NP203 shift pattern

[78k10cd]

Hello everyone. I'm new to this board and 4x4s as well. I just picked up a 78 K10 short bed custom deluxe and was wondering about the transfercases. I'm pretty sure it's an NP203 since it has only a fill plug and no 3 bolt cover. I read somewhere that the speedo cable should be on the driverside, but mine is on the passenger side.

I also, wanted to know the shift pattern for it. I think it has the wrong shift knob. What should it look like, the one with 4 wheels or with the letters going up and down?

Lastly, what is this conversion kit that everyone is talking about for the NP203 and how do I know if I have it. I appreciate any help and sorry for all the questions. Thanks!

[77 Stepside Morph]

Here is a start on identifying your case....

darkwing.uoregon.edu/~jri...ubler.html

John

[78k10cd]

thanks for the link. I'm pretty sure it's a NP203 now.

Any help on the shift pattern/knob and the conversion kit? I'm really interested in converting to part time. thanks again!

[aprice]

Well to know if it already has the conversion kit you would have the lock outs in the front if not then its full time. i've never done it but also of you havent noticed everyone recomends to lock the the lock out once a week or so to lube the tail shaft of the t-case

the pattern should be

(front)
low loc
low
nutural
high
high loc
(seat)

[78k10cd]

thanks aprice! i went to a 4wheel shop and they told me it's a np203 and that if you have locking hubs, its already been converted, which they do. He also told me that I have the wrong shift knob of the np205, and that mine is:

(front)
4L
2L
N
2H
4H
(back)

He said I should be in 2H for regular driving, but it really matters only when you lock up the hubs. Can anyone explain to me what each position is for? Sorry for the newbie questions, again, it's my first 4x4. Thanks!

btw, anyone know a place where i can get a new shift knob for the np203?

[oscarone]

Let's start this with an np203 with no conversion.  It is a full time transfer case...that is, of course, all four wheels receive power at all times.  The shift pattern for this is:

(front)
Low Loc
Low
N
HI
Hi Loc

With this Hi is your normal driving position.  All four tires are driven, but, the front and rear axles are driven independent from each other.  They are free to turn at what ever speed.  This is done thru a differential in the transfer case like the one in your axle.  If you shift to Hi Loc you are still in Hi range, but, the front and back axles are now locked together and turn at the same speed.  Again, the same way a locker works on an axle.  The Lo and Lo Loc works the same way only using a lower range gear in the transfer case.

Now..part time conversion...There are a couple of conversion kits out there and I'm not sure which you have, so, I won't get into that.  The end result is the same with all of them.  The first thing is the locking hubs.  You are now able to disconnect your front axle from the wheel.  This prevents the wheel from "driving" the axle.  Now your shift pattern has changed...but, not much:

(front)
Lo Loc
Lo
N
2 HI
HI Loc

The only difference is the HI Loc has become 2 HI.  The differential in the transfer case has been"disconnected" so it will not drive the front axle.  And this is your normal driving position.

Make sense?
The Np203 shift knob dosn't have the shift pattern on it (at least mine doesn't).  The pattern was on a plate that mounted to the floorboard next to the shift lever.  You can try  competitor.com or classicindustries.com for both...

I'll keep my eyes open for them...I'll be looking at some stuff myself tonight.

[78k10cd]

thanks for all the info oscarone! i'm still a little confused. so, what he told me is incorrect. are the 4-and 2- designations even correct? are the topmost and bottommost positions when all 4 wheels are driven. sorry, i'm kind of slow on all of this. From your diagrams, the only thing that changed is the HI to 2HI, which i'm assuming is still for street driving.

i have no idea what kind of converstion i got, but I have B&M hubs. thanks for looking out for the shiftknob. just let me know. if you want to email me, you can @ wvicente@sbcglobal.net, so that we don't bore the rest on stuff they probably already know. thanks again!

[77 Stepside Morph]

Although it doesn't make any sense,  my truck has manual locking hubs on the front, NP203 Case,  but is still fulltime 4WD.  It does not have the conversion inside the case to make it part time.  I only bring this up so that you know that the presence of manual hubs does not necessarily mean that you have the conversion in the case....  Please don't ask me why the PO did this,  because he didn't have a good explanation for me.

Thank you for the lesson oscarone...  I learned a lot about my driveline from this thread....

John

[oscarone]

Hmmm...that's a good point.  I don't know why anyone would convert the hubs, but, not the t-case.  The t-case conversion is pretty cheap really, and, easy to install.  But, good thing you brought that up.  I guess the best way to tell would be to put the hubs in "free"...t-case in "hi" and try to spin the front drive shaft by hand.  It should spin.  What do you think?