I know this has been beaten to death on many threads previously but I thought I'd pass on my experience. 34K miles on my '07 DC LB 4X4 w/LSD and I just changed out the fluid in the rear diff. Used Amsoil Severe Gear 75W-90 and added their Slip Lock LSD additive right off the bat. After hearing everybody's issues with synthetic lubricants, I thought it best to use the additive right from the get go. Long story short, not even a hint of chatter. Amsoil customer support suggested figure 8's in forward and reverse to work the additive into the clutches, although this didn't seem necessary in my case. Again, smooth and quiet right from the start.
Did have a thought. My Taco is the DoubleCab Longbed. With the additional 13 inches of wheelbase and the wider turning radius, I'm thinking that this configuration is probably less prone to LSD chatter than say a single cab or extended cab. Anybody have any thoughts on the subject?