Bad gearbox leak

[Bryce Mcclintock]

Hi all , Ive finally got the plymouth up and running and have been on a few good runs .Unfortunately the gearbox is leaking quiet badly the leak apears to be coming from the front input shaft or perhaps somewhere around the gear selector plate , my question is what seals the input shaft the manual dosent depict a seal and i cant seem to find one listed to buy , is it common for them to leak around there ? Im going to pull gearbox out to fix seals at some stage ,at this point the output shaft seal is  not leaking should i replace it anyway or just leave it alone until it does leak . Also the universal boots on drive shaft have split completely so will have to be replaced also but was thinking replacing the the internal pin and ball parts at same time .how do i tell if they are at end of life or even need replacing  thanks 

[keithb7]

What year/model Plymouth are you referring to? Thx. 

[Bryce Mcclintock]

Sorry that was stupid to leave out 1952 plymouth cranbrook .standard 3 speed manual transmission 

[Sniper]

there is no seal, per se.  Some have retrofitted one.  There is a thread here with this very issue and shows the original way it is kept from leaking.

 

https://p15-d24.com/topic/50800-chasing-transmission-leak-48-p15/?tab=comments#comment-538887

Edited March 21, 2021 by Sniper

[Bryce Mcclintock]

Thanks really helpfull  

[DJK]

10 hours ago, Sniper said:

there is no seal, per se.  Some have retrofitted one.  There is a thread here with this very issue and shows the original way it is kept from leaking.

 

https://p15-d24.com/topic/50800-chasing-transmission-leak-48-p15/?tab=comments#comment-538887

Sniper, do you have any info on the retrofit seal for the input shaft. I have been seriously thinking about looking into a way to do that. all other leaks on my trans have been addressed with no issues.

[Doug&Deb]

Boots are available for the driveshaft. Cleaning and new grease is usually all that’s necessary for maintenance. Follow the procedure in the service manual.

[Sniper]

58 minutes ago, DJK said:

Sniper, do you have any info on the retrofit seal for the input shaft. I have been seriously thinking about looking into a way to do that. all other leaks on my trans have been addressed with no issues.

A set of calipers and sometime looking at shaft seals at Grainger might do the trick.  I found the post I had read about this, link.

 

 

[DJK]

Thanks Sniper, I find the search function lacking on this site, it is easier to google, which then leads to this site!! I have rebuilt hundreds of Nissan transmissions with seals in the input housing, on the Cranbrook it would require machining the housing to accept a seal along with polishing the shaft. dodge4bya mentioned a metal shielded bearing with the shield toward the inside, that didn't make sense. I will contact him. I maybe over thinking this, but around here on some long down hill sections, it seems like that is a recipe for a leak. Maybe drop the fluid level slightly???

Thanks again for your input, Dave

[Sam Buchanan]

1 hour ago, DJK said:

Thanks Sniper, I find the search function lacking on this site, it is easier to google, which then leads to this site!! I have rebuilt hundreds of Nissan transmissions with seals in the input housing, on the Cranbrook it would require machining the housing to accept a seal along with polishing the shaft. dodge4bya mentioned a metal shielded bearing with the shield toward the inside, that didn't make sense. I will contact him. I maybe over thinking this, but around here on some long down hill sections, it seems like that is a recipe for a leak. Maybe drop the fluid level slightly???

Thanks again for your input, Dave

 

I believe if you carefully seal the bearing retainer housing with a good gasket and make sure it is modified to drain properly that you won't have any oil leaking in this area. Downhill isn't an issue because the oil level in the tranny will be well below the mainshaft (unless you are driving down a cliff then you will have more serious issues than tranny leaks.....). No need to overthink this, just make sure it is sealed up the same way those smart Mopar engineers intended. 

Edited March 22, 2021 by Sam Buchanan

[plymjim]

Bryce, you do have a gasket between trans & bell housing, right?

Without this gasket the shifter rail holes in the front of the trans

will leak & could be your problem.