New old 79 K10 looking for info

[Kapdin]

Hello, So im not going to lie I come from toyota land but have never had anything against the chevy, actualy always wanted one to play with and now I got one. I got ahold of grandpa's 1979 chevy scottsdale k10 (has been sitting for ......5-6 years? prolli) and this is what i know of it so far (no build sheet in glove box). Its full time 4x4 with high/low and loc, its got the 350ci with the 4bb carb matched to a th350 tranny, and as we speek its running on propaine (do not care for).

So far I have changed engine oil and filter (super tech high milleage 10w30 with fram "tough guard"), pumped front and rear diffs (did not pull covers off)(super tech 74w90) drained transfer case (10w30), dropped tranny pan cleaned it and put new filter and gasket (super tech atf dextron III), new air cleaner, replaced rear leaf spring pack (2 broken leafs) with junk yard special.

First set of questions super tech a bad choice? lol, next by me pumping and not pulling covers also a bad choice? Third can i tell what transfer case it has from the out side? And also can i tell if it has lsd in the rear (when i pumped the front diff it was a caramel color and the rear was jet black) because i don't believe that super tech has the additive for it. I have many more questions but lets start with these.

Thanks.

 

[89Suburban]

Welcome aboard Lance. Got any pics?

Popping the diff covers off is best to get all the old crap out, and check for debris, clean off the magnet on the lid, and be able to inspect the rears.

We got some guys here very good at helping you identify that transfer case.

I run Super Tech oil in my boat's outboard engine.

 

[Stroked]

First off, welcome to GMSB

I don't think the supertech oil is too bad. But I've never heard anything good about a FRAM filter. Spend the extra $2 and get a good filter.

If it's full-time 4wd, then it has the np203 transfer case. And if I read you're post right, you put 10w-30 in it? I don't know of any t-case that takes motor oil, but I'll let one of the other guys chime in their 2 cents.

EDIT: Ahh, 89s beat me too it. Lol. Yea, pull the covers off those diffs and refill them with new fluid. With the cover off you will be able to tell if it has a limited slip in it or not.

 

[89Suburban]

If it's full-time 4wd, then it has the np203 transfer case. And if I read you're post right, you put 10w-30 in it? I don't know of any t-case that takes motor oil, but I'll let one of the other guys chime in their 2 cents.

That is the correct oil for the full time cases, or he can use 10W40, SE or SF grade.

The other ones take the Dextron II.

 

[89Suburban]

Welcome aboard Lance. Got any pics?

Popping the diff covers off is best to get all the old crap out, and check for debris, clean off the magnet on the lid, and be able to inspect the rears.

We got some guys here very good at helping you identify that transfer case.

I run Super Tech oil in my boat's outboard engine.

Ok, I just checked the manual and it says the oil for those rears should be 80W or 80W90 GL-5.

 

[HotRodPC]

Welcome Lance. The Tcase is a NP203 if it's Full Time, and has the Loc positions. I don't have a problem using the Super Tech brand fluids in these older squares. Having clean fluids is more important than what brand fluids you use anyway, and as much as I hate to say it, the Super Tech fluids are much more affordable so I use some of them too. ATF for sure. I buy it in the gallon jugs and it's over $1 cheaper per quart over the AZ, O'r and Advance that way.
Where's the pics???

 

[HotRodPC]

Ok, I just checked the manual and it says the oil for those rears should be 80W or 80W90 GL-5.

Really? For 10 bolts? GL5 is usally for Posi or LSD axles, but for standard open diffs, GL4 should be fine.

 

[Kapdin]

Holy crap you guys are quick on the replys I figured i was taking the short cut by not taking the covers off but they don't leak lol didn't want them to start but i will i hate short cuts. What kind of sealent to put them back on?

