Howdy all, I am new here, and I have a question about transfer cases and a swap. I have a 1974 Chevy Custom Deluxe 5/8 ton, 6 lug axles. This had a 350 cid and now has a 454. It has a T350 trans, original, and then it has a second trans followed by the transfer case. All are married. The interesting thing is, I have four settings on the shifter, High and low ( this stays in two wheel drive), and then I have High lock and low lock ( 4wheel drive ) and do I love this too. I have no clue what kind of transfer case it has. Judging by the size, I would guess it is gear driven or one heck of a chain. At the bottom where the front drive line comes out is about 8 to 10 inches wide. I have not found any numbers on it or even a name brand. It has custom drive shafts in it. I bought it this way a few years ago. Now for the other part. I have a 1984 Chevy Suburban K20. This has a 700R4 trans in it and married to a NP208 transfer case and 4:10 gears factory. What I would like to know, will the secondary trans and transfer case in the 74 fit on my 700R4 in the suburban. How hard is it to do this? I do know most of the parts I have to buy for the 74 is 3/4 ton parts. Any info you all could give me is very appreciated. Or even if someone knows what the transfer case in the 74 is. Thank yall very much.  

It sounds like you have a NP203 transfer case that maybe someone has put in a part time conversion kit.  Do you have lock out hubs on the front axle?  The shift pattern (Hi-lock,Hi,N,Low,Low-lock) is the NP203 full time transfer case.  So this secondary transmission you have, is it an underdrive or overdrive?  Both the TH350 and 700R4 have a 27 spline output shaft, but I do believe that they extend out the rear at different lengths.  There is no factory adaptor to bolt the two together but it can be done.  I think the best answer would come from Offroad Design.  Go to there web site (offroaddesign.com) and get the phone number and call them.  I don't feel right posting there number on here.  

It goes t350, secondary trans ( I am not forsure if it is an over/under drive, it does have a window for a PTO on it ) then the transfer case. I have never seen something like this. if it is an over drive it sucks....I get 6 mile a gallon, loaded or full. However, I can run a hundred and twenty and not be wide open. Yes I do have selecto hubs on it. I do know it was all time 4x4 in 1974, stickers still on visor, but is not now unless it is in lock.  

yeah sounds like it has to be an under/over drive unit. i'm not sure why you wanna do the swap, is something wrong with unit on the i think you said burb?  

I think that the external reduction unit that is a normal part of a NP203 (between Tcase main body and tranny) is being mistaken for a aux tranny.  

SnoMan:
I think that the external reduction unit that is a normal part of a NP203 (between Tcase main body and tranny) is being mistaken for a aux tranny.

LOL, that makes complete sense after he finally stated that it has the plate covering where to put a PTO.  You do not have an auxillary transmission, that is just part of the NP203.  

Knowledge is a beautiful thing! I have been asking transmission shops what kind of transfer case it is snce I bought it, as well as any person with a four wheeling rig I could find and nobody could seem to tell me. I do thank yall very much. I hate to say it but the lodgic behind me wanting to change it out is, please dont laugh, The 203 is hudge and I have done some pretty amazing stuff with that 74 and never thought twice about it, espically with that 500 hp 454 in front of it. Then I bought this 84 burb k20 this year and saw this itty bitty np208 and thought, oh boy, this will break the first time I need to tow with it out in the field or at the ranch in Ar. This was the only reason I wanted to change it out. Now that I have found this forum I will ask and search for knowledge. I thank yall very much.  

Don't be affraid of the NP208 in your 84 Suburban, just change the fluid and run it.  If it does break at some time, then deside if you put in another NP208 or change it to some other case.