Swapping a Np203 for a Np 205 Question?

I have a question on swapping np 203 to np 205 transfer case? ok i have a 1977 Silverado 10 Chevrolet 4x4 all time with the np203 in it and i would like to swap it for a np205 what do i need to get for adapters and parts or what will i need. Im not sure whether i have the th 400 or 350 transmission but its one of the 2 i think its a 350  transmission its pretty much all stock stuff. And so i was thinking of putting in lockout hubs and the np 205 thanks for all help!! And one other thing is the np 208 pretty much just like the np 205?  

i belive ther is an adapter plate becuz the older 205s have a different bolt pattern i had the same exact setup in my 74 but i just swapped in a muncie 4 speed  

I have a question also, I have a 96 chevy 4x4 1/2 ton w/350 motor, will a turbo 350 transmission mate up to the transfer case?  

rhock22:
I have a question also, I have a 96 chevy 4x4 1/2 ton w/350 motor, will a turbo 350 transmission mate up to the transfer case?

Why in the world would you do something so silly? If tranny failed because of big tires and stock gears you need to fix the axle gears not retro to a older tranny with a much taller first gear. (BTW, if you drove the 4L60 in the "3" position and lock out OD rather than in drive/OD you would have in effect a THM350 with a deeper first gear and deeper second too. I see so many people wanting to retro to older slower trannies rather than properly gearing axles in trucks.  

My tranny went out of 96 truck, I don't have the money to replace with exact tranny, but I can get a turbo 350.  This is just a work truck, will the splines line up?  

to answer your transfer case question...yes there is an adapter to mate the np 205 to a 350 or 400 tranny...they r not the same adapter though...you need to know what tranny you r using and what the spline count of the transfer case is also...it is a bit more then just finding a part and swapping them....
first question is why do you want to go to the 205??..i see alot of people wanting to do this, i thought there for a while that i was going to do it also but i think i can spend $$$ somewhere else instead...if you think that the 205 is stronger, i agree..but i don't know that i really need it....the 205 is not like the 208... the 205 is gear drivin, no chain to run the front driveshaft, which means it is alot harder to wear out the 205 internals...the 208 is a chain drivin transfer case, just like the 203..but the 208 has a lower low then the 203...the nice thing about the 203 is it has a low 2wd, so i can put it in 2lo not worry about locking in the hubs and i can have more power off road...no i have a detroit locker in my 14bolt so i can still get around alot of places...not going to try to hill climb or anything but if i need to pull into my favorite bunny hunting site 2lo allows me to have more power without getting out of the truck to lock in the hubs....if there is one thing i learned about swapping parts on my truck it is to make sure you do research on both the pros and cons of anything you want to do...so many people will do the popular choice instead of the practical one just because it sound cool or, the next door guy did it...don't waste your money  

rhock22:
My tranny went out of 96 truck, I don't have the money to replace with exact tranny, but I can get a turbo 350.  This is just a work truck, will the splines line up?

You will have constant ECM service engine lights because it will be looking for tranny which is controlled by ECM. YOu would be time and money ahead to find a bone yard 4L60e to swap into it. Look for a mid to late 90's unit. They started cheapening them up after that and did not fix this new problem (cost cutter parts) until 2005.  

I'd have to go with Sno on this you're going to have to find a replacement 4L60e from a junker. The th350 is not going to give you any mechanical problems if you swap it. The problem is going to be electical and computer problems. Have you tried to see if your 4L60e can be rebuilt?  
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If it was a 92 or earlier, it would be a 700R4 which is not electronically controlled by ECM.(a 4L60e is just a 700R4 with a elctronic/ECM control)  

in my opinion tha 203 sucks! u cant put it in 2 wheel drive its a full time 4 wheel case and everytime i wanted to get two wheel on the road i had to drop the front shaft the 205 is alot better yea u gotta get out an lock the hubs to get 4 wheel but that beats tha hell out of dropping the shaft everytime  

rebel_wheeler707:
in my opinion tha 203 sucks! u cant put it in 2 wheel drive its a full time 4 wheel case and everytime i wanted to get two wheel on the road i had to drop the front shaft the 205 is alot better yea u gotta get out an lock the hubs to get 4 wheel but that beats tha hell out of dropping the shaft everytime

Have you ever lived with a fulltime 4x4 truck? I have for over 20 years and while it is not the best thing for cross country trips it rules in overall city/urban and off road driving plus you can safely use low range anytime on hard pavement. BTW, if you buy a Doadge or Jeep made in last 6 year it is kinda in 4wd all the time anyway because none of them can disengage front drive axle from wheels. They drop Tcase feed but wheels still spin up diff and drive shaft and use power and add a little wear.  

yea i know they are better for driving but i like ta dump tha clutch aroun corners in my truck its my hot rod-off road truck.  

You can get some excellent hole shots with fulltime 4x4 even on less the optimum surfaces too. I can spoil you. Far better than conventional 4x4 for driving on slick surfaces as you have better average traction (no slippage induced by torque bind) and better directional control. I plowed snow for many years with a 4x4 with it and rarely even needed to lock Tcase.  

A freind of mine has a late 70's model Dodge Power Wagon with full time 4x4. it's a pretty sweet set-up. Like Sno say's you don't want to do cross country road trips with it, but running around town and up and down these mountain roads it's awesome. Don't even get me started on the off-road performance.  
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I like this topic. It has alot of information. Let me just mention about the 203 part-time boat anchor tcases I have had in two Chevy trucks. One was a 75 1/2 ton 4x4 with 298,000 miles on it when I bought it! The thing was shot. The 350 motor had a bad cam so I put a new one in and a week later it spun a main bearing. In goes a 305 out of an 85 Chev truck a guy swapped out for a 350. Anyway, I got it all running good and thought it would be fun to go racin around town on a Friday night. It sure was! I would put it in 2-LO at a light and take off and have my buddy hit the thing in 2 or 4-HI when I told him to after I hit neutral when I was topped out; this gave me higher gears. So in reality I had a 6 speed 350 trans I smoked alot of Camaros and even a Mustang with a small blown 5.0! I am surprised the tcase ever held up to that abuse.
Now for the other truck, a 79 Chev 4x4 1/2T SB 454/TH350/203. Part-time kit also, I had 3.73s 35s, 10Bolt front, 10.5 14Bolt rear and the tcase was put through the same test. It held up too! I tried everything to get it to stretch the chain or break in any way at all to no avail. So why is this tcase such junk?