Author Topic: M-21 lube leaking out of the speedo cable  (Read 7253 times)

sixt9x33rs

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M-21 lube leaking out of the speedo cable
« on: August 16, 2009, 02:22:52 AM »
After running my car for about 20 miles in City traffic I have gear lube leaking off the speedo cable just before the cable attaches to the speedometer underneath the cluster. Any idea what would cause this? I am using Royal Purple synthetic lube. I checked the level and it is not over filled.

Thanks
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Stingr69

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Re: M-21 lube leaking out of the speedo cable
« Reply #1 on: August 16, 2009, 10:25:54 AM »
I tried royal purple and it was slightly more noisy and leaked for me as well. We could argue the reasons but bottom line is I would go back to GL-4 dino 90Wt and look at replacing the O-ring on the speedo gear holder.  Leave the speedo cable attached, loosten the tiny screw that holds the retainer and swing the retainer out of the way, then use the speedo cable to pull the whole thing out so you can get the O-ring replaced.

Definately go back to the GL-4 90Wt gear oil. Synthetic is not good for the brass in your transmission. 90Wt will be quieter, it will leak less, and the brass synchro rings will be much happier.

-Mark.

sixt9x33rs

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Re: M-21 lube leaking out of the speedo cable
« Reply #2 on: August 16, 2009, 01:09:01 PM »
Thanks for the input.
'69 RS Z/28 Olympic Gold, 711
Flat hood no spoiler, black top, endura, 4:10
POP 39,000
69 X77 Z/28 69 711 Original Paint Unrestored
'69 X66 Convertible Cortez Silver 712 black top Endura, auto, bumper guards, am/fm rear speaker 44k miles

JohnZ

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Re: M-21 lube leaking out of the speedo cable
« Reply #3 on: August 16, 2009, 04:49:02 PM »
There should also be a pressed-in rubber seal in the end of the speedo "bullet" where the cable ferrule screws on to keep gear lube from "climbing" the flex shaft.
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sixt9x33rs

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Re: M-21 lube leaking out of the speedo cable
« Reply #4 on: August 16, 2009, 09:33:51 PM »
Thanks John I will check that.
'69 RS Z/28 Olympic Gold, 711
Flat hood no spoiler, black top, endura, 4:10
POP 39,000
69 X77 Z/28 69 711 Original Paint Unrestored
'69 X66 Convertible Cortez Silver 712 black top Endura, auto, bumper guards, am/fm rear speaker 44k miles

sixt9x33rs

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Re: M-21 lube leaking out of the speedo cable
« Reply #5 on: August 16, 2009, 10:25:46 PM »
There should also be a pressed-in rubber seal in the end of the speedo "bullet" where the cable ferrule screws on to keep gear lube from "climbing" the flex shaft.
John do I have to unscrew the cable from the bullet to get to the rubber seal?

Are these parts I can buy at NAPA?

Thanks again
'69 RS Z/28 Olympic Gold, 711
Flat hood no spoiler, black top, endura, 4:10
POP 39,000
69 X77 Z/28 69 711 Original Paint Unrestored
'69 X66 Convertible Cortez Silver 712 black top Endura, auto, bumper guards, am/fm rear speaker 44k miles

JohnZ

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Re: M-21 lube leaking out of the speedo cable
« Reply #6 on: August 17, 2009, 04:27:37 PM »
There should also be a pressed-in rubber seal in the end of the speedo "bullet" where the cable ferrule screws on to keep gear lube from "climbing" the flex shaft.
John do I have to unscrew the cable from the bullet to get to the rubber seal?

Are these parts I can buy at NAPA?

Thanks again

Yes - unscrew the cable ferrule from the "bullet" and you should see the black rubber seal. Don't know offhand if NAPA carries the seal separately or not. The "bullet" is called a "fitting", and is P/N 3869912 (includes the seal), in group 4.338. The seal itself is P/N 3869910.
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sixt9x33rs

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Re: M-21 lube leaking out of the speedo cable
« Reply #7 on: August 18, 2009, 10:47:59 PM »
There should also be a pressed-in rubber seal in the end of the speedo "bullet" where the cable ferrule screws on to keep gear lube from "climbing" the flex shaft.
John do I have to unscrew the cable from the bullet to get to the rubber seal?

