The carrier in the OP's truck could be either a Tlok or a Plok....the cover must be pulled to verify which one it is. You can't state that it is only a Tlok.

There is lots of different price point D80 kits....so, you have to be very specific when quoting a price like that. Clearly, you can get a Koyo master kit for under $200. You can spend more if you like.

D80 bearing and install kits

I can't find any firm pricing on a Plok clutch kit other than in the area of $150.

Tracloc clutch kit is $221

D80 Tracloc is $595

35 spline Trutrac is $581

If it is indeed a Tlok, I'm not at all surprised that it is loose at 150K....that is normal. A plok can go well beyond that since it uses variable clutch preloading that runs the clutches loose when not required and loads them much more than a fixed preload LSD (like a Tlok) when traction is required.