this is an old thread, but for anyone having the same problem, it seems to me to be the kickdown cable causing the issue. if anyone one else has this problem, release the kickdown nuts and bring the cable close to the bonnet. this will relax the kickdown feature and then test drive, then slowly start tightening the top nut of the kickdown cable and test drive again, till you get the right change of gears. I know that I've had this problem on various cars, (Honda, ford, holdens) and this fixes them all. That's not to say that you might might not have any other problems, but since it was working fine before you messed with the engine, I'm very confident that it's the kickdown cable adjustment that's out of whack. Cheers, and good luck. I know it's an old thread, but this might help someone else with the same problem.