1975 k5 Blazer Newbie

[RaDSkater818]

hello i have a 1975 k5 blazer with 3/4 ton axles and i think it has a np203 transfer case front locking hubs.

and my problem is my transfer case feels like it has only 3 shift postions when i put the shifter in the up postion towards firewall with hubs free both drive shafts move while moving and the truck feels like it accelerates really slow and it makes a loud rattling noise once i pick up speed.

Then when i put shifter in the back postion towards rear with hubs free the trucks drives alot better and front shaft doesnt spin while driving.

My problem is i dont know what postion or setup
To drive truck in normal everday driving.

 

[nvrenuf]

You may have a 205, can you post a pick of the back of the tcase or the shifter?

 

[RaDSkater818]

You may have a 205, can you post a pick of the back of the tcase or the shifter?

Heres link to pics i snapped










post img

 

[Hogback Fabrication]

That's a 203 for sure. They're full time 4WD from the factory.

If your transfer case is stock, you'd need to keep the hubs locked in all the time.

 

[Desert_K5]

203

 

[RaDSkater818]

That's a 203 for sure. They're full time 4WD from the factory.

If your transfer case is stock, you'd need to keep the hubs locked in all the time.

Okay so i should have them locked postion and What postion do i put shifter in because with it in foward postion and hubs free it drive really slow and makes a rattleing noise once i reach like 20 mph

 

[grey88]

all the way forward is low lock, shift pattern starting from all the way back on forward is as follows, high lock, high, neutral, low, low lock. that's according to my shifter boot in my truck. I run mine in high and when I need 4wd I pull it back to lock the tcase into 4wd, but I think somebody has been into mine and put the part time conversion in it, cause I drove around for a summer without a front driveshaft. and as was previously stated with a stock 203 it wont do that. hope that helps if you were still trying to figure it out.

 

[blazer74]

Like grey 88 says.

All the way fwd or all the back is low loc or high loc, in stock form the truck will move in either of those positions with the hubs unlocked.
1 position from all the way fwd or 1 position from all the way back will be low or high and the truck should not move with the hubs unlocked.
If it a does someone has installed a part time kit in the 203 as well as adding locking hubs which are not the original hubs. Full time 203 trucks had solid drive flanges not locking hubs.
The 203 has an internal differential that sends power to the axle with the least amount of resistance (traction). Works just like an open differential axle.
When in either loc positions the internal diff is locked together and sends power to both from and rear axles equally.

If the tuck moves in high with the hubs unlocked that's where you want to be and your 203 has part time kit installed

If not yoour 203 is stock and you need to be in high lock

Also if you find you have the part time kit installed in your 203 you will need to engage high loc once a week and drive a few miles to lubricate the the rear output bearings due to design of the oiling system in the 203 which relies on oil splash.