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Message: [QUOTE="Charles, post: 689475, member: 103"] See what happens to a motorcycle trans behind a 7.3 if you want to see that side of the spectrum. Then you can see all the broken hard parts you want. And there's the opposite end of the spectrum from the motorcycle trans. The only problem for you, is understanding that wanting either end is fine, it's only when you want one to hold gobs of torque AND still run syncro'd shifts that happen acceptably fast for a little pickup that you run into trouble. I've only stated this over and over. And people ask me why I say the same thing over and over, it's because it doesn't take hold. You don't know as much as you think you do it would seem. First off, the engine rotating assembly mass has nothing to do with a shift on a traditional manual like we're talking about here, a ZF6 for example. When you push the clutch pedal in you are no longer connected to the engine. It is the mass of the input shaft and the clutch disc that must be accelerated/decelerated until the speed matches that of the output shaft across the ratio you are trying to engage. And the weight of these components is SO important that a few hundred GRAMS change to the clutch disc can be felt on a shift! Go ahead and stack a couple full-faced iron discs on that input shaft if you think this weight is immaterial! You're clueless! The auto has no such restraint. It does not align anything, or match any speeds in order to change ratios. It simply applies the next ratio in succession. INSTANTLY. The instant you want the next shift it begins. The shift is completed as quickly as you can stand to have your driveline shocked. If you want, you can have it toss a driveshaft out from under the truck on a shift if you have a hard on for testing things. With the auto, shift speed is determined by how fast you WANT the shift to occur. The trans itself can physically complete the shift many times faster than you would ever want. As for parasitic loss, I'm not entirely sure the ZF6 is really that much better, if at all. I don't see massive swings in rear wheel power output between the two. I swapped from one to the other and noted nothing. Reason being, the ZF6 is pumping oil, so it has loss there, albeit not as much as the pump in the auto, but the really bad thing is that the ZF6 is spinning [b]6[/b] constant mesh ratios ALL THE TIME you're in gear with the clutch out. That's 12 gears constantly spinning on bearings and chewing on the oil. If it shocks you that they overheat, it shouldn't. At any given time there are 10 gears in constant mesh, burning on their bearings and shafts that are not being used for anything. That's a lot of bs swinging around doing NOTHING. Conversely, the auto uses the same basic planetary sets to produce all the ratios. How many gearsets are there in the 4R100 for gears 1 - 4? Are there 2? There's a lot of inefficiency in the manual box. Don't assume that it's a shaft in, shaft out. There's sh*t going in 12 different directions doing nothing but burning up fluid, making heat and wasting power. The trucks go down less often, go more places, burn less fuel, all while getting there faster with the auto. Sounds like the people picking the auto might have a more rational approach to trans selection than you. You can *** anything up. Most of the older allison trucks I've driven have too high a stall, and with mech pumps with a tight governor they have abrupt power rise and fall on and before shifts. In those cases, they just didn't have it right yet. Let me spec you a manual truck with too tall a rear R&P and let you melt through a few clutches trying to move around a jobsite, then you can bitch about a manual instead. Point being, you can get anything wrong. That doesn't mean that's how they all are. If you've ever watched a 6x6 oshcosh concrete truck buried halfway to the axles ease right on up a hill with 10 yrds on board you'd have to immediately get a grip on reality. A manual trans without miles of low gearing would do nothing but smoke the clutch and/or drop a shaft in so many situations like that. I literally see it DAILY. A guy can talk about how weak and girly the allison is all he wants WHILE being stuck in the driveway and getting pulled out by an allison tandem up the hill from him I've noticed. Idiots don't let things like that influence their life choices... LOL [/QUOTE]