1978 K30

[necromonger]

this is my first 4wd I need a little help.It is full time 4wd what transfer case does it have? and how do i convert it to part time? It also has a sm 465 trans I got this truck cheap and i want to fix it up.




                                                                                                                                       Thanks
                                                                                                                                        Greg

[zieg85]

I am not a 4x4 person so I can't answer your question but I have converted a couple over the years.  It is a fairly easy conversion, at least the ones I have done.  My question is why?  You basically have all wheel drive now the best of all worlds IMO.  If you are looking for gas mileage I doubt you will see an improvement.  I would take an original full time set up over anything else mainly because everything stays moving.  My $.02

[Engineer]

Full time is a NP-203.

If converting to part time, and you already have a 4-speed, you should look for the gear drive NP-205 transfer case. They are plentiful, and cheap, and way stronger than a chain drive NP-203.

However, if it is a '78, and has a SM465, I don't understand how it would be full time 4x4. The SM465/NP203 combo is very rare, I have only actually seen one myself. They were only an option in 1973~74.

Can you snap a pic of your t-case? A pic would be very helpful.

But, one thing you can check yourself, the NP205 had a square ID tag. About 1.25"x3". This tag will be on the front of the case next to the front output shaft, and under the shift rails. The NP203 will have a round tag approx 2" in diameter. You will find this on the large chain (front output) housing.

[bake74]

   The sm465/np203 set up is actually pretty common in 73 -78/79 chevy's, my 74 and 77 both have them.  On the back side of your transfer case should be a tag, if not there snap a pic as engineer said and we can identify which you have, or go online and look up the difference yourself.

[necromonger]

It has a 205 in it.so this is better right?

[Engineer]

205 is the best OE transfer case hands down.

But the 205 is part time only. It was never built as a full time.

You thought your truck was full time, what indicated that it was?

[necromonger]

no lock in lock out hubs

[jdl71]

Something's probably been changed over the years. What is the shift pattern on your t-case knob? By no lock outs, do you mean they look like the newer auto hubs, or do they just have a plain steel cap over them?

[necromonger]

shift pattern is 4 low neutral 2 high 4 high.front hubs have a steel cap on them.

[jdl71]

Sounds like someone's swapped the front axle for a full time unit.

[thirsty]

Or it just doesn't have locking hubs on it. If this is the case just you can just put some locking hubs on it. I had a broken hub once and put the old solid hub gear on until I got a new set of hubs.

[necromonger]

So where can I get a set of locking hubs?

[rustymitchell]

Summitracing.com by mail order or your local auto parts store will be able to order them.  I believe you will also need the spindle nut kit as well.  Here is a link to the Summit page showing WARN hubs and spindle nuts:
http://www.summitracing.com/search/Year/1979/Make/CHEVROLET/Model/K30/Brand/Warn/?Ns=Rank%7cAsc

My search was for a 79 but your 78 will be the same.  There are other brands of hubs too (Mile Marker etc).  Also the spindle nut conversion kit picture is misleading.  It only includes the inner and outer nuts and locking ring and not all the other stuff in the picture.

[bake74]

So where can I get a set of locking hubs?

     Practically anywhere, shop around and find the brand/price you are happy with.  If you do not use it for serious off road, you don't need to spend the extra money for the high end hubs.

[necromonger]

Thank all or you for your help. replacing all the u joints now.




                                                                                                                                        Thanks
                                                                                                                                          Greg