That's funny, I have never had anybody say they saw anything on a slip going to aluminum. Always hear people saw zip. For years.
And I have heard of guys hurting aluminum driveshafts. One such guy is the guy who bought my old car.
Just like rollerized trannies. Spent all the money on one years ago, saw nothing.
Maybe not in a street car. Guys from 2 different 4.70 groups near me both have told me they have picked up going to aluminum. I didn't ask them, they told me outright. If you hurt an aluminum driveshaft, maybe you shouldn't have bought it at Walmart.
