Tell me about the Rockwell transfer case in my sons 68

[57NAPCO]

I’ve never owned one and know nothing about em. I am familiar with 203’s and 205’s. One of my boys is doing a total restoration on his 68 K10 short Stepside. It will basically be a new truck when he’s finished.

Thanks for any input

[franken]

The internet knows stuff.
https://www.google.com/search?q=rockwell+transfer+case

[MJN]

Should be a T-221, Heres a link to the parts catalog you can download.

https://www.cummins.com/components/d...ture-on-demand

https://graphicvillage.org/meritor/PB90172.pdf

[68isgreat]

I had a Rockwell mated to the original 6 cyl/4 sp on my 68 k10 step, but I wanted something I could run on the freeway at comfortable rpms, so I ditched it and went with a newer 1991 350 tbi/700r4/241c passenger drop combo. From what I understand, Rockwells are stout, but have straight gears, are whiny, and parts are hard to come by and expensive also. Probably fine for a low speed 6 cyl restoration I suppose. Mind also had a factory pto winch installed, with the pto attaching to a plate on the side of the transfer case.

Clean truck btw! Much nicer than mine was.

[57NAPCO]

Thanks y’all

[cbeerman]

I have some info, lists, and a few parts. The 67 -69 T221s are married units, so they bolt to the transmission via an adapter and there is a 10 splined coupler similar to a 205 that connects the output shaft of the trans to the input shaft of the transfer case. The rear bearing of the input shaft has a aluminum cover that can crack if the bearing goes. There are a coupe of guys on the 4x4 tech sub-forum that are very knowledgeable about them. What trans is the T221 connected to?

[Chaparralman1974]

Originally Posted by 68isgreat

I had a Rockwell mated to the original 6 cyl/4 sp on my 68 k10 step, but I wanted something I could run on the freeway at comfortable rpms, so I ditched it and went with a newer 1991 350 tbi/700r4/241c passenger drop combo. From what I understand, Rockwells are stout, but have straight gears, are whiny, and parts are hard to come by and expensive also. Probably fine for a low speed 6 cyl restoration I suppose. Mind also had a factory pto winch installed, with the pto attaching to a plate on the side of the transfer case.

Clean truck btw! Much nicer than mine was.

Do you per chance still have the transfercase mounted PTO for the Rockwell?

Thanks, Clay

[Chaparralman1974]

You will find that the Rockwell T221 is a good solid transfercase that, in my opinion anyway, adds to the nostalgia of these trucks. They are noisy!! It will whine going down the road, but that is part of the fun in owning these trucks.

The rebuild of the T221 is fairly straight forward. Check out my build thread as I went through and completely rebuilt mine. The bearings are all still available, and there are options for the oil seals as well. The harder (more expensive) things to get are the shafts, gears, and shims. Torque King is your best resource for parts, but they can be pricey.

If you decide to tear into it, make sure that you take know of the shims under the bearing caps as you will want to keep the same shim thickness for the rebuild.

Also worth noting is that the mating sleeve from the output shaft of the transmission to the input shaft of the transfer case will likely be worn. It was a bad design to begin with and since it gets zero lubrication during operation, they tended to fail over time. I made sure to coat the splines of the shafts liberally with sticky grease to help with wear over time. You will likely not want to use this transfer case for any serious off roading.....the NP205 is a MUCH better case with stronger parts availability, but if you want a good setup that sounds like an old Chevy should sound like then the Rockwell will suit you just fine.

I was lucky enough to score a NOS T221 last year....It had been sitting in a warehouse since the early 70's. It was pretty neat to crack it open just to see the machine marks on all of the gears.


Cheers,
Clay

[68isgreat]

Originally Posted by Chaparralman1974

Do you per chance still have the transfercase mounted PTO for the Rockwell?

Thanks, Clay

Sorry, no.

['68OrangeSunshine]

I have a core SM465/T221 lash up in my spares. Might go in a project '72 K/5 with a 292, or into a '67 K/10 Suburban if I decide to go back to manual. PO converted a V8 [283?] T221[?] truck to 454/TH350/NP205. Big block is shot.