schmegeggie

If I were to say, pick up an M22 trans and swap it out with my M20, what kind of issues will I have?
None? Easy swap?
Anybody been down this road?

ED69ray

I went M-21 to M-20 to TKO600

The only issues would be la 1st gear change from 2.52 to 2.20 and possible clutch disc replacement. Early M-20 is 10 spline and I believe all the M-22's are 26 spline.

Personally I' would not bother - go with a 5 speed

Grumpy 427

Grab the m22 and smile get rid of that m20 lol good upgrade

TheSkunkWorks

FWIW, my own choice would be to put that Italian M22 wide-ratio gearset and HD mid-plate in my M20, as that 2.20:1 first doesn't best suit my engine/FDR combo. However, I may just save up for the Richmond OD 5-speed I really want...

Secret Squirrel

If you have your eye on a particular one, check the length. I believe pre '71 boxes are 1" shorter,

Belgian1979vette

There are the same dimensions. Check for bearing wear and rear end ratio. With an M22 you should at least have 3.73 in the back to get good 1st performance. Good tranny, i have one, sadly it is not with a 5th...

ZZ71S

http://www.5speeds.com/book.html
Have you seen these guys I am thinking about geting one of there m22 w

TheSkunkWorks

IIRC that's where I first saw that M22 wide-ratio gearset among other bits I want. Paul is a CF member and has published one of the best transmission books out there with lots of Muncie coverage.

Solid LT1

M22 can be had in either 26spline or 10 spline input shaft. You also need to consider if your putting it into a pre 71 Vette with a small 27 spline (THM350 style) output shaft/yoke or a 71 and later with a larger 32 spline (THM400 style) output shaft/yoke.

There are several options besides the original close ratio gearset now avalible in the M22 helix, that is the only thing I miss from the TKO600 conversion, the gear whine (I'm a strange guy.)

Belgian1979vette

I understand what you are saying. I would like to see this option, plus the long 1st and the gearspread of the M21-M22 in the tko also. Makes using the rapid acceleration of the 4.11 make more sense

Remember that part of the strenght of the M22 was the gearspread (and thus long 1st)

LeapinLizard

When I replaced the clutch and serviced the transmission, I identified it as best I could as an M20, the "wide ratio" one. The M21 and M22 are considered "close ratio", as far as I can tell. I really think you'll find the swap to be one of the easiest things you can do under your car. IFF it's only a trans swap!!! The usual caveats, of course: match spline counts carefully and make sure the new gearbox is sound before you pay for it!!! But once you're sure you have the right part, the swap itself is TOO easy!

As for driving...

I don't mean to hijack this thread, but could you elaborate on that point?

It's my understanding that the M22 (aka "Rock Crusher") is considered a "close ratio" transmission. In a typical large displacement engine, the power band is somewhat generous, IMNERHO. It seems to me that a wide power band would work best with a wide gear ratio.

I only say that because our Lizard makes something over 3000 RPM at slow-lane cruising speeds, with soccer moms passing us, staring. OTOH, "the other car", which has a "wide ratio four speed automatic", makes just over 2000 RPM at fastest-of-the-fast-lane speed. The Autodyne RPM Calculator program corroborates this within reason.

Maybe it's the diff, which is something like three and a quarter (mark on the drive shaft, SWMBO making one tire rev, me counting chalk marks passing by) "ish". I'm not sure what the T-bird's diff has, but I don't think Corvette options get much lower numerically.

We get a reasonable speed around parking lots, which tells me the (low * diff * tires) formula is tolerable (could be higher, could be lower), but I'd think that a lower RPM at 60MPH would make for a higher MPH at redline...

And if we're stuck with a 1:1 top gear, wouldn't that mean a very tall (low number) rear gear with a very low 1st and evenly spaced 2nd and 3rd on the way to that 1:1 4th?

Maybe you're drag racing your sports car... I like velocity and cornering (both ways) and mileage at speed... The only way I would put an M22 in any car of mine would be with the modern "wide ratio" gearset. Unless I was racing and those ratios happened to fit the track.

That's what I think, anyway, but I'm certainly no expert! All I know is, I personally have driven a lot of 3, 4, and 5 (and more) speed transmissions, and this car wants a fifth and maybe even a sixth gear! Or MUCH wider steps between the four we do have! To get up to much more interesting speeds, that is, which the car can easily handle. And to converse with a passenger on a weekend cruise...

YM(as always)MV...

Solid LT1

Autogear imports the M-22 gearsets in the original 2.20:1 first gear, a 2.56:1 (M-22W gearset) first gear or the new 2.98:1 first gear (M-22Z gearset.) The 1.43 3rd gear in a M-22Z gearset would be a challenge for a 300HP motor but, a good running big block wouldn't even notice the large gap to the 1:1 fourth gear of a M-22Z gearbox.

Someone made a good point that the wider the difference in tooth count of a gearset effects strength but the 22.5 degree helix of a M-22 is about twice as strong as the 45degree helix of a M22/21 Muncie gearbox.

There is also an ULTRA CLOSE ratio 2:1 first M-22 gear set from auto gear but, this is best left to a dedicated track car and not a street car.

Here is a link to Autogear for contact information:

http://autogear.net/muncieproducts.htm

ED69ray

Take a look at the TKO600RR

I just installed one in my "69 sb car. Its ratios are:

2.87 1st, 1.89 2nd, 1.28 3rd, 1.00 4th, .82 5th

Its got a nice tight 5th gear that should work well with my built sb and I won't have to run 80mph to use OD.

With a 255/50x17 rear tire and 3:73 rear I show 71 mph at 2700rpm as opposed to 58 mph with the 4 speed

If I was running a big block with tons of low end I'd prob have opted for the taller .64 OD but with a 10.25-1 sb I don't plan on spending much time cruising below 2200 rpm

No way in hell I'd drop $2K+ on a tranny for a street car and be stuck with a 1:1 final

Belgian1979vette

The bigger the "steps" in between gears the more punch they take from the drop in RPM if you don't let of the gas, like one does in racing and hard driving.

The second important thing about the typical gearspread of the short ratio trans was to keep the engine in its powerband. Now, this is a thing that can be completly different from one engine to another. An M22 is a trans that needs to be combined with a 4.11 rear to get a good 1st launch. This will keep your engine working above the 2500 rpm mark at all normal driving speeds in every gear. Since it is in its powerband at that point, it makes accelerating a lot easier. Thus it also will be faster around corners.

The problem is at high rpm. If the engine falls short on top, you could run out of breath on longer stretches, and the others will catch up.

So bottom line : its all about the combination you are building.

The engine i'm using has a power band from 3000-7500 so it is all there...