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Plymouth P23 transmission Question


Dennis

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Our 1940 Dodge has a P23 engine which is finally running.  We have a few issues with timing, oil pressure and transmission.  

I'll limit this question to the transmission problem.  The trans will shift into 2nd & 3rd but not 1st or reverse.  With the trans out of the car the 1st/reverse lever can be moved slightly but not enough to allow shifting into 1st/reverse.

We have a transmission from a 1940 Dodge D17.  Can we use this transmission as a replacement for the Plymouth trans?

Thanks for any advice

Dennis 

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13 hours ago, Dennis said:

With the trans out of the car the 1st/reverse lever can be moved slightly but not enough to allow shifting into 1st/reverse.

 

 

Not sure how this will be fixed by a linkage adjustment.

 

Sounds like you already have it out, shouldn't be a problem to put the Dodge trans in

 

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42 minutes ago, Sniper said:

 

 

Not sure how this will be fixed by a linkage adjustment.

 

Sounds like you already have it out, shouldn't be a problem to put the Dodge trans in

 

That lever doesn't move very far in general. If they are trying to move it as far as the other shift lever they'll never get there.

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Also doubt there is a serious mechanical issue with the trans shifting into 1st/reverse.

Maybe the shift cover is installed wrong, springs/balls missing etc as already mentioned.

Or possibly you are not shifting it correctly with the trans  in or out of the car with the shift rods disconnected.

The forward heavy thick shifter  lever must be in the middle "neutral position.

It should snap accurately into the neutral detent position.

The slightly curled rear shift lever is somewhat loose and floppy when not hooked up to the shift rod.

Anyway with the forward lever in neutral grab the rear lever and firmly twist it clockwise hard...then push the other lever hard to the right or left...it will move an inch either way. Snapping into reverse or first gear positions.

Sometimes the input or output Shafts need a slight turn to help the shift into gear.

All this as long as the side cover is assembled correctly and no one has messed with the transmission.

These three speeds are a pretty trouble free unit.

If the trans will shift correctly by hand it's only necessary to adjust the rear lever shifter rod correctly with the transmission in the car.

 

 

 

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2 minutes ago, Dodgeb4ya said:

Also doubt there is a serious mechanical issue with the trans shifting into 1st/reverse.

Maybe the shift cover is installed wrong, springs/balls missing etc as already mentioned.

Or possibly you are not shifting it correctly with the trans  in or out of the car with the shift rods disconnected.

The forward heavy thick shifter  lever must be in the middle "neutral position.

It should snap accurately into the neutral detent position.

The slightly curled rear shift lever is somewhat loose and floppy when not hooked up to the shift rod.

Anyway with the forward lever in neutral grab the rear lever and firmly twist it clockwise hard...then push the other lever hard to the right or left...it will move an inch either way. Snapping into reverse or first gear positions.

Sometimes the input or output Shafts need a slight turn to help the shift into gear.

All this as long as the side cover is assembled correctly and no one has messed with the transmission.

These three speeds are a pretty trouble free unit.

If the trans will shift correctly by hand it's only necessary to adjust the rear lever shifter rod correctly with the transmission in the car.

 

 

 

I agree with the testing described.  Folks don't seem to grasp the 'selector' shift mechanism.  One lever actually does all the shifting, the other just selects the gear pair being shifted, 1-R or 2-3.

Edited by kencombs
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With both transmissions on the bench, we compared the shifting of the P23 transmission with the '40 Dodge.  We can feel and see the difference.  The rear lever on the '40 moves further and springs back when released.  Can't tell if it shifts into 1st but it does shift in reverse.  We'll remove the shift cover on the P23 to see if anything is broken or missing.

Thanks for all your advice.

Dennis

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We have the shift cover off.  Can only move the 1st/reverse rail if we rotate the drive pinion first. 

Anyone interested in seeing photos of the underside of the shift cover and the shift rails? 

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Both rails.must be in the neutral detent position before either rail can be moved forward or backwards.

1st/reverse is easy to move forward backwards..

2nd to 3rd much stiffer because syncro's must line up.

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8 hours ago, Dodgeb4ya said:

Both rails.must be in the neutral detent position before either rail can be moved forward or backwards.

1st/reverse is easy to move forward backwards..

2nd to 3rd much stiffer because syncro's must line up.

That is very true.  The OP may have to move the MDG in order to align the teeth of the low/rev gear to the cluster.  Since no syncros with tapered ramps to guide that one, they may just butt against each other until moved a little.  Sort of sounds like what was described.

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