M21 vs T10 - Page 2

Keith Tedford · #11 03-23-2010, 08:27 PM

I was told that our was out of a '79 Z/28 and had the 2.64-1 first gear. It was the same length as the M20 we took out and we used the same driveshaft when putting the car back together.

396L35 · #12 03-23-2010, 08:47 PM

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those are good with like a 3;73 gear, I think there 2;88 first gear??

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Hopefully a 2:88 gear but I've seen them with a 3:42. Now you have to see if its a 904 steal case.

396L35 · #13 03-23-2010, 08:49 PM

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What ratio is your Super T10?

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Can I find out from the outside?

It's from an 80 Z28 allegedly, if that's a clue.

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How many rings/groves are on the input shaft?

**Fast67VelleN2O** · #14 03-23-2010, 08:53 PM

It looks like it has 6 rings on the input shaft. Should be a 3.42 first gear.

x Baldwin Motion · #15 03-23-2010, 10:03 PM

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.......... Now you have to see if its a 904 steel case.

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This is one of the HEAVIEST transmissions I've ever carried (but it's been a while)

It seems to have rusted up almost overnight

x Baldwin Motion · #16 03-23-2010, 11:33 PM

Is this T10 a mutant, with the alum tail and the steel case?

Trans-man says T10 two inches longer at the case; ear to tail case end. The gears are out of the M21; could the length variable be the size of the rear spline ?

**Fast67VelleN2O** · #17 03-23-2010, 11:40 PM

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Is this T10 a mutant, with the alum tail and the steel case?

Trans-man says T10 two inches longer at the case; ear to tail case end. The gears are out of the M21; could the length variable be the size of the rear spline ?

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I just measured a Muncie and a Super T10. There is a 1/2" difference in length from mounting flange to the rear seal. Your Super T10 is not a bastard. A lot of those transmissions came with iron case and aluminum tail shafts. I have owned bout 30 of them over the years.

-Matt

x Baldwin Motion · #18 03-23-2010, 11:46 PM

Thanks Matt, can I get away with my original driveshaft with the 1/2" difference?

Blade4444 · #19 03-24-2010, 12:55 AM

According to the info i found, 6 grooves mean it has a 2.88 first gear, mine has 6 and i really hope is not a 3.42.
this is the ratios i found,
Number of ID Groves, 1st 2nd 3rd 4th
2, 2.43 1.61 1.23 1.00

3, 2.64 1.75 1.33 1.00

5, 3.42 2.28 1.46 1.00

6, 2.88 1.91 1.33 1.00

**Fast67VelleN2O** · #20 03-24-2010, 01:03 AM

Your number 5 and 6 are backwards Blade.

Chris- I think you could get away with your standard driveshaft.

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