I'm looking at converting my Bronco to an automatic. The good old 435 is going to need a clutch soon and i'd really rather just put an automatic in it. I prefer stick over auto myself but this 435 is like driving a grain truck in the city, it's no fun.

So... What auto should I look for, what issues will I run into (obviously shifter issues) and the biggie, can I keep my current transfer case? I don't know my gear ratio, can you pull that from the VIN? It's low, I can tell you that.

 

Have you thought about swapping in a 5 speed? You'd have to swap in a hydraulic clutch and pedals, but you'd have to swap in pedals for the auto anyway, and probably have more fab work involved when it comes to moving the cross member, different length drive shafts, etc.

Your gear ratio is possibly on a tag on the rear differential. There's no guarantee that the original gears are going to be in there (unless you know the full 32 year history of your truck) so you can't rely on the VIN.

Another method is to jack up the rear of the truck and count the revolutions of the drive shaft to revolutions of the tire, but I can't remember the specifics as there's a few "extra" things to consider when doing that method. Someone may know the details.

 

The thought has crossed my mind. Especially since I have a fresh M5R2 sitting in my garage. That transmission has such a terrible reputation but I never had any problems with it in my '90 F250. We hauled trailers full of cows all the time and ran that truck to 180k with no problems. The reverse gear is perfect for a plow truck but 3x too fast for everything else. Other than that I loved that transmission.

It would be a big step backwards for off roading but it would be so much better in town.

Would my T-case work with it?

 

I think a lot of the reputation comes from them burning up. They had seals that would leak and then you'd run out of fluid. Replace those with brass and it solves the problem. I've never heard of one actually breaking. The only other complaint I hear is reverse.

I don't think you'd have much of a difference off-road either way. With either the M5 or the auto, you won't have a crawler/granny gear anymore.

As far as I know, there's no differences between fitment on any transfer case.

 

the ZF would provide a granny low for offroad use. tend to be pulletproof like the np435.