual it says to fill the fluid drive coupling with 10 weight oil, and the transmission with 90 weight. The oil that I drained out of the tranny didn't look very thick though. Please bear in mind guys, I'm eighteen and this is my first project of my own. My grandad doesn't have any experience with Mopar transmissions, so I would love a definite answer from one of you guys!

Totally.......I have always heard to use 90 weight for the actual tranny and 10 for the fluid drive coupling.....right guys?

Okay, I lied. I took out the drain plug after my last post, and there was maybe a little under a quart of oil in it. I am gonna pick up a few quarts of 85-130 tonight when I go get tires on my Pontiac. Keep your fingers crossed that this will solve my problem, and that I didn't screw something up! :-)

Okay guys, shes dry as a bone! I got under there amd took off the middle plug from the diagram Shel posted, and there was no juice at all that I could feel. Is this the one that takes 90W oil?

Hey thanks shel! I'll check that tomorrow! Is that the one that takes 90w oil?

It didn't have a service manual. And my 1935- 1949 MoTors manual said that you check the fluid by prying off a screen and then turning the engine over till you can see the plug. The only screens I could find were two on the bottom and side and you really couldn't put liquid in them, but I think there may be another on top. Surely they wouldn't make it so you'd have to take the floorboard out to check the fluid!?!

None of this really sounds like my problem- I really thought it might be the governor not letting me shift to fourth, but I don't think it would go 45 mph or so without shifting. I know this isn't a race car, but shouldn't it have more get-up-and-go than that? Has anyone else had a problem similar to this? Also, I had all the throttle linkage and everything off for the rebuild; is there something I could have done that prevents it from shifting whenever I lift my foot?

Hey everybody, first off, I have really dug being part of this group, but now I need some help from all you knowledgeable ninjas of mopar- I recently finished thge engine work on my 1948 Desoto S-11. Shaved the warped head ninety thousands, forty thousands overbore, split the manifold, etc, just pretty much hopped it up like they would have in the early days of hot-rodding. It runs pretty swell, but I just had it out driving around the dirt roads where I live, and when I made it to some blacktop, it started getting funny. I could get it up to about forty or so maybe, but then it would start sounding like the engine was revving way too high, like I was going about ninety. Lifting my foot off the gas wouldnb't shift it, using the clutch didn't do anything, I don't know if it is still something wrong with my engine, or if the transmission just isn't shifting. I stick it into first for getting started up the hill in front of my shop, then clut h and shift into high when it levels out. Presumably, it should shift at about 23 miles and hour from most accounts, by just lifting your foot off the gas,and with a resounding clunk, from what I've heard. Mine does not:-) . I pulled back the carpet, and found there were two ways to access the tranny from above, via two ports on the right side of the hump. One gives access to the three solenoids, and a plug,and the upper one gave access to a large rubber plug, which I popped out, bumped the starter until the plug lined up, and found that that hole was full of the proper light oil. Could any give any help here!?! What else should I check? Should I be driving it differently? What does the plug beside the three soylenoids access? It consists of a cap, a spring underneath that which sets on a little stem, and no fluid at all that I can see. Sorry for the lengthy spiel, but I was wanting to show this girl by the fourth of July. I've searched everything the web has to offer, so I hope you guys can give me something fresh. Thanks!

I removed several of the rear springs (especially two massive overload springs) and added 2" blocks on the rear of my '48, and she looks fine!!!!

Sweeeet! Mine is a '48, but pretty much the same thing. The 236 is a great engine, I definetley wouldn't get rid of it- unless you have plans for a '50's Desoto Hemi. The Desoto's are very similar to the Chryslers of the same era- until you get a close look at them! The grill is so much more awesomer, the interior (especially the dash) is no comparison and all they need is to be lowered a little and driven! If you are on the hunt for trim, look for any mopars of the same era as your car, the fender trim, front and rear, and almost everything else is interchangeable, with a little finagleing!

I ran throught the whole system on my '48 Desoto S-11, and finally had to find a longer spring for the master cylinder. After that, I had a firm pedal and am stopping just fine!