1950 Plymouth Deluxe P-20

[Surge]

 

Hello all!

I'm having issues with the transmission shifting. When car is off, i can run thru the 3 speed without any issues. When car is running, i get grinding trying to get Reverse and 2nd gear. The transmission was rebuilt several years ago as was the engine. Seems the clutch is not totally dis-engaging. We've tried all visible adjustments and feel maybe adjustment must be needed to the clutch itself.

If i remove the clutch cover plate, can it be adjusted from there? Any thoughts welcome.

Thanks!

[Ivan_B]

Yes. First order of business, remove the clutch cover and ask someone to press the pedal. With the pedal up, the disk should be firmly sandwiched between the plate and flywheel. With the pedal down, you should be able to freely spin the disk with a flat screwdriver. If this is not the case, clutch is either our of adjustment or is otherwise not disengaging.

I would also recommend draining your gearbox and checking for "treasure". 🙄

Edited May 11 by Ivan_B

[Sam Buchanan]

The transmission mounts may be sagging and throwing the shift linkage out of adjustment. Follow the procedure in the service manual for adjusting the linkage, that may fix your problem. 

[vintage6t]

Just a thought, maybe it doesn't like the type of gear oil in it. It's worth checking for compatibility.

[Surge]

I did remove the clutch cover late yesterday,  Waiting for friend to come by tomorrow and pursue. Will keep you posted on progress.  Thanks all!

[Sniper]

I look for, at least, a 0.060" gap between the clutch disc and pressure plate with the clutch pedal fully matted.

[Surge]

Thanks Sniper!  

[Ivan_B]

1 hour ago, vintage6t said:

Just a thought, maybe it doesn't like the type of gear oil in it. It's worth checking for compatibility.

I suspect that it will still shift without grinding even if there is no oil... At least for a while 😅

Also, the TS is probably aware that there are no synchros on the first and reverse, and he is likely shifting through high/low, as necessary.

[Surge]

...update.  based on the feedback from you (thx!) we first checked to see if we were getting disengagement of the clutch.  Turns out we needed to extend the clutch adjustment rod which, to me seemed wrong as I felt it should stay stock.  However, we ran out of adjustment with its current length so we added a temporary extension and that worked to get the clutch separation we needed.  next, we had a terrible time trying to adjust the gearshift selector rod to get the transmission to go into reverse.  While on jack stands, we eventually got it dialed in but...when I put the car on the ground, we lost reverse again and now cannot get it back.  This is very baffling.  we did notice the assembly of the gear selector rod (i.e. double nut, block and spring) is very sloppy.  The car has 44,000 original miles and both the engine and transmission have been rebuilt.  what am i missing?

[Ivan_B]

Hmm, so the clutch was not disengaging? It is probably worn way out, if the original rod is no longer long enough. Or something was assembled incorrectly. Before you start playing with the gear selector rod adjustment, are you able to shift the gears pulling the levers by hand?

[Surge]

Ivan, Thx for your note.  Yes, we were able to shift the gears pulling the levers by hand

[Sam Buchanan]

There is a rubber grommet in the shift linkage that has probably deteriorated and allowed everything to get sloppy....or it may be entirely missing.

 

I'm not sure why adjusting the linkage on jackstands would be an issue but I would make the adjustments while the car is on the ground.

 

 

[Ivan_B]

4 minutes ago, Surge said:

Yes, we were able to shift the gears pulling the levers by hand

Ok, then something is probably wrong with the lever adjustment. I do not get what would make a difference shifting in the air, versus on the ground. Is the linkage routed properly and not being pushed/pulled when you lower the car? I assume that when you shift on the ground, the car is under load? You might want to check whether or not the lever at the box actually moves all the way it supposed to, when shifting from the cabin, versus when shifting by hand

[Surge]

Thx Ivan.  The gear shifter control rod seems to be working as required, and as you had noted about the rubber grommet, that seems in very good condition.  It is adjusting the gearshift selector rod that is giving us issues. 

