727 speedometer cable leaking

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MoparMuscleGuy

MoparMuscleGuy

Still plays with cars.
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Hello, I have a leak where my speedometer cable screws into my 727 transmission. This is the first time I've had this problem. Before I started playing with it I thought I should ask for assistance. MMG
 
I had the same problem,fishey68 help me big time.there are 2 seals and the biggest thing is getting it clock right.dont worry he will be along soon hes the Man
 
As Snake said there are 2 seals and it can leak from either but the most prominent cause is the internal seal. When you have to take the speedometer pinion adapter out to replace a seal your better off replacing them both because even if it's just one leaking R&R'ing may cause the other to leak. Go to your favorite parts supply and buy a factory replacement outer seal, make sure it's orange as it's a special seal that ATF won't attack and buy an inner seal for a early to mid 70's GM turbo 400 (if they need an application tell them it's a 73 Chevy truck with a 454 engine and turbo 400 trans). It's the same dimension but has an inner spring to hold it tight against the pinion shaft. Mopar seals don't have the inner spring and are more prone to leaking. When you install them lube them up good with trans. assy. lube (Vaseline works too if you have no assy. lube) and install it in reverse order of removal. Here's a pic I modified showing the seals and the inner one that is problematic. Also make note of the clocking of the adapter housing before removal so you get it back in correctly. What I've found that works the best is to install it with the largest #'s located at the 6 O'clock position then rotate it until it lines up where it's supposed to be, assuming of course it needs to be on one of the positions with a lower set of numbers. Those #'s correlate with the tooth count of the speedo pinion gear.
 
fishy68 said:
Your welcome MMG. Always glad to help.
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I'll be putting the car on the lift in a couple days to see about fixing it. I've never pulled that area apart before. It doesn't look to bad, but I know if I need ya I can ask. Thanks, MMG
 
It's not hard at all but if you have any questions you can always ask. PM me for my ph # if you like. I'm available most any time.
 
Hey i got the same problem, do you guys have any part numbers that work? i am having a hard time finding a seal, i found one for my 70 dart with a 904 but i can't find one for my 65 coronet, measurements are: .250" ID .450" OD and .150" wide, let me know, i would appreciate it, thanks
 
70dart65coronet said:
Hey i got the same problem, do you guys have any part numbers that work? i am having a hard time finding a seal, i found one for my 70 dart with a 904 but i can't find one for my 65 coronet, measurements are: .250" ID .450" OD and .150" wide, let me know, i would appreciate it, thanks
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Have you tried your local auto parts stores? My local NAPA can usually get just about anything I ask for. If you can't find it locally try www.rockauto.com They have parts for a lot of older cars
 
Fitz73Chrgr said:
Anyone have the diagram that fishy posted? It's not showing up for me.

Thanks!
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It's a speedometer pinion gear seal if yours leaks at the cable nut on the trans.
Wouldn't hurt to have the large outer Oring for the adapter housing to trans case also.
I got them at a local trans shop.

pinionseals.jpg
 
I'm gonna try my local trans shop when time allows for that O ring seal. Spent yesterday cleaning it all up removing the whole assembly. Still leaks! But very much at a super slower rate.

Thanks for the picture!
 
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