What's the best way to test your Dana 70 limited slip to see if it is working right?

 

On sandy ground hook a load to the truck and see if you spin both the wheels when you take off.
If it's getting worn or you have'nt used the additive, it will probably only spin the pass. side wheel.

 

Sorry i should have been a little more specific. I'm trying to find out if the rear end is going bad. It locks up fine, but when I take off from a stop sign slowly and make a turn it shutters. So I don't know if it's the tranny or rear end. It also seems to roar on the highway even if I slip it in to neutral.

 

maybe whoever serviced it last didnt put the friction modifier, thats exactly what they do without it. it probably feels like the rear end is gonna jump out from under the truck. hopefully the clutches arent too far gone and you can get it to function properly again with a correct fluid change( with the additive)

 

Thanks, I just got the same advice today. What ratio friction mod/fluid should I run? What type of gear oil have you guys liked best? It just started jumping the last few days so it's parked until I drain and fill.

 

I changed the fluid today and it works perfect now. I used about 8 pints of "limited slip gl5" and 8oz. of friction mod. No more jolting and shaking on take off. On the inside of the inspection cover there was a glob of what looked like anti seize that trapped any shavings. Nobody at the parts house could tell me what it was. Either way I could'nt be happier. From now on every 25,000 it's getting changed!