I am beggining to belive something is wrong with my Eaton Posi. Whenever I am driving alone and floor it from a dead stop, I spin like crazy. While I am spinning my truck will start sliding to one side or another and I have to let go of the gas otherwise I will loose control of it. The weird thing is that i does leave to even tire marks on the pavement. Now when there is another person in my truck, its a different story. I will spin very little and it just goes. What freaks me out even more is that friends with the G80 have more traction than me. They easily hook up even when they are riding alone in their truck.
I was planning on changing the differential oil and just adding very little friction addative maybe that will help my situation. What lubricant do you all recommend for the Eaton posi. Any comments or suggestons will appreciated.

 

The sliding to the side is the weight difference from side to side, that is why when you have your friend with you, you don't do that, even weight distrubution. You actually want about 2 tubes of friction modifier in your diff when running the Eaton, it even stats so for GM applications in the direction sheet in that came in the box. I also recommend using a heavier oil in the rear, and stay away from synthetics with a limited slip. Great for wear, but sometimes messes with the friction plates a bit, too damn slippery. I use a heavy *** 85 to 140 oil in mine. Until I got my traction bars, I spinned a lot also. You got a short cab, short bed like me too. Also do you have a stepside? If you do, then you weight 150lbs lighter than a steel fleetside truck, just in the back where the weight will help traction. Your freinds, do they have extra cabs that weight more, do you have more performance mods? You have tuning, and if they don't you will be able to more quickly apply power to your rear wheels. I actually got better 60' times when I was stock, but I run faster now with my mods. That was cause the truck had just the right amount of power to floor it off the line, and it would just go. Now if I do the same it will spin the tires, and get bad wheel hop. That is why on the street I carry 80lbs of sandbags tied in the rear, and have Caltracs!

These things have helped me reattain my traction, and with the Eaton, I have more control in all driving conditions. Once I put the traction bars on, mine no longer kicked to the side, it would just chirp the tires and go straight.

 

Your posi is working.You can't fishtail if both rear tires are not spinning.How much air pressure do you run in your rear tires?I have good results with 28# passenger side,30# drivers side rear.you may be making more power than me.Goodluck,Jim

 

hodgeee, I have a stepside and mostof my friends have reg cab trucks that are mostly stock except for one(rgvsierra) and he has better traction.

 

My Z71 did that same thing .. I knew it was locked, but it would go side to side.

Try counter steering a little bit to see if that helps.