ATF Leaking from Speedometer cable mounting ring

[Joe M.]

I installed a new speedometer cable and there was no gasket. I was told that it was a compression fit and would not leak. I also installed a new speedometer gear and a new o-ring on the mounting bracket. It is leaking as bad as it did when I had the old cable and old o-ring and nylon gear.

I have tightened the knurled ring on the cable as tight as possible. It appears that there is nothing to stop fluid from leaking out the center of the nylon driven gear. It slips into the PG case with no seal of any type. Any suggestions, besides wrapping a grease rag around the cable (that is my solution now).

[Joe M.]

Re: ATF Leaking from Speedometer cable mounting ring

Followup: I replaced the o-ring at the periphery of the "bullet" when I installed the new speedo cable; did not stop the leaking. There was a small groove inside the bullet that looked like a place to insert a tiny o-ring, but I was told at the time that the originals did not have an o-ring inside the "bullet." I had the PG rebuilt last fall with all new seals so I would be surprised if I am getting leakage past the torque converter into the back of the PG, but it must happen when the car sits in the garage for a month.

[Edward J.]

Re: ATF Leaking from Speedometer cable mounting ring

Joe , I am not sure if your P/G is a cast iron or the aluminum , sometimes you can get a later housing. Which has a seal built into the housing to stop leaking around the gear. Ed

[Joe M.]

Re: ATF Leaking from Speedometer cable mounting ring

I have a cast iron PG in my 1960. I found a thread in the archives that listed two part numbers for seals that go inside the housing/bracket that holds the "bullet" in place. I know that I replaced one o-ring between the bullet housing/bracket and the tranny case. It seems like there should be an o-ring inside the bullet to stop ATF from going through the driven gear and through the bullet. There is a tiny "lip" milled inside the bullet, but I was told that there was no seal there; maybe in later years of PGs.

[Joe M.]

Re: ATF Leaking from Speedometer cable mounting ring

The o-ring shown in the photo is the only seal that I replaced. I think there should be another micro o-ring inside the bullet, but not certain.

[Ken A.]

Re: ATF Leaking from Speedometer cable mounting ring

The correct "bullet" has a lip seal on the outside that the tip of the driven gear fits thru. Find the correct part & you can toss the rag.

[Joe M.]

Re: ATF Leaking from Speedometer cable mounting ring

I purchased the lip seal from local Chevy Parts Dept. Even though I replaced the outside o-ring 11 months ago, I will install a new one when I remove the bullet.