Have an 89 f 350 7.3L 4x4. Trans is pretty much junk. Would a zf 547 be a direct drop in for a zf 542? Figured I would have a bit better trans, and give me a wider range to choose from.

 

as long as it came off a diesel. gas and diesel transmissions have different cases and bellhousing bolt patterns.

 

Actually, big block and diesel ZF's have the same case, they're just drilled different.
Small blocks are indeed completely different, though.

Used this pic and the adapter off my 6.9 to get a late model ZF onto my old oilburner.

 

Good to know, I think I have a line on a '97 4x4 with a 7.3 in it. Is there much to taking the trans out? I can get them to flip the donor vehicle over for me at the junkyard for easy access.

 

Anyone know where to find a used ZF 5 or a cheap quality rebuilt one? I went and looked at the donor vehicle, everything was correct, except it turned out to be an automatic.

 

Mission impossible. Gonna have to go the rebuilt route. We've called 15 local junkyards, and they've searched for used one's. None to be found.