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NP203 headache need some help

johnatthebox

johnatthebox

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Vallejo, Ca.
I picked up a k5 project off of craigslist, and have some questions about the NP203 transfer case, and how it works. Since the NP203 is a full time 4wd, and I have a dana60 up front with manual hubs, does that mean I should keep the hubs locked all the time? I know a conversion kit is available, but its not in the budget at the moment. Any help would be really appreciated...
 
You should have 4h 4h lock 4l and 4l lock. Lock just locks the front and rear driveshafts together for true 4x4. I believe if you leave the hubs unlocked the vehicle may not move and the front driveshaft will spin. I haven't had access to one of those 77-79 models in many years. I just remember they were heavy compared to say a 208 unit.
 
The truck had no transfer case shifter in it so I just bolted a shift lever right on the shift mechanism on the box coming off the NP203. So, if i start with it pushed all the way forward, i want to be driving around with it in the second position back, and with the hubs locked?
 
Yes you need to lock your hubs in.

If not it will only move when the t case is in the lock position
 
You may want to check and see if it has a part time kit already, or confirm that it doesn't. Then you can figure out what will be necessary for the hubs.
Unless you have already done this....
 
I hope this isnt a stupid question(this is my first 4wd effort), but is that going to be ok for daily driving and going on the freeway with the hubs locked?
 
If it does not have a part time kit, then there is no problem running the freeway if all of the parts are up for it. Check the front driveshaft for loose U-joints.
To test it , you have to use your head and don't let the vehicle move unless you are in the seat so that you can use the brakes.
If you block the wheels, put the transmission in neutral, then unlock the hubs. Put the transfer case in high or low, but not in lock.
I would recommend having someone help by watching the front driveshaft. Then start it and see if it moves. If the front driveshaft spins and you don't move, then it is still full time.
 
If it has the kit installed inside the 203 with the front hubs unlocked you should be able to drive around in all lever positions except for neutral which is in the middle.

If it does not have the kit installed inside the 203 it will only drive around with 203 in high loc or low loc position with the front hubs unlocked.

Low loc is with the lever all way fwd and high loc is all the back.

That's with the correct shift lever installed.
 
Thank you all for taking the time to reply.
One more quick question_
Assuming I dont have the part time conversion kit, is it better to drive around in 4 hi with the hubs locked, or 4 hi loc with the hubs unlocked?
 
I would guess if it has a DANA 60 with hubs in it, it has a part time kit also.
 
You would assume someone who spent the money and time to swap a 60 over would have dumped the 203 as well. People are strange.
 
johnatthebox said:
Thank you all for taking the time to reply.
One more quick question_
Assuming I dont have the part time conversion kit, is it better to drive around in 4 hi with the hubs locked, or 4 hi loc with the hubs unlocked?
Click to expand...
You may have a better time driving with the hubs locked. The reason I say this is that I have seen some situations where the drivetrain was more calm with a little power to it.
See what you have and see what happens.
 
I picked up the truck as an unfinished project. It was all apart when I got it, and missing alot of stuff. It came with a 454, 14 bolt, dana 60, 8" lift, 35" tires, and no trans or tranfer case. I found a th350/np203 set up that was a fit for the driveshafts that I had, so thats what I used. I actually was told I had a np205 which caused alot of confusion when i tried driving it!
 
Are you sure it's a 203 and not a 205?

Otherwise the 203 was designed as full time with drive flanges not manual hubs so that should answer that question.

I personally have a 203 in my 74 K5 with manual hubs I installed in the front Dana44.

I drive in Hloc with the front hubs unlocked and have no issues.

I prefer to not have the bind, bounce when powering thru turns.

In the winter full time is nice.
 
blazer74 said:
Are you sure it's a 203 and not a 205?

Otherwise the 203 was designed as full time with drive flanges not manual hubs so that should answer that question.

I personally have a 203 in my 74 K5 with manual hubs I installed in the front Dana44.

I drive in Hloc with the front hubs unlocked and have no issues.

I prefer to not have the bind, bounce when powering thru turns.

In the winter full time is nice.
Click to expand...
As posted, if it is a 203, and not modified, then driving around with the front end locked is no big deal. But if it has been modified, driving on hard pavement with it locked up in turns can sometimes lock the front end up and as "Quoted" the "Bind" and the "Bounce" will change your mind "Quickly". Its no fun fighting a steering wheel that will not return, or having to get out and jack one wheel up so it can spin. On dirt or in wet weather the wheels can slip....on hard pavement......not so much.
 
I have determined that it is a 203 and it has been converted. Not sure if it was done the cheap way with wafers or the nash kit, but it definitly has been done. It was really getting confusing. Thank you to all who posted on this thread. Totally helped me out
 
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