Hair pulling transmission problem

[Leon79]

Hi everyone,

I bought a few years ago a Plymouth Volare SW 1977 with a slant 6 and a bad transmission. The transmission was staying in drive no matter what. In park it would fight the brake and kill the engine and in reverse as well. Neutral was drive and drive was drive.

Luckily the owner bought an other "brand new lost the receipt" transmission and i did the swap.

It drove well for a hundred of miles but the other day it did the exact same thing. Stuck on drive, no reverse no neutral...

Two different a904 with the same issue.

I checked the fluid level and ok.

The one i got bolted on is a bit newer i think cause the input shaft had fewer teeth and i had to change the torque converter.

Anyway i did not find anyone online with a similar problem and my last hope before ditching the car is you.

I live in France so repairs by a shop will be extremely expensive, those car are pretty exotic and finding a transmission will be difficult.

Does anyone know what can be the cause of all this and is there something I can do apart from rebuilding entirely the transmission?

Thanks for your help.

Leon

 

[AMC Diplomat]

I can only make guesses. My first guess is there's a problem with the shift linkage

 

[Leon79]

Thought about it but the linkage is moving freely and i can feel the gears shifting. In park the car is fighting against the transmission brake and in reverse it's worth it's fighting against something and it's killing the engine.

 

[Oldiron440]

Was the new transmission complete or did you need to swap parts?

Have you verified that the transmission mechanicly goes through the gear rage at the valve body without the vehicle running? Park is park, neutral is neutral, drive is drive etc. etc.?
Also verified the kick down linkage is adjusted correctly? Again without the vehicle running.

 

[Camtron]

Trying to drive in all gears is usually clutches welded together. Have you opened up the first transmission that went out?
Can always try to get it rolling in drive and slam it into reverse, can free up stuck clutch packs.
Worse scenario, it blows and you know it needs a rebuild.
Bad scenario, there’s no change at all and you’re in the same place.
Best scenario, it starts driving like normal and you know it needs a rebuild.

 

[Leon79]

Was the new transmission complete or did you need to swap parts?

Have you verified that the transmission mechanicly goes through the gear rage at the valve body without the vehicle running? Park is park, neutral is neutral, drive is drive etc. etc.?
Also verified the kick down linkage is adjusted correctly? Again without the vehicle running.

The tranny was complete.
I'll do all those verification and let you know and if nothing changes I'll try the unorthodox method of Camtron.

I'll think about rebuilding the original transmission myself. I never done that but I guess there's a first time to everything.

Last option is to swap the slant 6 with a 318 or 360.

 

[AMC Diplomat]

 

[Camtron]

The tranny was complete.
I'll do all those verification and let you know and if nothing changes I'll try the unorthodox method of Camtron.

I'll think about rebuilding the original transmission myself. I never done that but I guess there's a first time to everything.

Last option is to swap the slant 6 with a 318 or 360.

They’re very easy to rebuild as far as transmissions go. Between the factory service manual and the bench manuals available it’s a great first transmission to rebuild. Clutch spring tool, snap ring pliers, sockets, torque wrench, lip seal install disk, some assembly lube, and they come apart and go together easy enough.