1991 Cadillac Deville transmission slip

Several different options, and all will have different costs. At the mileage, I would strongly consider replacement. An overhaul is difficult to estimate until you tear it down, if you need hard parts(planetaries, drums, sprags) the price can escalate quick. A replacement unit is more cut and dried. Figure the labor to be around 8-9 hours at shop rate, and the reman trans to be in the 1500 range. This is a guess, but a general idea.