Aluminum 4 speed gearset conversion question

[Hyper_pak]

I picked up an OD front case and extension housing this weekend. I know the case is different from the cast iron, but my question is: can a regular cast iron gearset be swapped into the aluminum case without any special parts? I guess I am worried about the countershaft and the bearing retainer and front bearing. The front case only has the countershaft gear set, countershaft is missing. Any ideas? Thanks!

 

[1plydust]

I was wondering about that myself, as i found an a body 4 iron speed and 2 alum ones 4 sale, i heard it can be done but im not sure how, let me know if ya find out, thanks

 

[66fs]

OD cases have the 308 front bearing and bolt pattern. You can bolt any front bearing retainer except the small one for our cars. There were some early 307 front bearing OD's but I would not count on finding one. Gear sets interchange but you must change everything but synchros. They can have large or small rear splines also. I typically go the other way, swapping OD's into Iron cases so I can swap into std 4 speed bellhousings. That way I can go back if I want to...

 

[72bluNblu]

OD cases have the 308 front bearing and bolt pattern. You can bolt any front bearing retainer except the small one for our cars. There were some early 307 front bearing OD's but I would not count on finding one. Gear sets interchange but you must change everything but synchros. They can have large or small rear splines also. I typically go the other way, swapping OD's into Iron cases so I can swap into std 4 speed bellhousings. That way I can go back if I want to...

Yup, right on. You can switch gearsets from iron to aluminum or aluminum to iron, but you have to take everything.

Switching the OD parts into an iron case will also strengthen the OD compared to the aluminum case, you won't have to worry so much about wearing out the case around the bearings.

Switching regular 833 gears into an aluminum case would get you a lighter standard 833, but at the sacrifice of longevity compared to the iron case. It'd be stronger than an aluminum cased OD because of the way the shafts are loaded under power, but it wouldn't be as strong as an iron cased standard gear 833. Probably not an issue at all though, even the 833 OD aluminum case transmissions are decently strong, just fine for pretty much any street driving, even behind a big block.

 

[fzmax]

I put the standard internals in an OD case and that is in my car right now. Since I was using the OD bellhousing as well the bearing retainer fit just fine.

However, I had to still use the cast iron tail shaft. The OD trans has a the smaller output shaft. You can buy an aluminum tail shaft from Passon (I think they are ~$250), but if you're going to do that you might as well buy his aluminum case as well.

It's got no issue handling my 101 HP 170 slant, but over the winter there will be a little bump in power. I am hopeful that Passon's five speed will be out by then or I"ll have to consider a TKO or a T56 and hack up the floor.

 

[1plydust]

ok thanks, so i guess its not worth the weight savings, how much weight saved by going an alum 883? thanks

 

[needsaresto]

Bout 30 lb's..most of the weight is the gears themselves.