1978 full-time 4x4. Is a 700r4 worth it?

[Redcap]

Originally Posted by Jankovic

I'm not bent on the 203. I just know that I have, on several occasions required 4WD due to snow and mud. It was very convenient to just throw it in 4wd. I wouldn't like getting out and locking the hubs when encountering icy/muddy terrain.

I want that convenience and just wanted to see if there was an economical option to save fuel as well.

haha I got the cake and want to eat it too!

You can always lock the hubs in and then drive it in 2WD when you get to that territory.

[nekkidhillbilly]

or use auto hubs. cake you can eat.

[Jankovic]

Originally Posted by nekkidhillbilly

or use auto hubs. cake you can eat.

I have read some awful, awful things about auto hubs... only work when you don't need them and fail when you do.

[Redcap]

Originally Posted by Jankovic

I have read some awful, awful things about auto hubs... only work when you don't need them and fail when you do.

That is about right.

[motornut]

Rocking back and forth "stuck" can make them autos engage /disengage
not a good idea with spinning wheels

[D13]

The key is, find your motors torque curve and gear for it. ALL my trucks run 1600-1650RPM at 55 - 5.3/4L60E/3.23 3/4 ton, 4.3/700R4/3.08 1/2 ton, and 6.2 diese/700R4/3.08 1/2 ton. Any less RPM, lugs excessively. Any more, wasting fuel.

One of th rare cases where math is your friend. But be honest - if you want MPG buy a Cruze and use your truck only when desperately needed.

[LONGHAIR]

You can't lug a carbureted engine down that low and expect anything out of it. The mileage will suffer as well as throttle response/driveability

You really shouldn't with injection either, unless you really never drive that slow....

[wilkin250r]

I've been thinking this same project. Of course, my TH350 and NP203 are in good running condition, so swapping them isn't as high a priority. But here are my thoughts and research:

First, I don't really care for all-wheel drive. It's an open differential between front and rear, so if any set of tires slip then all the power goes to them anyways. I don't believe it buys you anything substantial over 2wd.

I don't know about the NP203, but I know lots of people like the NP205, and they need to get creative to make it fit because of driveline clearance issues. The NP203 might be similar. Personally, I think you would be better off with a transfer case specifically designed to work with the 700R4 like the forementioned NP208 or NP241. If it's a money issue, I bet you could find a transfer case for possibly cheaper than an adapter for the NP203.

If the goal is milage, then I'd still advise you to dump the 203. Spinning all that front running gear is just eating gas. You want selectable hubs and the ability to just run 2wd.

If convience is your issue, I don't think there is anything devastating about running selectable hubs locked all the time. Sure, it will increase the wear and tear, but it can't be worse than an NP203 that is already running them locked all the time, right? I do this in the winter on my Ford pickup up and over mountain passes. Lock the front hubs, but keep the transfer case in 2wd. If I hit snow, put the transfer case in 4WD and I'm golden. I lock my hubs usually around early November, and unlock them around March.

Like I said, I'm in the same boat. I've got the same package, and I'm looking for the same change. I just don't see any major reason to keep that NP203. I researched it once, but I can't remember the reasons that led me to choose the 241 over the 208. But I DO remember they only had a speedometer cable for one year, and then they switched to electronic speedo. So I'm looking for a 700R4/NP241 combo from an 89 Blazer.

[nekkidhillbilly]

Originally Posted by Jankovic

I have read some awful, awful things about auto hubs... only work when you don't need them and fail when you do.

never had any problems on the 84 i had and it had a million miles on it. unless your doing some kind of severe offroading i dont see it being a problem. that said a new truck has no hub selector only thing goes out has nothing to do with the fact there locked. so i cant see it being a harm to leave em locked.

[Jankovic]

Originally Posted by wilkin250r

I've been thinking this same project. Of course, my TH350 and NP203 are in good running condition, so swapping them isn't as high a priority. But here are my thoughts and research:

First, I don't really care for all-wheel drive. It's an open differential between front and rear, so if any set of tires slip then all the power goes to them anyways. I don't believe it buys you anything substantial over 2wd.

I don't know about the NP203, but I know lots of people like the NP205, and they need to get creative to make it fit because of driveline clearance issues. The NP203 might be similar. Personally, I think you would be better off with a transfer case specifically designed to work with the 700R4 like the forementioned NP208 or NP241. If it's a money issue, I bet you could find a transfer case for possibly cheaper than an adapter for the NP203.

If the goal is milage, then I'd still advise you to dump the 203. Spinning all that front running gear is just eating gas. You want selectable hubs and the ability to just run 2wd.

If convience is your issue, I don't think there is anything devastating about running selectable hubs locked all the time. Sure, it will increase the wear and tear, but it can't be worse than an NP203 that is already running them locked all the time, right? I do this in the winter on my Ford pickup up and over mountain passes. Lock the front hubs, but keep the transfer case in 2wd. If I hit snow, put the transfer case in 4WD and I'm golden. I lock my hubs usually around early November, and unlock them around March.

Like I said, I'm in the same boat. I've got the same package, and I'm looking for the same change. I just don't see any major reason to keep that NP203. I researched it once, but I can't remember the reasons that led me to choose the 241 over the 208. But I DO remember they only had a speedometer cable for one year, and then they switched to electronic speedo. So I'm looking for a 700R4/NP241 combo from an 89 Blazer.

Thanks for the input. I am starting to come around to the NP208 haha.

