Why Was The Muncie M22 Nicknamed The Rock Crusher, And What Were Its Weak Points?

Go bargain a winning lottery summons aliases quiet your status savings right now. Once you person your rate successful hand, acquisition a big-block GM musculus car made successful nan precocious '60s aliases early '70s pinch an M22 "Rock Crusher" four-speed manual. Yes, get nan M22 Rock Crusher, don't walk millions connected a 1969 ZL-1 427-powered Corvette pinch a sigh-inducing M40 automatic that's amended for resistance racing but worse for your soul. It'll beryllium cheaper to get, say, an L72 Corvette or an LS6 Chevelle, anyway. 

Now caput retired to your nearest agelong of quiet roadworthy and upwind done nan gears. Once you tin extremity yourself from giggling pinch glee, perceive to nan sounds nan car is feeding you. Yes, you'll perceive that awesome high-cube V8, but you'll besides perceive a stupendous magnitude of cogwheel whine. That's nan M22 earning its "Rock Crusher" name. 

M22s tin trace their lineage backmost to nan four-speed BorgWarner T-10, which itself evolved from nan three-speed T-85. When GM wanted stronger transmissions for its high-horse musculus machines successful nan early '60s, it tinkered pinch nan T-10's creation to create nan wide-ratio Muncie M20 and nan close-ratio M21. But arsenic torque figures increased, truthful did nan request for a stronger transmission. The M22 debuted successful 1965, designed to return nan tectonic-plate-folding torque of GM's astir powerful engines without becoming a pretzel, acknowledgment mostly to its straighter-cut gears, which are besides nan main root of nan whine. 

Still, moreover pinch their higher powerfulness handling, M22s person immoderate flaws. Aside from aggravated cogwheel whine, group constituent retired that nan M22's aluminum lawsuit tin flex, bend, aliases break, banal displacement linkages often hindrance erstwhile moving hard, and difficult shifts on original-equipment shifters tin moreover lead to surgery internals.

The M22's integrative shifter bushings deteriorate complete time, though alloy replacements will past acold longer. Gear spot isn't overmuch of an rumor pinch M22s unless you're going to push stupendous torque done a banal one. No, nan bigger — aliases possibly nan biggest — rumor pinch nan M22 is nan aluminum case. Aluminum, by its nature, stretches and bends much than alloy aliases iron. This intends that nan transmission's soul forces will push retired connected nan case, nan gears will move farther apart, and eventually, they tin break. Modern replacement Muncie SuperCases are thicker and usage a overmuch stronger 356T6 aluminum alloy to destruct this stretching.

Stock M22 shifters are mounted pinch a bracket to a crossmember. When nan transmission twists nether difficult acceleration, nan linkage tin bind, causing a missed shift. Upgrading to an aftermarket shifter, specified arsenic a Hurst, lets nan shifter equine straight to nan transmission, eliminating this problem. 

Another immense use of a Hurst shifter is its adjustable stops. As expertly demonstrated by Muncie transmission builder Paul Cangialosi connected his YouTube channel, GearBoxVideo, difficult shifts successful a Muncie pinch a banal shifter tin break nan combs that clasp nan forks successful place. But a Hurst's adjustable stops tin return this unit instead, preserving nan transmission's internals. It's almost for illustration Hurst, which helped create immoderate of nan astir desirable and outrageous musculus cars, from nan 455 Hurst/Olds to nan AMC Hurst SC/Rambler to nan wheelie-popping Hemi Under Glass Barracuda, knows a point aliases 2 astir performance. 

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Now that we've torn into nan M22's problems, let's springiness it owed praise. The 1970 LS6 454 whitethorn person been a terrifying monster pinch 500 lb-ft of SAE gross torque, but nan M22 was a much than formidable leash to reign it in. M20s and M21s besides recovered themselves coping pinch nan thrust of large blocks specified arsenic nan L72 427, but their gears were trim astatine astir 30 degrees, while M22s had higher people nickel alloy gears trim astatine 20 degrees to forestall shedding teeth for illustration a dentist-averse soft-drink addict.

Drag racers making dozens of consecutive runs surely admit those straighter gears, moreover if it tin make it sound for illustration there's a roots-blower operating beneath nan floorboard. Reducing cogwheel angles improves strength, but it besides increases noise. Case successful point, earlier "black tag" ZF six-speed transmissions successful nan 1989 done 1993 Corvettes had straighter gears and a 450 lb-ft torque rating. Later "blue tag" transmissions successful nan 1993-1996 Vettes person steeper cogwheel angles for reduced noise, but tin only grip 400 lb-ft. So if you don't for illustration cogwheel whine, possibly see a nice, inexpensive $13,500 1994 six-speed Chevy Corvette.

Case stretching and shifter issues aside, nan M22 was Hercules successful its time. If you're a purist who wants nan authentic acquisition of vintage muscle, do you attraction that nan M22 has immoderate flaws? Probably not. It whitethorn beryllium a relic of a bygone age, but what relic it is.