Newb 4x4 Questions

[Mil-Spec]

Hey guys.

I picked up my 1st 4x4 truck back in Nov. It's a '79 K20 Suburban. The recent snow we recieved here in Ohio (13 inches in some places) has been the 1st real time I got a chance to used the 4x4 function. It felt great and had a real good connection to the unplowed surfaces.

A couple of questions I had after driving around with the 4x4 engaged:

1. When I turn the wheels tight in either direction, while moving forward I feel the frontend jerking or what feels like binding. Is this normal for these straight axle trucks?

2. When not using the 4x4 function and with the hubs not locked. Is it hurting anything by leaving the transfer case in Hi-loc? I know the know the knob on the shifter handle says Lo-Loc, Lo, N, Hi, Hi-loc, but it doesn't feel like I have that many detents or selections. Should it definately be in "N" when not using 4x4?

Thanks

[Chevy1TonFun]

Yes, it is normal for a more aggressive grabbing when your steering clocked to the right or left.

Second, all drive power goes through the transfer case. In your case it is a NP203. So if you were to put your t case in N it would be the same as putting your transmission is N. As for Hi vs. Hi-loc, I am not familiar enough with the 203 to know what the recommended gear setting. My guess would be Hi.

[msgross]

Hubs locked? do they have locks on them? unless someone did a conversion then it should have smooth caps over the front hubs.

My 79 blazer had a 203 transfer case (sounds like yours does). Do some reading on the NP203, it's a full-time 4WD case that is always able to turn the front or rear wheels. When you put it in Hi-loc then it's a real 4 wheel drive truck.

The sharp turns in 4WD should be avoided on dry ground,

here is some info
http://www.4wheeloffroad.com/howto/47538/index.html

[Mil-Spec]

Thanks Rid'in High and msgross.

I'm just starting to become familiar with these trucks, so that's why I'm deferring your guy's knowledge.

It has WARN hubs on it now. I supposed it could have been converted. The Suburban was refurbished and used by a local Fire Dept in 1990 and then sold off in 2003. It even still has the Lights & Siren.



From the factory it would of had smooth caps on the front? The only 4x4 versions of these trucks that I've had exposure to have been the CUCVs which also had locking hubs.

Thanks for the link, I'm gonna start reading after I send this reply

[msgross]

my 79 Blazer had smooth covers on the hubs... it could have been converted then.

With the hubs unlocked and the TC in Hi will the truck move? If not then it only had a hub change and not a TC upgrade. If it has to be in Hi-loc to move then that would also support that idea.

[Benelli]

Theres the chance that the PO could have just put in the hubs and not converted the t-case. I've seen it a few times.

To find out, unlock your hubs, slap your t-case in Hi and see if it'll spin the rear tires when you floor it with the brakes on. I would do this on gravel so it's easier on your tires.

If it spins the rear tires then it has a part time kit and you NEED to drive it in four wheel drive once every fill up or you'll burn up your transfer case.

If it just makes noise and doesn't move then it should still be full time 4wd and you might as well leave the hubs locked because they're not doing anything.

[cowboymike51]

my brother has a 79 chevy pick up and it has a granny 4 speed in it, with a 205 trasnfer case and warn lock out hubs up front and it is all stock.

[Mil-Spec]

It has been converted.

I flipped down the sunvisor yesterday and found a 4 placards. Two appear to be factory applied, 1 about the emmisions with an image of a catalitic converter on it and the other stating that the truck is a full-time 4x4 and goes on to give instructions on how to use the T-case selections.

Next two appear to be applied later. The 1st one is about the WARN lock-outs and their usage. The 2nd is a placard stating that this vehicle has been converted to part-time 4 wheel drive by DOUG NASH EQUIPMENT of Franklin, TN.

Does anyone here know more about DOUG NASH EQUIPMENT and what all is involved in their conversion process?

I plan to call the F.D. that used the truck and ask them if they had the conversion done or if it was a PO or the dealer. I'll post pics of the placards after work.

