Help. Gotta 81 F150, 351M, C6, NP205, 4x4. Bought for cheap and was not running. Fixed it but now it really slams hard when changing from park to reverse or drive. Also has a delay going into drive when cold. Hope it's something external to the case cause I don't wanna go back in.

Thanks.

 

Have you changed the vaccume modulator. Might try that, they're pretty cheap. These symptoms realy have no adverse effects on the drivetrain, just annoying to some people.

Nathan

 

If you park on any kind of incline, then the little bar inside the transmission that serves as park is under a little stress (the weight of the vehicle). I have a '90 F150 351 E4OD that does the same thing when I put Park under a load. If you stop, keep the brake pedal down, and apply the parking brake before putting the transmission into park, then it should relieve the stress.