Full/part time 4x4??

[chevy4x4]

When did chevy put part time 4x4 in blazers?
80?
I mnow if you have one with full time, you can convert it to part time with a simple kit.
How simple is this "simple kit"?
Is it true that on pavement you can get beter gas mileage with part time 4x4 then full time?
Thx
Chevy4x4

['73 K5]

I think it was 73-79. The conversion is pretty easy from what I hear and it will definitely help tire wear and gas mileage.

'73 K5
Chevy good...Ford bad

[Mudzer]

I believe most 70's models automatics had the NP203 up till about '79. If this is the 'case you are talking about, then I have one too. The Milemarker kit is just that - "simple". I would go the extra mile and purchase the rear output shaft kit to replace the complete shaft instead of just replacing the spider gears in the cheaper kit. I mean, you can do the cheaper kit, thats what I have but I would prolly go with the more expensive shaft replacement kit. One good thing about converting the NP203, correct me if im wrong, you can shift in and out of 4Lo to 2Lo and 4Hi and 2Hi on the fly. This means, with lockers you can shift into 2Lo on a tight section and make the corner. Most people with the NP205 buy the twin stick to do this, we dont have to when you convert to part time. Just reach down and shift. One problem, and it may just be my scenario, I have had the 'case pop out of 4Lo before when I really needed it. I broke the rear dif because of my lead foot and the 'case popping out of 4 wheel drive. I will always go a little easier when rock crawling and make sure it is in gear, plus I will check my linkage and mid mount. As long as the chain does not slip, you should get many miles out of either kit. But, expect some slack in your drive line after alot of miles with the cheaper kit, expecially if you have lockers that clunk and bang anyway. Good luck.

<font color=red>Mudzer</font color=red>
1978/91 K5 Blazer

[Waxer]

I HAD a neverending problem with my 203 popping out of 4low. I had it rebuilt with a new chain and it still did it. So I dumped the sucker and installed a fresh NP205.

I love it, no problems whatsoever.

[Goose]

I had a '77 4x4 shortbed that I converted the NP203 to part time. I didn't notice a change in gas mileage. It got horrendous mileage anyway, so I think I was out of luck either way. I did notice that I had to slow down a lot more when running curves on the sand roads. About lost it the first time I headed out to my favorite fishing hole.

Mud is just thick water, or is it that water is just thin mud?

[Blazer79]

I have a full-time NP203 in my Blazer. I'm really happy that way and I will keep it that way. I like the way it handles curves. I don't think that you will get an impressive mileage increase with the kit. Just think how much a kit and new locking hubs cost and how much gas that would be worth.

The best way to increase your mileage is to control your foot and not open the secondaries (if you have a Q-jet carb)I think you just have to get used to the fact that Blazers are hungry pigs.

<font color=black>//////
What the heck!...Drive it like gas is $0.50/gal!!!</font color=black>

[Grim-Reaper]

I have a 79 converted and a 75 unconverted. They both get the same millage. 79 on 31's and 75 on 32's. In fact the 75 gets better millage. the 79 speedo runs 3 mph slow and the 75 runs 8 slow. Without even correcting for that they both get 11 mpg. So the 75 is getting about 12-13. The 75 is brutal on the front tires in turns but it's like driving a monster truck. I can take turns much faster in the 75. Just put foot to floor and steer.

Diging it in the dirt with my K5's
Grim-Reaper