[ghettoluxury]

Originally Posted by Benelli

If it has a part time kit and you NEED to drive it in four wheel drive once every fill up or you'll burn up your transfer case.

I have been running 203's with part time kits for years and have never heard such a thing.

Originally Posted by Mil-Spec

It has been converted.

Next two appear to be applied later. The 1st one is about the WARN lock-outs and their usage. The 2nd is a placard stating that this vehicle has been converted to part-time 4 wheel drive by DOUG NASH EQUIPMENT of Franklin, TN.

Does anyone here know more about DOUG NASH EQUIPMENT and what all is involved in their conversion process?

Doug Nash made the part time shaft as well as Mile Marker (who is the only one still producing this part). If you look at the back side of your transfer case ther is a round cover on the lower portion this is removed to access the shaft that is changed out.

[Mil-Spec]

Originally Posted by Benelli

If it has a part time kit and you NEED to drive it in four wheel drive once every fill up or you'll burn up your transfer case.

Originally Posted by ghettoluxury

I have been running 203's with part time kits for years and have never heard such a thing.

Actually interestingly enough the DOUG NASH placard does state that the 4WD should be used atleast once a week.

Wish i had realized this before, but it seems to work fine so far.

[msgross]

I also "heard" that Mile marker bought the Doug Nash design and is the only one selling the conversion.

[Mil-Spec]

Just getting around to uploading these pics for anyone who might be interested.

Placard for a long since gone catalic converter.


Full-Time 4x4


WARN Lock-outs


Doug Nash Equipment & Enineering (DNE2)

[70jimmy]

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[84 400]

Okay here you go. Mile marker bought the doug nash rights in the late 90's. Mile marker is currently one of if not the only company still making this kit. Being a doug nash you have the best kit available at the time... The full shaft replacement kit!!!

You should be in 4 hi while driving on the street.

here is your old shift pattern for the transfer case
lo loc
lo
n
hi
hi loc

and now
4 wheel low
2 wheel low
N
2 wheel high (street driving)
4 wheel high

here is the original install instructions provided by a fellow board member
http://67-72chevytrucks.com/vboard/s...ight=doug+nash

here is a vid i made about how to install and remove the kit. IT might help give you a better understanding

YouTube- How to convert an NP203 from fulltime...

[OrrieG]

I converted my 203 with a Doug Nash shaft in 1985. I had the rest of the transfercase freshened up at the same time (new chain and chain gears, every thing else was ok). I drove it as my daily driver until 1998 averaging about 6-8k miles per year. I did not do anything special between the regular snow we used to get, fall hunting and summer camping trips 4wd got used at least once a month. This build I pulled the chain cover and found everything looks ok, buttoned it back up an expect to use it the same way when I get back on the road. If yours does not get driven off road often then you probably should exercise the hubs and tranfercase once a month or so, but not on asphalt. I suspect the once a week or every fill up warnings are just ways for manufacturers to void warranties.

[winchster]

Originally Posted by OrrieG

I suspect the once a week or every fill up warnings are just ways for manufacturers to void warranties.

Actually, it is for the health of your transfercase. My research and in my travels to discover all I can about my new ride has led me to the following opinion, that seems to be widely held around the 4x4 community:
If you didn't have any problems then you were lucky. The oil pickup only functions as a result of shaft rotation. It is recommended on a daily driver to lock the hubs and drive to work once a week.

[84 400]

you do not need to lock the hubs to drive the front shaft. simply shifting into 4x4 with the hubs unlocked will turn the front output spinning the oil pump. Thus it can be done on dry pavement since power is not reaching the tires. So if you want to fallow the sticker to a "T", shift it into loc position after fill up. you will hear some noise since the front shaft is spinning but if your hubs are working right it will not hurt the axle joints, stretch your chain or other related parts.

Also for those who installed the hubs and not the part time kit this is not the way to go. It will cause premature wear on bearings. With out force back on the front output over a prolonged period of time slop will develop.