Removing TM on a 6L80E - helpful, hurtful or hard to say? (the answers are inside)
Consider this a Public Service Announcement if you will, but for those of you driving your 6L80-equipped car hard but still have at least some TM enabled you're actually hurting your transmission rather than protecting it. (I know this is likely to start a heated debate and/or big controversy so I'm more than open to any and all opposing viewpoints on the subject)
Contrary to what most people believe, TM is there for the purpose of having the transmission shift smoothly, not to protect it. Under normal, part-throttle driving conditions it's fine if you leave some (or all) of it in but if you regularly run the car balls-out (i.e. at the dragstrip like I do about 300 times a year) you'll kill the trans much faster that way as compared to turning it all off.
The reason being is that there are roughly 30 or so clutch disks in the 6L80 and TM actually introduces slippage in order to achieve the smoother shifting which works great around town but not so much at full throttle. To illustrate this using a manual transmission as an example, think about how long your clutch would last at the track if instead of shifting it hard and fast you slipped it into each gear.
As for a more relevant example we can use my car - I'm running a built transmission from Century using the new Alto clutch disks and I've made 157 low 10 second passes on it since September 2010 and it's still shifting perfectly every time. Granted it is a built transmission with more durable clutches but the same rules also apply to stock transmissions.
I set up a friend's 2007 Corvette (with almost 70K miles on it) around two years ago and despite making over 300 passes while running high 10's/low 11's (depending on the DA) it shifts perfectly 99% of the time and shows absolutely no signs of any problems whatsoever. For the 1% of the time where it has acted up it's always after he got a REALLY good launch. This sort of goes against the grain with respect to traction issues on the 6L80 as it's usually a case of the more traction the better.
So there you have it, let the debate begin I guess. :D
Christopher