4 speed cast iron case

[madmopar]

Has any one ever swapped out the guts out of a aluminum o/d into an iron case? Does it have to be iron o/d case or can it be any large bearing iron case?

 

[Shorthorse]

http://www.brewersperformance.com/

 

[jimt1971rr]

I had an iron case o/d unit with a 4.8 bearing retainer. Sold it last fall but worked just fine.

 

[dpstark2]

I've done it. I put late OD guts into an early A-body iron case. You have to use the correct bearing for the input shaft for that case (small- some might think this a bad idea, but it worked OK). Using a small bearing case also make assembly a bit of a pain. There is also some interference in the little stand inside that supports the reverse idle gear shaft that has to be ground away (should be fine too). Just keep your gear sets together or be very careful to match them up with good used gears. You can't mix OD and non-OD reverse gear parts, for example, for some reason...

 

[moper]

I've done it too. It makes the reassembly order of operations a little different because of the gear placement but it can be done. Of course, the reason the OD has a larger front bearing is not just the gear size. There's a lot more stress on the input bearing because you're running through the cluster gear in 4th rather than just "straight through" the mainshaft. So I'd call it a short term fix rather than a long term plan.

 

[dpstark2]

Mine was destined for a /6 so I wasn't super concerned about the bearing. I figured it was worth a shot, as the aluminum case was worn out and clearly would cause issues soon.

The nose of the output shaft and the receiving portion on the input shaft are larger on the OD transmissions. I'm certain the input bearing takes more load than a non-OD unit too, but I have to think the union between the input and output shafts will also take a lot more load and that's why they are bigger. Which would give out first? I can't say.

Passon makes his Hemi OD to fit the large bearing case. I've helped assemble two of these, so it seems like the large bearing should be fine for most applications, and I would do that if possible.