Bad news for the holidays - differential going bad. This is a two-wheel drive '96 with 176k miles on it and in my opinion shouldn't have crapped out. I've pulled boats, hauled mulch, crushed brick and rock with it and it's always been a great truck. Question for you mechanics - repair shop says they can put a USED differential in it for $1200. Is that about the right price? Should I put it in, then sell the truck because it's now somehow compromised, or fix it and keep on driving? My preference is to keep the truck until the wheels fall off (it's paid for), but it seems to me that when something like this happens, another major problem is just waiting in the wings.