I hear allot about the M50D, But how do you know if your truck has the "ZF" 5-speed? What oil does it use?

 

The sure way to tell, is just look at the side of the trans. If the ribs on the side are in a diamond pattern, it's a ZF.

And ATF.

 

If you can hit 25-30 in 1st gear...its a M5OD

 

1st gear is only good for about 10 mph. At 10 mph tac is at about 3400 rpm. I have a 4.50ish gear ratio. I determind that by jacking the rear end up, painting a mark on the driveshaft, and seeing how many times the driveshaft rotates for one turn of the tire. It was 4 1/2. Whats weard is both back tires turn in the same direction, but it does not feel like the truck has a reaf locker driveing down the road.
BTW: MY 4" EXHAUST PARTS ARE HERE!!!!! I am going to put it on now. I'll make another post tonight and let you know how it sounds!