vette68 said:
Why is it that my 37 year old Corvette with a Muncie M21 has absolutely zero driveline slack, but my '05 GTO has driveline slack after 4000 miles? I hear it especially when pushing in the clutch after allowing the engine to brake the car. It's so annoying. I've had people in my brand new car ask me what that noise was. I'm real glad to hear it's "normal" and the dealer won't do anything about it. What a crock of SHlT.
Sad to say but here's what the reason for the clunk really is!
It starts with the clutch being almost 12" in dia. then working its way back into the gearbox which has 6 count, them forward speeds and a reverse speed gear all are rotating mass's, when you shift gears you are changing the speed of all of these components that ride on needle bearing (unlike your 37 year old M21).
Then you add the increased center distance of the transmission itself and the extra face width of the gears for the added strength and you have a much higher degree of what we call reflected inerta.
It then transfers back down the driveline and the sound enters the car through the rear axle mountings. (AKA junk in the trunk.)
We as transmission engineers (I was one with GM) spent millions of $$$$$ trying to reduce driveline clunk and the the only way to do this is to drive around it, or produce smaller cars with less power and skinny tires with more flexable sidewalls and smaller rotating components.
By the way your 37 year old corvette has a sliding reverse speed gear thats non synchroized so you really only have 3 speed gears and a smakk rev idler in the clunk path on a 85mm center distance and gears with less then 25mm face width that would never take the torque put to ground with todays tires and engines.
And it screams compared to todays transmissions in gear noise in all gears except 4th and thats only because its directly hooked to the output shaft!
If you think this is BS then upgrade your engine to todays 400 hp 400 lbft of torque and use our new engine management system and add a set of 275X40X18 tires to rear and go do 10, 1/4 mile pass's I'd be real suprised if you make 5 without blowing the clutch or the transmission unless you have a pretty tall rear gear 3.73 or higher!
NO we don't make em like we used to............