Thank you very much.

Are these parts I can buy at NAPA?

Thanks again

Yes - unscrew the cable ferrule from the "bullet" and you should see the black rubber seal. Don't know offhand if NAPA carries the seal separately or not. The "bullet" is called a "fitting", and is P/N 3869912 (includes the seal), in group 4.338. The seal itself is P/N 3869910.
'69 RS Z/28 Olympic Gold, 711
Flat hood no spoiler, black top, endura, 4:10
POP 39,000
69 X77 Z/28 69 711 Original Paint Unrestored
'69 X66 Convertible Cortez Silver 712 black top Endura, auto, bumper guards, am/fm rear speaker 44k miles

JohnZ

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Re: M-21 lube leaking out of the speedo cable
« Reply #8 on: August 19, 2009, 02:13:32 PM »
Photo below shows the end of the fitting where the speedo cable ferrule screws on; if you look closely at the end of the plastic speedo gear, you can see the black rubber seal.
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jl8dale

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Re: M-21 lube leaking out of the speedo cable
« Reply #9 on: August 19, 2009, 02:23:31 PM »
Awesome pic John.

I have the same problem in one of my Pace Cars with oil under my dash around the speedometer and wasn't sure why it was happening.

Thanks for your insight on this.
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click

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Re: M-21 lube leaking out of the speedo cable
« Reply #10 on: August 19, 2009, 03:18:35 PM »
A few more pics of speedo leaking issue. Mine is off TH350 but same problem, leaked down onto my foot while driving on a 2500 mile trip to a car show in Seattle. Chev.dealer replaced the bullet and all the seals and O-rings, dry ever since. :)



Click is Jim , central Minn.  Moderator at Team Camaro www.camaros.net

68Zproject

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Re: M-21 lube leaking out of the speedo cable
« Reply #11 on: August 22, 2009, 08:05:52 AM »
A picture is worth a thousand words.  I didn't know about that one in the end of the bullet.
68Z28

sixt9x33rs

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Re: M-21 lube leaking out of the speedo cable
« Reply #12 on: August 22, 2009, 07:00:49 PM »
Thanks for the pictures guys. That really helps explain the situation. Now I just need to find the time to fix it.

'69 RS Z/28 Olympic Gold, 711
Flat hood no spoiler, black top, endura, 4:10
POP 39,000
69 X77 Z/28 69 711 Original Paint Unrestored
'69 X66 Convertible Cortez Silver 712 black top Endura, auto, bumper guards, am/fm rear speaker 44k miles

sixt9x33rs

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Re: M-21 lube leaking out of the speedo cable
« Reply #13 on: August 24, 2009, 06:29:42 PM »
There should also be a pressed-in rubber seal in the end of the speedo "bullet" where the cable ferrule screws on to keep gear lube from "climbing" the flex shaft.
John do I have to unscrew the cable from the bullet to get to the rubber seal?

Are these parts I can buy at NAPA?

Thanks again

Yes - unscrew the cable ferrule from the "bullet" and you should see the black rubber seal. Don't know offhand if NAPA carries the seal separately or not. The "bullet" is called a "fitting", and is P/N 3869912 (includes the seal), in group 4.338. The seal itself is P/N 3869910.
John thanks for the part numbers. NAPA had just the seal. I will intall it and see how it works
'69 RS Z/28 Olympic Gold, 711
Flat hood no spoiler, black top, endura, 4:10
POP 39,000
69 X77 Z/28 69 711 Original Paint Unrestored
'69 X66 Convertible Cortez Silver 712 black top Endura, auto, bumper guards, am/fm rear speaker 44k miles

sixt9x33rs

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Re: M-21 lube leaking out of the speedo cable
« Reply #14 on: August 25, 2009, 12:25:00 AM »
John do you have another part number for the seal? What I got today at NAPA was for an automatic transmission and they did not have the part number for the bullet.

Thanks!
'69 RS Z/28 Olympic Gold, 711
Flat hood no spoiler, black top, endura, 4:10
POP 39,000
69 X77 Z/28 69 711 Original Paint Unrestored
'69 X66 Convertible Cortez Silver 712 black top Endura, auto, bumper guards, am/fm rear speaker 44k miles