SOme years ago, Detroit Diesel (GM) was falling on it's azz. Trying to compete with CAT and CUMMINS, plus Mercedes and MAN (all 4 strokes) with a 2 stroke was not making it. It was so bad you needed to have someone really piss you off before you got in to drive one. Penske bought Detroit from GM, turned it around, introduced a full electronic controlled 4 stroke that didn't leak oil everywhere and got competitive. The 60 Series was a nearly instant hit. Good manners, pull like a draft horse, and good fuel mileage. Then they (DDC) developed the 50 Series 4 cylinder, setup a propane conversion for that diesel, and off to the races again.
FWIW: Allison Transmission is part of Detroit Diesel Corp.
My thought is that if Penske bought, or is buying Saturn from GM, he HAS a plan.