Why did GM do this???

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Matt69olds

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With the constant battle the bean counters and engineers are fighting, I’m really curious why the engineers were victorious with this argument!

On my son’s 92 Yukon, the transmission crossmember is held in place by bolts that are twice as long as needed, with spacers on top of the crossmember to take up the clearance. I have taken enough of these trucks apart over the years to know it’s not some backyard hack, GM really did this.

On a subject a little closer to “home”, I have taken apart lots of truck th400 cores with big heavy spacers (about the same size as thimbles of sewing thread) on the bolts that hold the transmission mount to the extension housing.

I have little doubt shorter bolts were already in GMs parts inventory. And even if those spacers cost a penny per truck to install, multiple that penny by a few million trucks and that penny quickly adds up to real money. So why did GM use them???
 

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legopnuematic

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Short bolts don't stretch the same as long bolts do, so long bolts+ spacers allows proper clamping load

I see prairie drifter beat me too it.
 

Edelbrock

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With the constant battle the bean counters and engineers are fighting, I’m really curious why the engineers were victorious with this argument!

On my son’s 92 Yukon, the transmission crossmember is held in place by bolts that are twice as long as needed, with spacers on top of the crossmember to take up the clearance. I have taken enough of these trucks apart over the years to know it’s not some backyard hack, GM really did this.

On a subject a little closer to “home”, I have taken apart lots of truck th400 cores with big heavy spacers (about the same size as thimbles of sewing thread) on the bolts that hold the transmission mount to the extension housing.

I have little doubt shorter bolts were already in GMs parts inventory. And even if those spacers cost a penny per truck to install, multiple that penny by a few million trucks and that penny quickly adds up to real money. So why did GM use them???


One situation I have seen where hardware / bolts don't make sense has to do with car model versions. Same for the wiring harnesses. Let say you have 1 million cars made. 200,000 LT models, 200,000 LS and 600,000 LTZ models. Hiring a company to make 3 different wiring harnesses is more expensive than just making all the harnesses that will accommodate everything on the most decked out model and then just dismiss the extra wiring plugs on the base model. For example, your car might have a fuse spot that is not used, and having wiring connectors where fog lights would go, but there are not fog lights, and they just put a plastic plug plate over the fog light switch location on the dash. So longer bolts might accommodate a different trans, or skid plate, or what ever. Assembly line is streamlined to the max. If there was a cheaper way to do it, they would. And logistics is everything when it comes to large scale production, war, or what ever else. Billions are spent every year on logistics and planning for these types of things, and it generally all comes down to "what is cheaper" on a massive scale.

Plastic dip sticks, plastic intake manifolds, thinner glass, robotic assemblers, outsourcing, and so on.
 
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