62 gmc k20

[jwsteffen@gmail.com]

Hey all- I'm a noob here. I just picked up a 62 K20 and it came with two Trans/TC combos (the original is an SM420 with a t221 m7 that is seized up). I'm working on getting things spinning in that again, but in the meantime, I'd like to make sure I know what I'm dealing with and what my options are. The Second combo appears to be an SM465/t221 N? Attachments are not working for some reason, but the trans has a 3901127 on it.

Anybody have any arguments against just using the 465 combo? The input shaft is different-- anything else I'll need to change out?

Thanks in advance for your help!
Jason

[Captainfab]

Welcome to the forum

If you change to a SM465 you will need to change the bellhousing to a '68+ bellhousing to accommodate the larger 5.125" diameter front bearing retainer. Personally I would go with a NP205 transfer case instead of the T221.

[jwsteffen@gmail.com]

Thanks for the info Captain. I've seen several people say the 205 is superior, but why exactly? Just curious. I'm sure parts availability, but what else? Since I already have two 221s on hand, I just have to weigh the benefits you know.

Thanks again

[Captainfab]

The NP205 is stronger and a bit quieter, plus parts availability. Most 205's are a married type transfer case. You should be able to pick up a complete SM465/NP205 combo from a '73+ truck. But like I said, that is a personal preference.

[jwsteffen@gmail.com]

great thx

[Short 3/4]

Just want to throw out another opinion here:
Both cases are cast iron gear drive, so if treated right you probably won't break either one.As far as parts go, while the 205 is more common, Torque-King has most of the stuff you should need to keep a 221 going. They can also help you with parts for your closed knuckle front end. The 205 is quieter, but unless you plan on lots of high speed freeway driving not going to make a lot of difference ( and make sure you don't let the gear lube get low). I also like the 221 shift pattern better
I like a divorced case because it's a lot easier to drop the trans or xfer separate ( that 205/465 is heavy and awkward) You can even slap in a 2wd drive shaft and drive your truck while working on the case.
I prefer the SM420 because first gear is lower and the position of reverse is better for rocking out of a hole
I also just like to keep my junk as original as I can because I think the old stuff is cool. Once changed its hard to go back.
Bottom line this is a personal question with no right answer, just do what makes you happy
Good luck with your project Tom

[jwsteffen@gmail.com]

Appreciate the new info!

[Peanutbutter]

the 465 and 205 is twice as dependable and much quieter, its a no brainer unless you are trying to keep it original, but that's just me.