Hi all. In older cars/trucks it was always just fill the diff until it pours out the fill hole. Well now I just happen to come across conflicting information when I was verifying the oil type. It sounds like the rear gets filled until the oil comes out, but the front is suppose to be stopped 5/8" before the top. That just seemed odd to me. I went back and looked in the service manual and oddly found that it only says to "fill" it. So is this confirmed that the front should not be filled up to the top? I have a 1500 with the 205MM HD Front Axle. Thanks.

 

Neither is really wrong. My rule of thumb for over 30 years has been to fill until I could stick my pinky in the hole to the end joint and feel fluid. I guess that's probably around your 5/8". An advantage of stopping there is you still have room to add a couple ounces of friction modifier if needed...

 

Oh geez I didn't even think of that. I'm pretty confident that my rear diff is open, not LSD. Is it possible the front is LSD an needs the additive?

 

LOL... no you don't need it up front. It's IFS, no chance of there being an LSD or locker there...

 

Man, thanks. You set my mind off on something I've never considered and wondering about the damage I've done over the years. Whew, ok panic averted.