Interior and Upholstery Odometer kinda works

[Thev6stang415]

So I bought my mustang a month and the odometer did not work (something the guy didn’t mention to me) but I figured it was the gears since it’s a common problem and I still had the Speedo working. So I bought the gears and replaced them (the old ones were shot and like clay) but when I drove the car it worked for a split second then stopped again? I hit the dash and it spun 3 tenths of a mile then stopped. I took it all apart and it was fine I even spun the gears by hand and it had no problems but the second it’s together it won’t spin properly. P. S. Neither the odometer or trip odometer work until I hit the dash then they work but stop again