1947 Plymouth P-15 transmission leak

[caddyman68]

The transmission on this car leaks oil out of the front quite badly. I even have it underfilled by about 1".

I put in new bearings that matched the old ones, new gaskets, & rear leather seal from a Ply. vendor. Even the rear seal leaks.

I never had this problem with any of the ford or gm trannys I rebuilt.

Any ideas anyone? And thank you in advance. Larry

[suntennis]

There should be a gasket between the engine and transmission which will stop some of the oil that can leak from the front of the transmission. Another place for leakage is visable just below where it bolts to the engine and it is a shaft for a transmission gear. This area can be cleaned and sealed with some automotive sealant.

[caddyman68]

Yes, I have the new gasket glued to the tranny. I installed a new soft plug in the one hole but the other shift rod hole had to be left open.

I will be pulling it back out this weekend. Maybe I can find something.

[Dodgeb4ya]

These area's on the 3 speed can be a cause of leakage...

1. No gasket between case and bell housing

2. Speedo seal in adapter hosing-it's NA

3. O-Rings at shifter cover lever shafts

4. Case to extension housing gasket-always use a new proper gasket

5. Shifter cover gasket

6. Rear seal-Will leak if the replacement is NOS hard leather/or hard old rubber-even if soaked in oil for a couple days, also can leak if replacement seal lip rides on a worn groove on the companion flange- will require a Speedi-Sleeve

7. Countershaft can leak at press fit at front of case-seal with a good sealant.

NOTE...There is no seal at the front input shaft as on GM and Ford-just a reverse slinger groove in the bearing retainer.

Bob

[Niel Hoback]

There should also be a gasket under the front input shaft bearing retainer. It's thickness determines the end play in the shaft, but there has to be one to keep the lube from leaking. The retainer itself has to be oriented with the drain on the inside pointing down.

[Dodgeb4ya]

There should also be a gasket under the front input shaft bearing retainer. It's thickness determines the end play in the shaft, but there has to be one to keep the lube from leaking. The retainer itself has to be oriented with the drain on the inside pointing down.

This gasket is very important-missed that one.

[DJ194950]

good points all!

if one of your possible leak areas doesn't fix this then drain and put grease it.no more leaks!! not really!!

i've had several mopar trans that leaking at custer gear shaft at front of trans. gasket does not cover it and the gasket i've seen have a split anyway on lower edge. bell housing cover it? if a solid gasket were made?

one i worked on had to drive this shaft rearward a far as possible(tailshaft will stop much travel) clean will brake clean and coat opening with permatex twice before leak was stopped.

last thought or question: does your imput shaft bearing have a cover on the outter side?. will not stop 100% of oil but greatly cuts it way down, so that the properly oriented drain in in support plate can return excess.

good luck.

doug

[Redmond49]

I had my transmission rebuilt last year. It's leaking badly out the front. I have the proper gasket between the transmission and the bell housing, it does not appear to leaking from the other locations listed above. I seem to remember being told not to use sealant on the front because the one open whole is a breather. 

 

Edited April 11, 2020 by Redmond49

[Ulu]

It's the oil return hole. If it's blocked, the trans will drip oil.

Trans breathes elsewhere.

[Sam Buchanan]

On 3/29/2011 at 5:40 PM, caddyman68 said:

The transmission on this car leaks oil out of the front quite badly. I even have it underfilled by about 1".

I put in new bearings that matched the old ones, new gaskets, & rear leather seal from a Ply. vendor. Even the rear seal leaks.

I never had this problem with any of the ford or gm trannys I rebuilt.

Any ideas anyone? And thank you in advance. Larry

 

I successfully stopped the leaks on my P15 tranny, here is the thread:

 

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

 

The key was modifying and sealing the bearing retainer:

 

 

 

 

[Sniper]

Along these lines, what's a good source of a complete seal kit?  Best (pn 5076) doesn't have the shift lever seals or the speedo seal.  Never messed with one of these transmissions so i don't know what all should be in the "kit".