Having problem shifting into second gear when cold. After it warmed up it was fine so while repairing a minor leak in the rear end, the dealership changed gear lube in differential and transmission. Put Royal Purple in both and now the shifting problem has gotten worse. Really stiff when it's cold but then, before it gets warm, it will want to go into second gear really quick and it scratches gears going in. After it warms up completely it shifts perfectly and have no problem downshifting into second either. Anybody have any ideas?