203 np or 205 or 208

[speedd67]

I have a 78 gmc w/203np that I bought. Someone put manual locking hubs in and when i engage the four-wheel drive it makes really bad noises. checked hubs,u joints,and gears in front and all are fine. I believe that they changed it over to one ton cause when i needed rear break parts for e-brake that was what i had to use cause the 3/4 was different. I think it may be the chain in the transfercase. But i was wondering if i should go with the 205 part time or another 203 or change it to a 208 because that is for one ton. I need help because i don't know enough about four wheel drive to know the difference and not enough shops around to help me . Please help if some knows the difference.

[mike reeh]

well heres the lowdown, in short version..

the 203 is a common, cheap, cast iron transfer case. Its a GOOD case even though it has a bad rep because the front wheels are driven off a chain (which wears and will tend to give you problems after about a billion miles which they all have)... It would be the easiest to replace, and undoubtedly the cheapest.

the 208 in MY opinion isnt an option. Its off later model trucks (started sometime in the 80's) and its aluminum and has a slip yoke. and would just be a real PITA to swap in, it wouldnt be a direct swap by any means. get this one out of your head. plus its not that strong like the 203 or 205.

now if you can find someone with a 205 and the correct adapter for your transmission (probably a th350? possibly th400) then go for it. this is the baddest of the bad of xfer cases for our trucks and is bulletproof. its very similar to the 203 but its part time and is all gear driven. its also cast iron. very strong, much lighter than the 203, etc. This is your best choice in the long run. It will also increase the value of the truck beleive it or not. The np205 is very desireable and you will probably pay a pretty penny for it if you can find a good one. They are out there though, there was about a billion np203/205s made. Oh, you'll have to modify your driveshafts. That can get pricey too

hope that helps a little

dont hesitate on going with a np203. But I recommend having the part time conversion kit installed. this will give you a true part time 4WD transfer case. then you'l have 2 low, 4 low, and 2 hi & 4 hi...

good luck

mike

[76vandura]

I know this thread is a little old, but what is this part time conversion kit and where do I buy this? Also, how do I tell if I have one already? Thanks a lot!!

[9teen69]

Looking at buying a 77 cheyenne blazer 4x4 with 350 trans and 350 motor. How do I identify the transfer cases?

[bpmcgee]

9teen,

Do a search on google, I found it pretty easily when I was looking last time, but I don't recall the difference.

Brian

[Lester]

The NP205 is the better unit, no doubt. But only slightly when you compare the cost to the benefit, when swapping out a 203 for a 205.

Also, don't bother with the part time kit, its not worth the cost or the effort. They cost about $300 if you can still find them and it will take you about 4 hours on a Saturday to swap this out if you have done it before and all weekend you have never had a transfer case open before. Its is doable it just takes time.

The benefits are supposed to be less wear on the drive train and your tires and better gas mileage and performance. I have no idea how you could ever measure the reduced tire wear or the increases in mpg or performance relative to making this change.

I know I will never waste my time and money doing one of these swaps again nor will I waste my time swapping 203's for 205's again. The results just are not there.

What I would do without hesitation is swap a cheap working 203 for a damaged one any time I had a problem.... they are cheap, easy to find and will probably bolt right in where yours is now without too many issues.

Lester