Planning on atleast 500hp and 500lbs of torque. Will either of them hold?

 

T56 should be fine. Upgrade to a steel 3-4 fork though. If you get a used box I'd completely rebuild and blueprint it just to be safe.

The leMans race Vipers are running a modified version of the T56 dubbed the TR-6R. They use dog and slider synchros, not very streetable, and a oil pump and cooler to keep trans temps down, but otherwise the trans has a lot of stock T56 parts in it. These cars are pushing upwards of 750HP and just as much torque.

 

Nice, thanks for the info

 

The T10 was behind some of the most powerful muscle cars ever made, like the LS6 Chevelles and 427 Corvettes.

Just something to think about.

 

and today.. the T56 is behind some of the most powerful muscle cars evermade, like the LS6 and 427 Corvettes.




btw, old school LS-6... new school LS6.

 

Haha, never thought of the irony of what I said, lol

 

Engine torque has nothing to do with the 3-4 fork. Abusive shifting does. Frankly, with the girth of the stock 3-4 fork, I have zero plans to upgrade mine, because they don't bend. The synchronizers have issues when abused, but the forks do not bend.

But I bet Tremec is thrilled they sell a lot of forks that aren't needed in rebuilds.

 

I don't think there were any T10 application 427 Corvettes ever made.

The LS6 Chevelles had Muncies.

Regardless, I'd take a 1982 Z28 super T-10 over an M21 or M22 any day. Stronger case, parts are easily purchased.

 

AT $50 a steel 3/4 fork is cheap insurance. That's the way I looked at it. Steel is stronger than aluminum and it takes all of about 20 minutes to do the swap. Maybe the stock fork would be fine, but I wasn't going to risk it. Funny thing is that I had to hunt mine down. All the big T56 parts dealers were out of them because Tremec had recalled them all for the '03 Cobra production run. Oh did that ever **** me off. I finally found one through a list of dealers on the Tremec site. They are easy to come by now though.

The T-10 was used in the Shelby Cobra and a lot of early 60s ultra high performance cars. All GM cars that got the LS6 or 427 used a Muncie M22 for the most part during the late 60s and early 70s.

 

yes abusive shifting does it... but when you buy a used box, and are rebuilding it, you might as well spend the $45 while the box is apart and replace it.

so like you started to say, yes the DO bend.... but mostly when abused.

you get jackasses who dont realize that "hey, if it doesnt want to go into the next gear, theres a problem"... thoes are the dorks that just yank on it hard, thinking thats how you bang from gear to gear.

 

That's just slang. "LS6" is correct for both the old big block and the newer engine.

It's a RPO code. RPOs have never had dashes in them; or slashes either for that matter, even though Camaros with RPO Z28 were badged "Z/28" in the early 70s.

 

I thought the Muncie 4 speeds (M20-21-22) were basically T10 guts in a GM case?

In the late '70s, Camaros had ST10 trannys, but still carried the M21 RPO, even though muncies hadn't been used since '74 or so.

 

No; the Muncie and T-10 were 2 completely different things, even though they were rather similar inside. In fact, they're almost exacty the same, except that they're completely different. Very few parts interchange even though they are very difficult to tell apart just looking at them.

The Muncie came out in about 61, with a 15/16" countershaft. It was built (or at least designed) at the GM plant at Muncie (duh) where they make mostly heavy truck transmissions. They came with a 1-1/16" clutch gear with 10 splines, and the same output yoke and spline as the Powerglide. Those were pretty weak... better by far than the old Chevrolet 3-speed of the day (the one with 2nd & 3rd only synchronized) but still couldn't take alot of power. Then in about 65 or 66 they upped the countershaft size to 1" (.996" actually), which actually was a significant improvement. Seems like they also went from 90-some odd rollers on it to 112. Then in the late 60s, I don't recall the year, they came out with the M-22, which had the 1-1/8" 26-spline clutch and the same output size as the Turbo 400.

Borg-Warner came out with the T-10 in the early 70s IIRC. GM dropped the Muncie in 74, and after that, all GM 4-speeds for performance were T-10s. There were 2 models of T-10, much like the later Muncie; one with the 10-spline clutch and T-350/Glide output, and one with the 26-spline and T-400 sizes. That one was called the "Super" T-10.

Through the late 70s, GM used the "Super" T-10 in Trans Ams and Z28s.

The RPO (M21 or whatever) that's used at the assembly plant isn't necessarily the same thing as the transmission model. They were often similar but it's not a very consistent thing. Auto transmissions carry "M" RPOs too; M35 and M40 were used in alot of years back then for the 350 and 400 respectively.

 

I'll put it this way: If cost isn't an issue and I have a choice of one or the other, I'd replace the synchronizer assy. every single time instead of the fork. Food for thought.

"For the most part" to mean greater than 50%?

Nonsense. M22's are NOT anywhere near as common as people would like to think. Lots and Lots of M21's are out there that people think are M22's.

 

I didn't start to say that.

I'd like to see a bent one. Worn shift rail hole? Maybe. Bent? Haven't seen one yet, don't expect to see any.


That's how you get an LS1 into the next gear when the clutch isn't releasing. (sarcasm) Darn throwout bearing and restricted hydraulics.

 

you can drill the stock hyd cyl... or you can get the adjustible Mcleod one...

 

Yeah, every single one through 2002 REQUIRES the drill mod to work properly; I've drill modded a few cars. The McLeod doesn't bleed for a damn in my experience.

 

The M22 became available in very limited production only in Corvettes in 1965. These are actually modified M21s with the casting numbers ground off and new ones hand stamped. Documentation has been obtained to prove that these cars exist.

Starting in 1966 the M22 became an option on high performance cars. The M20 (wide ratio) and M21 (close ratio, like an M22, but has weaker gears) were also options. Almost anyone who knew what they were doing when ordering one of these cars new opted for the M22, because these cars were intended for drag racing or other forms of racing. That being said, on the whole M22s are fairly uncommon, especially today. One of the main reasons is that they weren't as strong as everyone thought. Also, it's easy to see why there are so few M22s compared to M20s and M21s, when you consider the production numbers of SS396 Novas, SS454 Chevelles, and 427 L88 Corvettes compared to other more common models of the same car.

Externally the Muncies all look identical. You need to decipher the main case casting number to verify and M22. When driving a car the M21 and M22 have the exact same gear ratios, so it's impossible to tell, unless you know the telltale whine of the M22.

Muncies are rare on the whole anymore, especially the M22. You may find them at swap meets in great numbers, but most are junk, requiring hundreds in new parts to be made serviceable. Good rebuilt ones are companding a hefty premium. I sold a prefect M21 for $750 plus shipping on eBay about six months ago. M22s in similar condition are well over $1,000 if you can even find one. Parts for them, particularly OEM gears, are getting very hard to find too.

 

Ok, I see now... thanks RB and TKO

 

Muncies are rare on the whole anymore, especially the M22. You may find them at swap meets in great numbers, but most are junk, requiring hundreds in new parts to be made serviceable. Good rebuilt ones are companding a hefty premium. I sold a prefect M21 for $750 plus shipping on eBay about six months ago. M22s in similar condition are well over $1,000 if you can even find one. Parts for them, particularly OEM gears, are getting very hard to find too. [/B][/QUOTE] Couldn't agree more dude! That's why I've ratholed several extra ones over the years and got them sitting safely in my storage shed. I also agree that if you know what you're listening to, it's damn hard to mistake the sound of the M-22 with the straighter cut gears, hence the nickname "rockcrusher".