The old Ford/Mercomatic seems pretty durable on my 52 as its original and never had any work done that I know of. Yes, the kickdown rod is important. If its working I'd leave it alone. I think mine needs adjustment as it has a real hard low to drive if I upshift manually. Works fine in drive though so rather than making it worse by adjusting blindly I'll just leave it as is.This is only the second yr for that transmission, and yes he linkage is critical. Newc