Speedometer cable leaking gear oil

[rrunnertexas]

Gear oil is leaking from the speedometer cable connection at the transmission my '35 Plymouth.

 

I'm assuming there must be an O ring or seal someplace that is worn or missing.

 

Looking for suggestions on how to get this fixed.  Pics attached.

 

Thanks!

 

[Sniper]

A factory parts book will show you.  It is pretty much an essential thing if you are going to maintain these old cars.  It will not only give you a part number to look for, but it will also show how things go together sometime, critical when decades of who knows whom has been fat fingering things.

 

That said, I was putting together a list of seals and gaskets needed to redo the one in my 51 Plymouth.  As it turns out the seal you may need is used from 35-48, part number 652840. which is listed in one of my books.  I can find no cross reference for that number though.  In my parts book it gives the following description

 

"Oil Seal, Speedometer Drive Pinion (chrome leather, 11/62 I.D.  37/64 in O.D.m .150 in thick)"

 

You might be able to go to a bearing supply house with those specifications and they might be able to find something suitable.  Or maybe someone else already has that info.

 

 

[rrunnertexas]

Sniper,

 

That is exactly the wording I was thinking but could not describe - Drive pinion oil seal.  Thanks!  The leak is coming from the pinion/cable and not the acutal case.  So, where in the heck to find one of those seals - ebay, NOS?

[Sniper]

Only listing I know of

 

http://dpmotorparts.com/list_parts.cfm?page=11

[sidevalvepete]

https://www.dpmotorparts.com/toys_2.cfm

 

Put snipers part no. in the search function with these guys. They have it in stock for $15. Sorry I'm not better at making the link go to exact page.?

[sidevalvepete]

.......you beat me to it. Lol

[rrunnertexas]

Excellent!  Thank you for the experience and advice/help!  Much appreciated!

[Sniper]

Well, minimum shipping is $15, plus cost of the part.  So your thanks might be premature, lol.  I'd try the bearing house myself.

[rrunnertexas]

Last night I pulled the entire speedometer assembly from the transmission to take a look.  What I found is what appears to be a fiber type material used as the seal instead of a rubber type.  I'm assuming the newer rubber type is the replacement for the original fiber?

 

Asking before an order for a replacement is made.  Thanks!

 

Pictures attached.

[sidevalvepete]

Maybe you could replace and repack in a carefully cut bit of felt into that seal......not that I have tried that myself though ?

[Sniper]

A set of these might help.  Or if you have the of the right sizes, empty shell casings make a nice hole punch too.

 

https://www.harborfreight.com/6-piece-hollow-punch-set-67030.html

Edited January 25, 2022 by Sniper

[JBNeal]

I believe the felt is supposed to slow oil flow to reduce pressure on the rubber seal...subsequent speedometer cable oil seals were of the double lip variety, where the oil pressure helped to push the rubber seal against the rotating shaft, and there was no felt used.

 

additional information - Speedometer Drive Pinion Sleeve + Seal

[rrunnertexas]

JBNeal - Looking a bit deeper at the felt, it goes all the way down into the "cup" part without any other seal.  I read the link you sent which is very helpful.  I'm thinking the Honda made seal will then fit in the place of where the felt is now.  Correct?

 

If so, then this may be the hot ticket to success and no more leak!

 

 

[JBNeal]

A comparison of the older felt + rubber oil seal and the newer rubber oil seal I linked to will show that although they look similar, the seals are not the same.  The metal adapter that screws into the transmission is referred to as a sleeve in the part manuals, and this sleeve was redesigned to accommodate the newer rubber seal, which eliminated the felt washer.  The newer rubber seal mounts inside the sleeve, with the seal lips contacting the speedometer pinion shaft, inside the transmission case, so that no external seal is required for the speedometer cable.

 

I am guessing that the linked NOS sleeve + oil seal was backwards compatible and was an upgrade kit back in the day to address the gear oil leaks at the speedometer cable in the older transmissions, as newer transmissions used this newer sleeve to accommodate the newer seal, which was a simpler yet more robust design that was easier to service.  I had acquired several unknown-to-me transmissions years ago in a trade with another Mopar gearhead who was liquidating his parts stash as his projects were done and he was moving to Oklahoma for work.  I noticed that several of these transmissions, manuals and automatics, had this same newer sleeve that was in the 3spd manuals in my B-series trucks.  Without doing any further research, I assumed that Chrysler upgraded their transmissions with this newer sleeve + oil seal arrangement as needed.  Truck 4spds had a different speedometer gear orientation that did not use the 3spd rubber seal, and the parts manual refers to it using a retaining nut instead of the sleeve.

 

additional information - truck 4spd speedometer gear nut

 

If'n ya had access to one of these newer sleeves, you could probably tell fairly quickly if your speedometer pinion gear would fit and could upgrade your transmission accordingly.