Trans Fluid Leak Down Speedo Cable

The speedo cable nut is fairly tight but I have fluid leaking and running down the speedo cable then dripping onto the exhaust collector. How do I stop the leak?

70 727

Thanks

Is the O-Ring on the speedo gear shaft good and is the O-Ring on the gear housing good?

I will check both of them in the morning. I’m letting it cool down before I pull it off.
Thanks!

I couldn’t wait😀.
I pulled it off and a broken o-ring fell out. Got it replaced and will test it this weekend.
Thank you!

be aware there is an inner seal for the speedometer gear, it is held in with a spring clip. The lip faces inward. there is also an outer O-ring for the housing.

The leak appears to be coming from the cable/nut area. Then the fluid travels down the cable. I put two different diameter o-rings inside of the nut to try and seal it up.

The speedo housing is completely dry.

Thank you!

You need to remove the speedometer adapter from the transmission. Then slide the gear out and look into the bore of the housing. You will see a wire retaining ring and a small v-seal. That is the source of your leak.

This ....

Here's a pic of the seal and wire retaining ring.

Thanks guys!! I was having trouble visualizing where that seal was located👍

Seal part number is 2538588.

ATP part number is SO13, might be easier to locally source one of those.

If you, or someone else, needs the bog oring around the adapter that is ATP TO34

Thank you for the part numbers!!

Parking on a slant toward the front of trans helps too. Don't have a lot of fluid loss.

I just bought a seal kit from Eberg a couple weeks ago:

https://www.ebay.com/itm/324510752336

Yikes! $26 for shipping! Won't those parts fit in an envelope?

give me a day or so to look, i "might" have some extra of those seals in my parts cabinet.
if i do, i'll send them to the OP, gratis.

Thank you for looking!

Not sure where you are getting $26 for shipping, listing shows $4.30 for shipping.

Basically, $15 delivered. Or you can order the stuff using the ATP numbers provided at a local store. For a crap ton less.

Advance shows a 5 pack of the seals for $2.99, big oring is $2.19 for a 5 pack.

i found the internal o-ring, the one retained by the hair clip snap ring, and also the large o-ring that fits on the outside of the speedometer gear housing.
as to the one on the speedometer cable, well, i'm still looking. [for a speedometer cable to see what that o-ring looks like. i know there is one here, just in which "pile-o-stuff" is it in. ]
if you can't source one locally, i'll get it in an envelope for ya..........

There is no seal "on the speedometer cable" on the '66 and later. Outer seal on the adapter is an O ring, inner is a molded lip seal.

I will track one down locally, but thank you for looking 👍

No one said the eguy is cheap, that about 3.00 worth of parts BUT he's providing a service and get paid for doing so

Exactly. I don't mind paying a few extra dollars to get the right parts delivered right to my door, especially with covid. Most auto parts places around here are still on limited hours and nothing is in stock. So I have to drive to at least one store, place the order, and then drive back again to pick the parts up days later (and hope I got the right stuff). I just went through this with buying shocks - one store had fronts but no rears, another store had rears but no fronts. The distance to hit them both was 40 miles and I couldn't do it on the same night because the stores both closed at 6pm. I said the hell with it and bought them through Rock Auto.

I just ordered a set of 5 of the "ATP" #SO13 on Amazon for $4.61 and free shipping. My local stores had their own part number with minimal part description. Since some of you already confirmed the brand and part number, I know I have the right part coming.

Thank you again!!

I had the same problem and fixed it yesterday. I just got my 727 back from being rebuilt and I bought a used housing and gear which came with a new O ring and internal seal which was missing from the transmission. The housing came with a new seal and O-ring and it leaked and ran down the cable. Yesterday I pulled the housing back out and noticed there was no resistance when pushing the gear into the seal so I replaced it with the one the trans shop sent with me out of the rebuild kit. Now I could feel the seal againts the gear and the leak is gone. Some one must be making a seal with the wrong dimensions .

Another thing to look for is any lateral scratches (lateral meaning across) the areas where the seals sit. Bubba likes to use metal picks to remove the seals leaving the scratches behind, check the gear as well although I've never seen one with damage. If you find any and they are not deep, just polish them out leaving a "radial pattern"

you can remove and replace the internal lip seal [o-ring it is NOT ! thanks JK, for pointing out my mistaken nomenclature !] without removing the tiny hair clip retaining ring if you are super careful with the new seal and use very blunt, correctly sized for the job, probes.
just make sure both seals, especially the new one, are lubed up good.

I usually take the seal and retaining spring out, inspect, get the seal started and use a 1/4" deep socket to push it into place. Then start the spring and use the same socket to push it down until it just touches the seal. Be aware that pushing it in too far will distort the seal And yes lot's of lube is good

Thank you everyone! I hope to start on it later this week.

And yes lot's of lube is good....where have I heard this before??? Oh that's right...work

hmmm............

Does this look like the right creature? I was expecting one a little larger for some reason.
Picture too big but it measures about a half an inch in diameter.
Thanks

Dumb question: the cone shape of the seal goes away or toward the housing?
The black one that I pulled had the cone facing outward.

Thanks!

The cone tip / lip faces inward toward the gear. Not outward toward the cable.

Yes, they are that small.

Thanks!
The black seal had the cone facing outward! I marked it with a blue paint marker before I removed it from the housing.

The one on the lower right corner (looks dark brown) is how it should be installed into the housing(bottom side first) from the outside in towards the center of the trans.

The tan one if installed into the housing (bottom side first)as pictured would be backwards.

OR, The recessed side with the lip goes in first towards the center of the transmission Got it ?
then install the clip to just touch the seal holding it in place.

I think TJP did a better job of describing it but I drew a picture. LOL

IMGTX:
Thank you for the picture as that is the same orientation that I found the black seal. I will be installing the grey seal tomorrow night.
Thanks everyone!

Any lip seal like in the drawing should be installed so that any internal pressure will push the seal tighter into the shaft it is sealing. If you install it backwards pressure will tend to force fluid past the seal, same with front or rear main seals.

I'll politely disagree and refer to the old saying "A picture is worth a thousand words"
Great job IMGTX

And to the OP,
1. Do not forget to check for lateral gouges or scratches in the housing where the seal sits
2. The bottom of the o-ring groove on the gear housing
3. The surface of the trans case that the outside O-ring seals against
4. Finally the shaft on the gear itself where the inside seal rides. EDIT: I just looked at your picture again. the area where the seal has been riding is visible. I would polish that area again in a circular pattern. HINT: A drill motor on the end on the gear works great
5. Push the seal in gently until it stops
6. Do the same with the retaining ring being careful not to compress the seal as it will deform it. (I normally use an appropriately sized 1/4 drive deep socket / nut driver etc.)

Minor issues can be polished with 600 grit or a fine scotch brite pad etc. If required it should be done in a circular fashion so any residual marks are circular like the seal.
Gouges need the be filled with something similar to JB weld and the leveled using the above procedure