1941 Problem shifting into reverse

[Jerry CLC#879]

I have a 1941 Cadillac with the hydromatic and the problem I have is that when trying to shift into reverse the transmission makes a grinding sound. I do not try to force it into gear as soon as I hear the sound I shift back to low. It shifts just fine into drive. I checked previous posts but could not find anything. I am wondering if there is a trick to these transmissions and I am being paranoid with the noise, but I do not want to break anything. Any help would be appreciated.
               Thank You, Jerry

[George]

Jerry, I dont know, which trans this year car has, was it the dual range hydro. Noises from the trans point to something serious. Something has to be broken, or loose. Looseness seems to be the obvious point, if the forward range is OK.... If the noise only occurs in reverse, then obviously that is the place to look. The first thing is to check the linkage adjustment,in case the park pawl is catching the teeth lightly when reverse is selected.

[Barry Wheeler #2189]

Doug left out...And THEN pull the lever into reverse. There is probably nothing wrong with the transmission, just getting used to it. I remember trying to shift one while checking out a car so equipped with a friend. I made all kinds of noise trying to back up, (and I used to drive a 41 Hydro every day to work.) I just had gotten out of practice. Put Dougs advice to use and youll soon be shifting like a pro. Good luck.

[Tod - North Texas CLC]

This is not a worrisome problem.  Hopefully, the guys who really know what they are talking about will follow-up on this, but I can tell you about my exposure to these transmissions.

I have a 1942 that still has the pre-war early hydramatic.  It will sometimes make the grinding noise when going into reverse, but I immediately go back into Low, and try again, and it will usually drop right in without a problem.  I thought that this was inherent to the pre-war hydramatics, but the 1947s that are in our club all exhibit the same behaviour.

Bill Ingler, Doug Houston and the rest of the knowledgeable flathead guys should be able to tell us that something or other is out of adjustment, and the best way to correct this problem, but I think that you will find that is a rather common characteristic on these transmissions.

Bill?  Doug?  Anyone else?

[Doug Houiston]

Here goes for about the fourth time. Dunno whats wrong, but somebody must be trying to tell me something.

It looks like you have the original trnasmission in the car, from your dscription. On all Hydra-Matics, from 1940 (Oldsmobile) throuigh 1950, the transmission has to engage before an attempt to shift into reverse position. On the prewar transmissions, there was no safety device to prevent going into reverse and damaging the reverse pawl and the reverse planetary drum. In the 1946 and later, there is a reverse blocker piston in the valve body which blocks the selector from going into the reverse position before the transmission engages. In all of those models, from 1940-1950, THE REAR WHEELS MUST BE TOTALLY OUT OF MOTION as you drop the lever into reverse. In 1951, a cone clutch device was added to the reverse selector and its possible to safely yank the lever into reverse as soon as the engine fires, without problems. I have a 51 transmission on one of my 41 cars, and its nice to be able to get reverse without a wait.

Now, if youre not sure of what transmission you have, check the following. Look at the transmission from under the hood on the driver side. If there is a large hex plug at about 1:00 on the front of the transmission case as youre looking at it, its postwar. That (regulator plug) wasnt on the prewar boxes. Also, if the selector lever detent positions are relatively soft, its prewar. On the postwar models, the selector detent was on the control valve body in the transmission, and the positions are very sharp and pronounced.

[Paul Ayres #5640]

Jerry - As Doug has explained, the early Hydramatics did not have a reverse block-out, so the proper way to shift into reverse is to shift first into low, as Doug explained, pause a couple seconds to allow the trans to engage and the inner parts to stop rotating, then  shift BRISKLY into reverse.  This will allow reverse engagement without the grinding.  Also, since this trans has no park position, you can use reverse to lock the trans.  Shift into reverse before you shut off the engine, then turn off the key, and the trans will be locked.  You must shift back into neutral to re-start the car.  Paul Ayres