Tranny issues

[J-440]

 Have a 727 that I rebuilt.  Reverse is fine but when I shift to D, the wheels won't turn.  I have to apply the gas for them to do so.  Did this with the car on jackstands.  Going to check the linkage but but just wondering if anyone else had this problem.  Thanks again.

[Kern Dog]

I am really glad for your sake that TRANNY ISSUES refers to transmissions.

[J-440]

 Ba Dump Bump... He's here all week folks!! Thought I was doing Caitlyn Jenner eh?? Nah my tranny is way manlier.

[John_Kunkel]

Was everything OK before the rebuild? Could be a rear brake problem.

[J-440]

 Forgot to mention that the wheels spin in neutral as well.

[John_Kunkel]

On jackstands, the rear wheels will spin in Neutral due to the "windmill" effect of the tight clearance on the clutches. If applying the brakes to stop the rear wheels results in the engine bogging down, there is an excessive  drag problem.

If  linkage adjustment isn't the source of the original problem, there's probably some cross leakage causing the trans to be in two gears at once. Were any valve body mods made during the rebuild?

[J-440]

 I get the wheels to spin in N and D but I have to step on the gas, and then they keep spinning, I hit the brake, they stop, and I have to step on the gas again to get them to spin.  I rebuilt the trans using a step by step performance guide.  Both clutch packs are new as well as kevlar bands, seals, snap rings, a new valve body (non reverse), as well as a Gear Vendors OD unit. I also noticed that each clutch pack is a different thickness so I didn't get those confused.
  I'm just looking for advice for now as I won't have a chance to work on the car till Sunday.