Yea I also don't like going cheap but you know i had no idea wat i was getting my self into here and low and behold a new batt. ad the thing fired right up no questions asked ( i forgot i also replaced plug wires and spark plugs) the old girl don't skip a beat. As far as grandpa's memorie goes nothing has ever been opened up on it and he says he has never had to "walk home", lol i take that as a good thing. I work in the power sports industrie and know all to well how bad gas is now adays and am scared what my fuel takes look like.... this lp gas kit lets you switch between the two but no one on the farm can tell me the last time it has been on gas..... the left take is missing a cap but the switch is on the right tank which does have a cap and says half full sooooooo maybe being half full better chanse of less rust???? or no? Also they seem to have put an in-line electric fuel pump under the hood... good bad or don't matter?

 

[89Suburban]

Really? For 10 bolts? GL5 is usally for Posi or LSD axles, but for standard open diffs, GL4 should be fine.

Maybe they are playing it safe, I dunno? I was actually pointing out that he used a lighter weight then recommended. But I am no scientist so I have no idea if it's fine to use or not.

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[Kapdin]

Also with that np203 and the loc is that a true locker? or like a 50/50?

 

[HotRodPC]

74-90W is the new 80-90W, so same same there. But yes, the GL4 or 5 can matter. I can't figure out why they'd call for GL5 though. No biggie, though, not a big difference in cost between GL4 or GL5. I'm rocking GL4 in mine and no problems. If I had LSD units or units with posi clutches I'd be more critical and use GL5 for sure or whatever the spec called for a minimum.

 

[DoubleDingo]

Welcome aboard. I would only worry about the gas being too old and gumming everything up. Definitely fill the tank with fresh fuel add some high quality carb-cleaner to it, put an in-line filter on it, and change the one at the carburetor. I just did that last night to mine. Now I can fill the right tank and not worry about crud going to the carb. And like the others have said, pull the covers off them diff's. Probably wouldn't hurt to service the front hubs. I found that out the hard when I got my dad's truck. I knew he serviced the hubs, didn't know he cheaped out and only did one side. Found out the hard way.

 

[Kapdin]

Yea i was going to short cut one more time and put a filter in befor the pump cus it looks like there is a small filter after the pump then i did read that there was a filter in the carb also huh? Next question....wat does a guy do with roughly 10+ wat evers in the other tank gallons of old ass gas? lol, big old bonfire.

This truck being full-time 4x4... (i guess i never did look) but thos hubs get serveced too? cus they are auto locking hubs.

 

[89Suburban]

74-90W is the new 80-90W, so same same there. But yes, the GL4 or 5 can matter. I can't figure out why they'd call for GL5 though. No biggie, though, not a big difference in cost between GL4 or GL5. I'm rocking GL4 in mine and no problems. If I had LSD units or units with posi clutches I'd be more critical and use GL5 for sure or whatever the spec called for a minimum.

Not sure. Now I'll have to go back and look at what I put in mine, lol. I still never put the LS additive in...

Also with that np203 and the loc is that a true locker? or like a 50/50?

True lock between front and rear, but not in the diffs.

 

[HotRodPC]

Also with that np203 and the loc is that a true locker? or like a 50/50?

Yes and NO, Sorta Maybe !!! All depends on your own definition.

Because the NP203 is Full Time, its' either in 4hi or 4Lo at all times. When it's in 4 hi or 4 Lo it works like your differential in the rear end with a peg legger. You only have one wheel with traction at a time, usually the one with the least traction. So your NP203 works the same way, except front axle to rear axle, so only 1 axle actually is getting power at a time, whichever one has the least traction. When you put it in 4Hi Loc, then the front and rear axles are getting equal power, and both axles are driven and the Tcase does not differenciate between axles, it drives both.

I personally don't think Full Time is as bad as people make it out to be. You're still only driving with one axle, just that is could be the front one, most likely the back one, and on Part Time, you know it's the rear axle only and NOT the front. Pro's and Cons to both systems, but NP203 is considered old school to most. Also on NP203, you have to keep your front hubs locked in. If not, you'd just spin and go nowhere, that's why most OEM NP203's you have fixed hubs, they are not unlockable either manually or automatically.