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Transmissions and Rear Ends Three on the tree or four in the floor? Shift it all here.

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  #11  
Old December 23rd, 2016, 07:13 PM
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Default Re: SM420 speedometer

Quote:
Originally Posted by James View Post
How many teeth on your gear? I have a small selection.
Hello,

This would be awesome but as of today, I still can't remove it, I can't find a deep socket. I tried 22mm but to small and 24mm too big....

What is it in inch? 15/16"


I made a lot of researches and I remember having read that for a 4.11 rear end ratio, it was a 12 tooth.

What do you have and how much you want for?
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  #12  
Old December 23rd, 2016, 10:33 PM
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Default Re: SM420 speedometer

Quote:
Originally Posted by Sponge View Post
Hello,

This would be awesome but as of today, I still can't remove it, I can't find a deep socket. I tried 22mm but to small and 24mm too big....

What is it in inch? 15/16"


I made a lot of researches and I remember having read that for a 4.11 rear end ratio, it was a 12 tooth.

What do you have and how much you want for?
Yes it is 15/16". However a 24 mm deep broach socket will fit, I tried it and it fit on the spare unit I have. The only problem you might have is the socket outside diameter might be too big and it is hitting on the case. If this is what happening you will need to grind on the socket to clear the transmission.

In my truck it did have a 4.10:1 rear axle and the speedometer gear I pulled out had 11 teeth with 3 teeth on the gear inside the transmission.
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  #13  
Old December 24th, 2016, 09:51 AM
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Default Re: SM420 speedometer

OK, I need to see what I can do.

What do you have in stock?
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  #14  
Old December 24th, 2016, 12:24 PM
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Default Re: SM420 speedometer

I have an 18 and an 11 tooth as well as the matching gear (7 an 3 respectively) that goes inside the transmission.
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  #15  
Old December 24th, 2016, 09:41 PM
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Default Re: SM420 speedometer

I just removed my speedo cable and tried my 24 mm deep broach 6 point impact socket on my transmission. It fit and there was no room to spare.
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  #16  
Old December 24th, 2016, 10:04 PM
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Default Re: SM420 speedometer

So I used a 15/16" socket and I could remove it.
Surprinsigly, my gear is not damaged, 13 tooth and it moves freely.

I'm now wondering if the cable inside the speedometer cable housing is long enough to fully engage into the driven gear.

It needs to be deep in the driven gear by something like 0.7mm and ideally 1cm inside.

Is your driven gear also round then only kind of square inside?
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  #17  
Old December 25th, 2016, 12:12 AM
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Default Re: SM420 speedometer

Kind of hard to tell in my picture. It is round on the outside and .1" square on the inside.
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  #18  
Old December 25th, 2016, 11:43 AM
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Default Re: SM420 speedometer

If you think the inner cable too short it might be the nut on the back of the dash not tighten all the way. This would allow the inner cable to be short on the transmission end. Reach behind the dash and make sure the nut on the housing is tight and the cable housing does not move.
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  #19  
Old December 25th, 2016, 03:50 PM
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Default Re: SM420 speedometer

It was tight but i was thinking loosen it a bit to give more room in the transmission.

I'll try a bench test.


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  #20  
Old December 26th, 2016, 08:49 PM
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Default Re: SM420 speedometer

Found my issue... The driven gear is no longer square inside... I remove the cable and did a bench test... It is round deep inside and the cable is not driven... I need to find a way to get the cable stuck inside....

If anyone has a 13 tooth, it would be great.
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