NP 203 questions
 

This last weekend, I bought an 83 that was originally a C20, but has been converted to 4wheel and has a 6in spring lift.

It currently has a 400 with th350 and np203. It also has manual lockers in the front.

When I have the shift selector for the transfer case all the way forward, the truck is in 2wheel, with the front drive shaft turning freely by hand. This is not at all like the shift pattern I am aware of for the 203.

What am I missing?

Thanks in advance for your help.

Re: NP 203 questions
 

Welcome!

Since your truck has manual lock-out hubs, the np203 has most likely been converted over to part-time operation. That basically eliminates the internal differential and turns the "Low" and "Hi" shifter positions into "2 Low" and "2 Hi".

The mechanism that was originally used to lock out the internal differential in the "Low Loc" and "Hi Loc" positions is still used to lock the front & rear driveshafts together. So those positions become "4 Low" and "4 Hi" on a part-time converted 203.

I'm thinking your shifter might not be moving far enough ahead to engage the internal diff lockout. In other words, it's only going into "Low" (2 low) but not all the way into "Low Loc" (4 low).

What happens when you pull the lever all the way back to the "Hi Loc" (4 high) position? If that engages the internal diff lockout (locks both driveshafts together) then I would think the t-case itself is okay and the problem is likely in the shifter.

It could be a linkage adjustment issue. But the 203 shifter mechanisms have an unusual gate mechanism that doesn't always work that great ... especially if there's old dried out and dirty grease inside. And the "Low Loc" position is usually the worst.

Sometimes you can get away with simply removing the shifter boot and spraying some penetrating oil down inside the shfiter mechanism and working it back and forth several times. If that doesn't do the trick, you'll have to take it apart for a more thorough cleaning and re-lubrication.

Re: NP 203 questions
 

Welcome
A 203 thats converted to run in 4X2, its recomended to be lubed
I start out in 4X4 ,shifter pulled back ,straight up
hubs unlocked,drive a few miles and shift forward into 4X2
should be good ,some people add a second fitting to the filler and add more oil
but this makes sure.
I sprayed lube underneath,shifter area,mine works much better

Re: NP 203 questions
 

Ray saved me a bunch of typing...
These shifters are shakey at best. A thorough cleaning and lubing will do wonders for it, but still not the greatest. If I had to run a 203, I would look into a twin-stick kit to eliminate the problem.

Re: NP 203 questions
 

Thanks a lot for the info, guys. I will do as advised and lube it well and see what it does. I will eventually be replacing the 203 with a 205, but it would be nice to know that the 203 is still working properly.

Re: NP 203 questions
 

I run nothing but 203's because I never want to be in 2wd. My old K20 shifted like butter for 20 years; couldn't ask for anything better. Then the chain went so i replaced it and used the shifter than came with it and it has been a bear to shift ever since. I bought my K10 a few years ago and that transfer shifts like a bear too. I see why they get the bad rap for shifting hard. I know they will shift like butter when everything is working right. With a 203 you rarely have to lock it in anyway so I see why the shifters freeze up and won't go all the way forward or back. They are both on my list for a complete lube job.