Just picked up a gallon of Valvoline gear oil and a tube of Trans-X limited slip gear oil additive. Have a few questions about the process since I have never changed the fluid in a LS, just regular open differentials.

1. The rear end (Dana 70) takes 3.5 quarts correct?

2. The fluid should be ½ inch below the fill hole right?

3. How much of the Trans-X should I put in?

 

As I recall the mopar bottle used to say 7 percent. So 3 1/2 qts = 112 ounces. So 2 four ounce bottles should be about right.

 

The dana's require the fluid to be below the check hole by a 1/2". I check ths by putting my little finger in the hole to the first joint and tip it down. If I get fluid on my fingernail I know its close enough.

The trans x amount sounds about right. You have to drive it in tight figure 8's on pavement to see if you got enough in. It should try to bind up when doing this but should not bind during normal tight turning, like at a light or in a parking lot. More transX usually is not better than a little less.

Make sure the truck is sitting level side to side and check it a while after you add the fluid, its thick and can take a while to even out.