Author Topic: NP203 conversion  (Read 5766 times)

Offline Willieb

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NP203 conversion
« on: January 01, 2015, 07:00:44 AM »
I've seen posts on this subject but I need more info. I have a 79' K10 short bed step side with a 350,Automatic with Np 203 case with auto locking hubs. I have a set of warn manual hubs to put on. what is in the kit and what is involved in installing a conversion it Thanx. Willie

Offline Jason S

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Re: NP203 conversion
« Reply #1 on: January 01, 2015, 09:29:14 AM »
You might add detail or clarify a bit. 

You said you have auto locking hubs - Is your NP203 currently full-time 4wd? 

Most of the kits to convert a NP203 to part time conversion would lock the spider gears in the differential on the back of the transfer case. The part time kit can be installed in the t-case without removing it from the truck.
http://www.summitracing.com/parts/MMK-501/

This should give you a pretty good idea of the part time conversion kit.
http://coloradok5.com/milemarkerpt.shtml
1973 GMC K2500, Super Custom, Camper Special, 350, TH350, NP203, 4.10's
1974 Chevrolet K10, Custom Deluxe, 350, SM465, NP203, 3.73's

"1) Peace through strength; 2) Trust but verify; 3) Beware of evil in the modern world"

Offline Willieb

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Re: NP203 conversion
« Reply #2 on: January 01, 2015, 08:11:11 PM »
J Thanks for the quick reply. I don't know any details to add I got my first look at the case just a few minutes ago and I'm very new at this, from the pictures I looked at today It is a NP 203 without a conversion kit an d yes it still has the auto locking hubs. I just read the tutorial on the NP203 part time kit and it was excellent, things are much clearer now. I think I can do this conversion after I read thru it a few more times. I like the 205 kit, that sounds like what I'm after. heck I didn't even know this truck was full time 4wd I don't want that. thanks again for this valuable info. Willie more question to come...

Offline Irish_Alley

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Re: NP203 conversion
« Reply #3 on: January 02, 2015, 12:22:17 AM »
the conversion kit gets rid of the full time 4x4. it will be cheaper to get the conversion kit than swapping with a 205 because then you have to find the right 205 and get driveshafts for it.
If you can’t tell yourself the truth, who can you tell it to?~Irish_Alley

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Offline Jason S

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Re: NP203 conversion
« Reply #4 on: January 02, 2015, 10:15:28 AM »
My $0.02,
The NP203 in full time form or part time converted is a very stout transfer case.  There maybe some strength gain with the NP205, but the NP203 is plenty strong and when converted to part time gives an additional gear range as well as 2wd option.
1973 GMC K2500, Super Custom, Camper Special, 350, TH350, NP203, 4.10's
1974 Chevrolet K10, Custom Deluxe, 350, SM465, NP203, 3.73's

"1) Peace through strength; 2) Trust but verify; 3) Beware of evil in the modern world"

Offline Willieb

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Re: NP203 conversion
« Reply #5 on: January 04, 2015, 08:33:49 PM »
I'm looking into a conversion kit for my 203 but have to finish up a VW Bus project. I need to keep this as  simple as possible for now. First I have to level the truck out because the p.o. put mismatched leaf springs on there. I bought a set off 73'  K5 Blazer when I bought the truck hopefully that will level it out.
What is involved in changing the hubs out? I got a set of manual ones off the Blazer when I got the springs. Thanx Willie

Offline FlatBlack77

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Re: NP203 conversion
« Reply #6 on: January 04, 2015, 09:17:50 PM »
the hubs are a pretty straight forward swap. as long as you take everything out, keep it in order, and reinstall in the correct order(along with manual parts) youll be good to go.
"When you are a hammer, everything looks like a nail"
'77 C/10 - 350/350 mild street motor