1986 Lincoln Town car with traction lok locking differential. One tire was in muddy water with the other on pavement with good traction. The tire in the dirt was spinning while the other one would not move, instead there was a loud grinding noise from behind the tire accompanied by some smoke whenever l even lightly pushed the gas pedal. Why did not the tire on pavement pull the car out of the muck (which it had sunk into along the whole right side of the car) or at least just spin the wheel that was on the pavement. l understand that the car was probably to stuck to pull itself out but is it normal for a locking differential to grind like this.How concerned should l be with the grinding and smoke that occured. The wheel bearings are all new and the drive system was just checked by a mechanic who said it was working properly. 122,000 miles on it and it seems to drive down the highway fine after this with an occasional rubbing sound at low speeds. Thanks
l notice that many people believe that the car does not have a locking differential. l have checked the Vin, original vehicle literature, and the dealership window sticker, the car does have the locking differential. Additionally, the car spins both wheels at the same time on ice further confirming this. l also wanted to clear up the smoke, the tire that had the smoke near it never actually spun, it could not move due to the weight of the car on it, l was able to watch it and the tire never moved an inch.The car does not have anti lock breaks (one suggested culprit). Thank you for your ideas, just wanted to further clarify the situation.

u chould of damanged it but not bad enought and the smoke was probley the tires

Sounds like you do not have posi-trac rear end.

Most town cars of that vintage did not come with trac loc as standard equipment, your VIN will verify if it actually has it. l would guess your grinding noise is coming from the anti-lock brake ''tone wheel'' located behind the rotor. If mud got in there it would not be a good thing but if you get it cleaned out in time you can probably get away with minimal damage. l doubt your grinding noise is coming from the trac-loc unit, if it was that would be a seriously SHOT rearend.

smoke from tire
noise from axle and spider gears!