Project "Might as Well Make it Right While I'm at It!"

[Yukon Jack]

This is going to be wordy so hang in there!

As some of you may recall, my Rockwell T221 transfer case in my 69 K20 got low on gear oil and took out the input bearings on the rear of the case back in March of this year.



I considered my options of repairing or putting in a spare Rockwell or putting in an NP205. As luck would have it, a while back I bought a 1984 1 ton crew cab parts truck for its front axle so I had on hand a good NP205 with adapter for an SM465. And yes, part of this overall project will include swapping in the Dana 60! Say good bye to the drum braked closed knuckle Dana 44!!!

Now initially I was bummed when the Rockwell went belly up, but in the end this is a good thing! My last major project was swapping out the 69's mighty 307 SBC for a 454 BBC from a 1989 1 Ton. As some of the seasoned members will remember, I ran into terrible firewall clearance issues - in my opinion, worse than normal. That swap project turned into the proverbial “Might as Well” project and before I knew it I had the whole truck completely disassembled and rust repairs were tackled along with a new coat of paint.

My research had told me that a 2" body lift was usually sufficient to get around BBC fitment issues. I, of course, was not smart enough to do a test fit of the cab on the frame before sending it out to get painted. Well, we got the cab all painted and when it came time to put the cab on the frame there was major firewall clearance issues! Mind you the truck was at the body shop and in the interest of time it was decided to clearance the firewall to make the BBC fit.

Even after modifying the firewall, I still had issues which required the use of more body lift than I am comfortable with.

This is where the present Rockwell problem turns out to be a good thing. I’ve decided to put in the NP205 as it just seems like the logical thing to do - newer transfer case with no parts availability problems. Well, in researching the swap I have discovered the NP205 setup with adapter is 5" longer than the Rockwell T221 setup with adapter. The location where the adapters bolt to the crossmember is 2" different. That is going to be a very good thing as that will allow me to move the BBC forward 2" which should allow me to remove my excessive body lift and reduce it down to hopefully just a 1" body lift. I believe I will be able to leave my transfer case crossmember in its current location and only have to move the engine crossmember.

In case anyone cares, here are two pics of the different transfer cases with detailed measurements. Some of these measurements were done with the Rockwell installed so if I find any inaccuracies, I will update this info.





This shows the Rockwell + adapter overall length is 14" while the NP205 + adapter overall length is 19 ½"

For anyone doing a T221 to NP205 swap, it appears the NP205's crossmember sits about 1" lower so I’m not sure if I will need to lower my crossmember or if I will be okay since I’m still going to have a slight body lift. It may be I will need to lower the transfer case to keep the engine angle/driveline angle happy.