M21 vs T10
 

my M21 is still in the VerySlow Transmission Shop, I have inherited a T10 from a later Camaro. I have a fat fine spline yoke to change on my driveshaft, but are the cross member mounting locations and the length of these transmissions the same?

as always, thanks in advance for the smarts https://www.yenko.net/ubbthreads/imag...ns/worship.gif

https://www.yenko.net/ubbthreads/imag...ouguysrock.gif

Re: M21 vs T10
 

It's been a few years but I swapped out an M20 for a Super T10 in our'72 Lemans Sport. It had the factory Hurst shifter. As I remember it was a straight across swap with minor bending of one shift rod. Everything else bolted right up. I think the slots in one set of shift arms are longer than the other so you can switch one way but not the other. The ST10 worked just fine.

Re: M21 vs T10
 

Now the M21 needs a new case. I am told the T10 bolts up but is two inches longer in the tail section. Need a shorter driveshaft now if I want to use the T10 (which he says is tough and like new inside).


https://www.yenko.net/ubbthreads/imag...s/confused.gif

Used driveshaft and have it cut, or measure and try to find the correct size? anyone have suggestions?


thanks.

Re: M21 vs T10
 

Nothing wrong with using the T10 and you can get some low 1st gears. Mark

Re: M21 vs T10
 

[ QUOTE ]
Now the M21 needs a new case. I am told the T10 bolts up but is two inches longer in the tail section. Need a shorter driveshaft now if I want to use the T10 (which he says is tough and like new inside).

https://www.yenko.net/ubbthreads/imag...s/confused.gif

Used driveshaft and have it cut, or measure and try to find the correct size? anyone have suggestions?

thanks.

[/ QUOTE ]

Time to get out your yard stick. I've never seen a T-10 that was a different length than a M20/21 (except for the odd Pontiac Muncies) so don't take anyones word for it. Otherwise, you'll cut your driveshaft three times and find that it's still too short. https://www.yenko.net/ubbthreads/imag...emlins/eek.gif

Re: M21 vs T10
 

They are the same length. You won't need to shorten your driveshaft. What ratio is your Super T10?

Re: M21 vs T10
 

How about sell your T-10 to fund the Mucie project?

Re: M21 vs T10
 

[ QUOTE ]
What ratio is your Super T10?

[/ QUOTE ]

Can I find out from the outside? https://www.yenko.net/ubbthreads/imag...lins/dunno.gif It's from an 80 Z28 allegedly, if that's a clue.

http://hphotos-snc3.fbcdn.net/hs479...._1745502_n.jpg


http://photos-f.ak.fbcdn.net/hphotos..._4100865_n.jpg

Re: M21 vs T10
 

http://photos-d.ak.fbcdn.net/hphotos..._6545375_n.jpg

Re: M21 vs T10
 

those are good with like a 3;73 gear, I think there 2;88 first gear?? https://www.yenko.net/ubbthreads/imag...ins/3gears.gif

Re: M21 vs T10
 

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.

Re: M21 vs T10
 

[ QUOTE ]
those are good with like a 3;73 gear, I think there 2;88 first gear?? https://www.yenko.net/ubbthreads/imag...ins/3gears.gif

[/ QUOTE ]
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.

Re: M21 vs T10
 

[ QUOTE ]
[ QUOTE ]
What ratio is your Super T10?

[/ QUOTE ]

Can I find out from the outside? https://www.yenko.net/ubbthreads/imag...lins/dunno.gif It's from an 80 Z28 allegedly, if that's a clue.

http://hphotos-snc3.fbcdn.net/hs479...._1745502_n.jpg


http://photos-f.ak.fbcdn.net/hphotos..._4100865_n.jpg

[/ QUOTE ]
How many rings/groves are on the input shaft?

Re: M21 vs T10
 

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

Re: M21 vs T10
 

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

[/ QUOTE ]

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
http://photos-d.ak.fbcdn.net/hphotos..._8338292_n.jpg https://www.yenko.net/ubbthreads/imag...lins/dunno.gif

Re: M21 vs T10
 

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 ?

https://www.yenko.net/ubbthreads/imag...lins/dunno.gif

Re: M21 vs T10
 

[ QUOTE ]
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 ?

https://www.yenko.net/ubbthreads/imag...lins/dunno.gif

[/ QUOTE ]

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

Re: M21 vs T10
 

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

Re: M21 vs T10
 

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

Re: M21 vs T10
 

Your number 5 and 6 are backwards Blade.

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

Re: M21 vs T10
 

Here is a good info site for the ST10

http://fiedlerh.home.att.net/BW.htm

Re: M21 vs T10
 

Sorry I couldn't see the pictures on my work computer. It looks like a nice 904 steel case with a 342 1st gear. You can get away with 373's or 410's with a taller tire and still have some low end out of the box. These trannys are extremely strong with the steel case and mid plate and it would be the one I would use instead of the M21. Mark

Re: M21 vs T10
 

Thanks everyone for all the help. https://www.yenko.net/ubbthreads/imag...lins/beers.gif https://www.yenko.net/ubbthreads/imag...s/headbang.gif

https://www.yenko.net/ubbthreads/imag...ouguysrock.gif

I will install the T10 in the Chevelle and save the M21 for the Nova conversion next winter. https://www.yenko.net/ubbthreads/imag...iggthumpup.gif



Now, about that peg leg 3:08 10 bolt I have. What's the best unit for swapping the guts for a 3:73 posi ? https://www.yenko.net/ubbthreads/imag...ns/shocked.gif

Re: M21 vs T10
 

see if someone is sitting on a old real GM posi, I would check in with Eric 69L72RS he has tons of posi's.

B.

Re: M21 vs T10
 

You have a 3.42Z ST-10, with or without the 904 steel case this trans is rated at 285 ft/tq...
What makes these weak is the input gear has 17 teeth and the mating gear on the cluster has 31 teeth... M-21 has 26T input/27T cluster...
I buy these all the time with blown input and cluster gear to get the good main case...
Your final drive in first gear with the 4.10's would be 14.022, good for 20ft before you have to shift...
The early Muncie's are 21 1/4" long, the ST-10"s are 22" long, so you might need a drive shaft shortened...
You might want to rethink what your going to do...
E-mail me if you want to talk about it... Crash
[email protected]

Re: M21 vs T10
 

I have a BE coded 12 bolt with 5:13's if you are looking https://www.yenko.net/ubbthreads/imag...lins/smile.gif

I also have a nice 4 series carrier if you locate a housing.

As for the M21 & T-10. My buddy just did this swap on his 1972 Nova and he did in fact have to shorten the driveshaft.

Re: M21 vs T10
 

Yes, the difference between the(my) M21 and the T10 is 1 3/16" (your actual measurements may vary) and requires a driveshaft trimming. Also requires the fatter yoke installed at the front end of the shaft. So, I will now be holding the T10 and waiting for the M21 guts to be put in the new case. https://www.yenko.net/ubbthreads/imag...lins/frown.gif

(at least the Nova is finally on the road!) https://www.yenko.net/ubbthreads/imag...lins/smile.gif

Re: M21 vs T10
 

Picked up M21 with "Italian" guts this afternoon. We'll be putting Olive Oil inside. https://www.yenko.net/ubbthreads/imag...mlins/wink.gif



https://www.yenko.net/ubbthreads/imag...iggthumpup.gif http://hphotos-snc3.fbcdn.net/hs414...._8377971_n.jpg

Re: M21 vs T10
 

For Racing I'd recommend ATF. It can take the heat. Olive oil will "cook down" to a sticky slime. https://www.yenko.net/ubbthreads/imag...iggthumpup.gif