Does anyone know if RPO code NW9 traction control is another term for posi or is traction control totally something else? The junk yard parts guy says traction control is the new term for posi on 4th gen cars.

 

No.

Traction control uses the brakes (via the ABS function specifically) to control wheel spin. If it senses a wheel spinnin, it applies taht brake.

 

thats what i was figuring, but i guess i just need someone smarter than me to verify that. also now i can tell the parts guy he is an idiot

 

Also, if it has traction control, it's almost 99% guranteed to have a posi.
To ID a trac enabled rear end it will have no sensor or hole in the top of the pumpkin and if it has the brake backing plates, there will be a sensor in each one as well as a reluctor ring on the axle right behind the axle flange.

 

I wouldn't bother with all the "telling" and "idiot" business.... you never know, if the guy doesn't hate your guts for making a fool out of him, he might have a stupid moment someday that will work in your favor. It's never a good idea to just go around pissing people off with a superior attitude.