[Jankovic]

Originally Posted by D13

The key is, find your motors torque curve and gear for it. ALL my trucks run 1600-1650RPM at 55 - 5.3/4L60E/3.23 3/4 ton, 4.3/700R4/3.08 1/2 ton, and 6.2 diese/700R4/3.08 1/2 ton. Any less RPM, lugs excessively. Any more, wasting fuel.

One of th rare cases where math is your friend. But be honest - if you want MPG buy a Cruze and use your truck only when desperately needed.

I'm not expecting superior fuel mileage with this truck. I just want to do whatever is cost/time-effective to try to get "good" mileage (10-14mpg). I will research the torque curve and try to optimize it that way. Like I said before, I heard that 2200rpm @ 65-70mph is ideal. By my calculations I would need 4.56 gears to do this.

[nekkidhillbilly]

my 01 ran 1800-1900 at 70 it was 4wd would never get under 17-18 mpg no matter how fast you drove it. most of the time was in the 20-21 mpg range. saw about 23-24 mpg once on the highway. i dont see that your lugging it like mentioned. most v8s dont lug until there under 1500 rpm. my dads 4.3 s10 was the same it was 67 at 1900.

[Flames97]

Jankovic,
I know what you mean about your 203/fulltime. I've thought about doing the same as your thinking and using a 700r4. But just in the thought process. May never do it. Anyways...along time ago I changed mine to part time and have regreted it ever since. I don't wheel or beat in my truck so I don't need a beefier transfer case. And I found that now when I am in 4wd it catches when I turn in a parking lot if there is an area that isn't slick. Also I find that I got even tire wear with the full time and terrible tire wear with part time. So some day I'll change it back.
Anyway just sharing thoughts and saying I understand where you are coming from.

[nekkidhillbilly]

Originally Posted by Flames97

Jankovic,
I know what you mean about your 203/fulltime. I've thought about doing the same as your thinking and using a 700r4. But just in the thought process. May never do it. Anyways...along time ago I changed mine to part time and have regreted it ever since. I don't wheel or beat in my truck so I don't need a beefier transfer case. And I found that now when I am in 4wd it catches when I turn in a parking lot if there is an area that isn't slick. Also I find that I got even tire wear with the full time and terrible tire wear with part time. So some day I'll change it back.
Anyway just sharing thoughts and saying I understand where you are coming from.

you wont have that with a 208/241 thats part of the quirks of the 203 kit.

[Flames97]

Originally Posted by nekkidhillbilly

you wont have that with a 208/241 thats part of the quirks of the 203 kit.

Ahhh...good to know!! Thanks

[Jankovic]

Originally Posted by Flames97

Jankovic,
I know what you mean about your 203/fulltime. I've thought about doing the same as your thinking and using a 700r4. But just in the thought process. May never do it. Anyways...along time ago I changed mine to part time and have regreted it ever since. I don't wheel or beat in my truck so I don't need a beefier transfer case. And I found that now when I am in 4wd it catches when I turn in a parking lot if there is an area that isn't slick. Also I find that I got even tire wear with the full time and terrible tire wear with part time. So some day I'll change it back.
Anyway just sharing thoughts and saying I understand where you are coming from.

Aaron, How did you part-time your truck? by converting the 203 over or by replacing it with a part-time transfer case (NP208, NP205, etc)?

[nekkidhillbilly]

he did the 203 conversion. i hear nothing but horror stories out of it from the jeep guys.

[Jankovic]

Originally Posted by nekkidhillbilly

he did the 203 conversion. i hear nothing but horror stories out of it from the jeep guys.

Yeah, I don't think I'll got that route.

So no wheel chirp wheel in 2wd with a 208 nekkidhillbilly?

I intend on putting a Detroit Truetrac in the rear end btw.

[nekkidhillbilly]

wasnt in the truck i had which was a k20 or the few k5s and k10s ive rode in. i dont see how it could really in the front the thing is completely free spinning in the shiftable 4wds when not engaged. its just like throwing a trans in neutral. the later trucks like my 04-01 your hubs stay engaged even and ive never had that issue. now ive had rear posi do that in curve on a hill some times but that has nothing to do with a 4wd system since its occured even in a 2wd truck ive driven.

[Flames97]

Originally Posted by Jankovic

Aaron, How did you part-time your truck? by converting the 203 over or by replacing it with a part-time transfer case (NP208, NP205, etc)?

I used the mile marker conversion.

[Jankovic]

Well from what I've been reading, the first step is definitely a vacuum gauge regardless of the gearing and transmission. I just might be steering to the 700r4 - np208 - locking hubs configuration.

I like the idea of just keeping the hubs locked in the winter months and unlocking them in the warmer months. Being honest with myself, I have got stuck in snow way more than in mud. Mainly because if it seems muddy, I stop and ask myself whether it is worth it. (stuck, get out walk, get a tractor, or go to the neighbors and ask for their tractor all the while in a soupy mess). Snow isn't as bad.

I'll chew on this for a bit. Whatever install I do, I will be back on this thread to update what configuration gave me the best fuel mileage. I plan on working on the truck once the weather warms up (currently -19C or -2.2F haha).

[nekkidhillbilly]

i odnt think you will complain with the set up at all. how healty is your engine btw you may look into a ls/60e swap with the 208 if your going to need a better engine soon anyhow.

[cadillac_al]

Running your front hubs locked while in 2wd on ice is going to make for some funky handling. Those front wheels aren't going to roll as easy as being unlocked and will be sliding instead of rolling. You don't want to learn that the hard way. If you don't need all wheel drive in your climate then a part time transfer is all you need.

[nekkidhillbilly]

you do realize that all trucks built in the past 20 years besides superduties have the front wheels locked all the time from the factory. i just drove my 04 in 2wd on ice you dont notice it really.