 

Ivan, interesting comparison with the earlier pic you had shared.  My lever and rod are reversed to the set up on yours.  I wonder in my reassembly if I put this together wrong.  thoughts?

Edited May 14 by Surge
added pic

[Surge]

Ivan, gong back in time, i found an older pic of my setup prior to disassembly and it is reassembled accordingly, I think I'm ok. 

[Ivan_B]

So the issue is resolved, now?

Also, it was Sam who shared the picture, so he is the one who resolved the issue (if this was, indeed, the problem).

[Surge]

Hi Ivan,  

 

unfortunately not.  according to the manual, the pic i shared of the gear shifter control rod, basically just controls the horizontal position of the shift lever hanging off the steering column inside the car.  i believe my issue is with the gearshift selector rod. more diagnosis needed. 

[Ivan_B]

Okay, sorry I am not very familiar with the shifter selector adjustment. Let's wait for someone with more knowledge to reply. I assume that you've already gone through the complete adjustment procedure outlined in the manual?

[Surge]

Hi Ivan,  thx again for your contributions.  yes, we did follow the brief explanation in the manual.

[Sam Buchanan]

The gear selector rod is the one that has to be in correct adjustment for all gears to be engaged. This adjustment is pretty sensitive, at least it is on my car, a very small adjustment can be the difference between finding or not finding 1st and reverse or 2nd and 3rd. Keep working with it until you find the sweet spot. I don't think your clutch is the problem here, you may want to return that linkage to the original configuration.

 

 

Edited May 14 by Sam Buchanan

[Surge]

Hi Sam!

 

Thanks for your feedback. the short answer is we got it working later this afternoon...yippee yahoo!  The solution appeared to be both, getting the gearshift selector correct and once set, it wouldn't go into 2nd/3rd. So we realized the clutch plate was not disengaging fully. So.........we gave it a couple turns and for the first time, drove the car around a parking lot.  I'd share the video but the file is too large.

 

Having said that, I agree with you that I need to get the clutch adjustment lever back to normal which. i will do after our sons wedding on June 14th.  I need the car for the event.

[RobertKB]

22 hours ago, Sam Buchanan said:

The gear selector rod is the one that has to be in correct adjustment for all gears to be engaged. This adjustment is pretty sensitive, at least it is on my car, a very small adjustment can be the difference between finding or not finding 1st and reverse or 2nd and 3rd. Keep working with it until you find the sweet spot. I don't think your clutch is the problem here, you may want to return that linkage to the original configuration.

 

 

This adjustment of the gear selector rod is very important and it sounds like you now have it correct. In the shop manual (do you have one) it says to adjust the first nut so there is no slack and then back it off half a turn. Then tighten the second nut to lock in place. Make sure the first nut does not turn then. Best to use two wrenches. 

Edited May 15 by RobertKB

[Surge]

Hi RobertKB, thx for your note.  yes I do have a manual and that adjustment gave us anxiety due tot he sensitivity of moving that nut.  hopefully all stay well for a while as i break in the newly rebuilt engine, trans and clutch.

 

Cheers!

[DJ194950]

Surge

 

Do you really understand how these trans actually shift gears?

 

I ask because I know of no other companies trans that operate the way these do.

 

1. one lever only moves a very small amount and it Only selects if  the other shift rod  will be determining weather you are selecting 1/2st gear or / rev. gear - - Or the 2nd or 3rd. gear choices.

 

Having a hard time today explaining, maybe some other s can do better I am sure!  🤔

 

The shift Selected rod can be quite touchy on adjustments which is greatly accentuated with motor free movements and rod play.

 

DJ

[Surge]

Hi DJ,  if you would have asked me this question a week ago I would have answered [no].  However, given what i have experienced (hands-on) with friends and a super knowledgeable car guy (87 yrs old & friend), i have learned a ton.  I am thankful to have had the input from folks like yourself on this forum, combined with friends knowledge.

 

Cheers!