First off, I searched :flipoff2: after 30 posts on NP203, I'm just gonna ask.

So I just bought this REAL PEACH of a truck:

http://i424.photobucket.com/albums/pp330/kingjason2006/79%201%20TOn/truck026.jpg

It's got a small block 400, TH400, and NP 203.

The front end has got manual hubs on it.

I don't want to put a bunch of work into it, I just want to use it on the farm, so I'm trying to get it driveable. Right now it's puking oil out the front output almost as fast as I can pour it in, and the 1 time I locked the hubs in and drove it it made a pretty severe pop from the t-case, I assume the chain slipping.

I'm wondering if since it's been converted to locking hubs if it's also got a part time kit in it. The shift knob does not have the usual Lock - High - Low - Lock marking, it has "2 wheel" and "4 wheel" written on it with arrows for 2 wheel pointing to the firewall and 4 wheel pointing to the seat.

Is there any way to tell without dropping it out of the truck if it's got a part time kit in it? If anyone recognizes this shift knob marking, can you tell me what the shift pattern is for it?

I'm trying to assess if I'm better off trying to replace the front output seal and drive it, or do some junkyard slugging and get another one that's in better shape.

Any useful input is greatly appreciated.

Foley

1 question....how sure are you that its a 203? I couldnt see them putting a 203 in a 1 ton.

Manual hubs and 2wd on the lever makes me think of a 400/205.

An easy way to id the case is by the lever. If its straight up its a 205, if its got a bend in it leaning it towards the front, its a 203.

Pics work to. Not trying to insult you if you are 100% its a 203, just doesnt seem likely is all.

Also a 205 is probably gonna do better for you then a 203 anyday. Especially since you are implying that it already has a Part time kit.

BTW thats still a nice truck, Dont hate it because its ugly.

I doubt that a 79 k30 has a 203 behind a th400, not saying that it isnt possible but I didnt think they put those in 1 tons.... Much like the above post make sure... get some shots of the Tcase up here.

1 question....how sure are you that its a 203? I couldnt see them putting a 203 in a 1 ton.

Manual hubs and 2wd on the lever makes me think of a 400/205.



I doubt that a 79 k30 has a 203 behind a th400, not saying that it isnt possible but I didnt think they put those in 1 tons.... Much like the above post make sure... get some shots of the Tcase up here.

They definitely used the TH400/NP203 in these trucks. Very common combo for K30s in the '77 - '79 year range.

I had a 79 reg cab dually with the same combo....check the t-case for sure what it is....

1 question....how sure are you that its a 203? I couldnt see them putting a 203 in a 1 ton.

Manual hubs and 2wd on the lever makes me think of a 400/205.

An easy way to id the case is by the lever. If its straight up its a 205, if its got a bend in it leaning it towards the front, its a 203.

Pics work to. Not trying to insult you if you are 100% its a 203, just doesnt seem likely is all.

Also a 205 is probably gonna do better for you then a 203 anyday. Especially since you are implying that it already has a Part time kit.

BTW thats still a nice truck, Dont hate it because its ugly.


I was stupified to find a 203 in there... I glanced under the truck when I bought it, saw the cast aluminum rear cover for the front output and ASSumed it was a 205. But unless there's another t-case you know of that has an iron housing, a range box on the front, and came behind a 400, it's a 203.

Incidentally it also has 1310 yokes on it. I'm guessing chevy half assed it cause it had a small block instead of a big block in it.

I'm also guessing since it drives with the hubs unlocked and the stick in one of the center positions (ie, not all the way forward or back) that it must have a part time kit in it, cause as I understand the workings of a 203, if it had manual hubs and was in one of the non Lock shift positions, it'd just spin the front driveshaft and go nowhere.

Well my 79 sub had the same combo as you, and it was a 3/4 ton. I guess they mainly used the 205 after 465's in the late 70's??

IMO if its leaking like a mofo, and making popping noise I would send it to the scrapyard. Swap in a 205 and get the driveshaft extended or better yet, take one out of a similar truck. With my trucks, I like to take the most reliable route. Murphys law is in full effect for me...:laughing:

If the truck was ever going to get more than 1/2 mile from the shop & barn I'd be right there with you.

Meanwhile, is my assessment right that it's got to have a part time kit in it to run like it does?

Anyone know for certain what the shift pattern is with that type shifter?

Anyone replaced a front output seal without dropping the case? If I drop that 300# bitch on the floor I'm going to end up either rebuilding it or swapping it out. I'd rather take the easy way since this is "just a farm truck" and resist my own temptation to over-build things.

if you can drive it without the front hubs locked you have a part-time kit. If not, you dont.

Not sure on the pattern.

I just pulled my 203 apart. In order to replace that seal you have to remove the yoke, and the aluminum cover and replace the gasket unerneath. Easy.

Starting at the front of the pattern (toward the firewall)

L lock
L
N
H
H lock

The lock positions locked up the t-case differential, so both axles were driven all the time. The part time kit eliminated the differential with either a solid shaft or some square cut gears. The solid shaft kit is the stronger of the two.

if you can drive it without the front hubs locked you have a part-time kit. If not, you dont.

Not sure on the pattern.

I just pulled my 203 apart. In order to replace that seal you have to remove the yoke, and the aluminum cover and replace the gasket unerneath. Easy.

Sweet, thanks.

Does napa know how to find the seal part number or is it a make your own out of cork kinda deal?

Starting at the front of the pattern (toward the firewall)

L lock
L
N
H
H lock

The lock positions locked up the t-case differential, so both axles were driven all the time. The part time kit eliminated the differential with either a solid shaft or some square cut gears. The solid shaft kit is the stronger of the two.

Yeah, got that for the stock shift pattern. No idea what the shift pattern is with the part time kit, most that I see are:

4low
2low
N
2hi
4hi.

I'm guessing that's what I've got. I guess I'll find out whenever it rains out here again and the pastures get muddy.

Right now everything's so hard and dry you can't tell what's grabbing and what's not.