Project Childhood.

[MunsterZ28]

I have a truetrac in the Camaro.

hows it do in the snow

[JoeliusZ28]

Because I don't plan on doing hardcore offroading.

The NP203 is a full time case with automatic front hubs.
There is a differential in the t case that when its in Hi or Lo acts just like a open diff, it sends power to front and back but if one starts to slip it automatically sends more power to it, as with the nature of open diffs.
When you put it in Hi Loc or Lo Loc it now locks the diff in the t case and sends 50/50 power.
So its always in 4wd all the time and has automatic hubs which are engaged all the time.
After 76 they switched to a NP205 which is a part time case.
You can convert the NP203 to part time.
A popular thing is to take the NP203 range selector and mate it to the NP205 and you can control the front and rear axles independently plus get 4:1 low ratio.

You could have
Hi, axles in lo/lo.
Hi, axles in lo/neutral
Hi, axles in neutral/low
Hi, axles in hi/hi
Hi axles in neutral/hi
Hi axles in hi/neutral
then repeat in low range.
So you could have 12 different settings to put your truck in.

You need a triple sticks for that.
Never put one axle in hi and the other in low.

From my understanding a locker is fine if you don't mash the throttle through a turn which why would you want to in a vehicle like this?

For my needs the Dana 44 and Corporate 12 should be just fine.
If anything I would upgrade the shafts to chromoly and in the front run Spicer 760 U joints.

I only plan on max 35"s but probably am going to go with 33"s because on 35"s and bigger you have to cut the fenders and I don't wanna do that.

Wow, thats a bizarre setup. Thanks for the education, i never knew such a thing existed. What about just swapping it straight up for a NP205, that is what the 3/4 and 1 tons used right?

Also how do automatic hubs work? I assume they are not electronic or vacuum driven so what is the mechanical way of doing it?

[Fox Slaughter]

Wow, thats a bizarre setup. Thanks for the education, i never knew such a thing existed. What about just swapping it straight up for a NP205, that is what the 3/4 and 1 tons used right?

Also how do automatic hubs work? I assume they are not electronic or vacuum driven so what is the mechanical way of doing it?

The hubs are mechanical.

The NP203 is a chain driven t case full time. They moved away from the full time cases and changed to the NP205 which is a part time gear driven t case.

http://offroaddesign.com/catalog/doubler.htm

This is the doubler, the plate you use to make one.

Far as what uses them I am not sure. The NP205 and NP208 replaced the NP203 in the Blazers.


As far as driving the Camaro in snow HAHAHAHAHAHA. No. =)

EDIT:

I am looking at the cut away on the automatic hubs and it appears to be a pressure spring that engages the drive gear to lock the hub in.

I need to take these ones apart and pack them with grease.
I haven't disassembled one, when I had the other Blazer my dad disassembled them.

Remember you're not suppose to run 4wd on dry surfaces because of the difference in the tire rotation.
Full time 4wd shoves that problem with the diff in the t case, unless you put it in loc.

[JoeliusZ28]

Right my cherokee had a "fulltime" 4wd mode that was similiar but i believe there was a "posi" type device in the tcase so it didnt just act as an open dif but it didnt hurt it to drive on pavement either.

When are the hubs supposed to engage and when are they supposed to disengage? What would be the reason for it to disengage if the front ds is always spinning but there is no bind? If the front hubs unlocked, wouldnt all the power go to the front and the truck would go nowhere if tcase is unlocked? My cherokee hubs didnt unlock at all.

[hoogiesngrinderz]

The front hubs on NP203 trucks do not unlock. I'm not sure why the word "automatic" got associated with those hubs.

My 86 was a 6.2 diesel but a PO put in a 305/TH350/NP203 so I had to keep the front hubs locked, truck would go nowhere with them unlocked.

The double kits are bad ass, and I thought about it. Then I realized that I would never need a 4:1 low ratio

[Fox Slaughter]

Yes the are just called automatic hubs. But they are engaged all the time. They never disengage.

What mike is saying with lock out hubs on the front if they are unlocked the diff will send power to the front only because there is less friction because it just spins the axle shafts. Now if he put it in hi loc or low loc you can drive with the front hubs unlocked.

If you want to run manual hubs on a np203 just convert it to part time.

[c0ncEpT]

Nothing wrong with a full case locker like a Detroit on the street. Do NOT put one in the front tho. One would think since you have lock outs you'd just be able to lock 1 hub if you wanted to drive it on the street in 4WD. We put a spool in the front of my buddys F250 and it was undriveable in the snow in 4WD on the street.

[hoogiesngrinderz]

If you want to run manual hubs on a np203 just convert it to part time.

I didn't want to go that route. NP203's use the chain to circulate the oil, part-time kits require you to put it into hi-loc every so often to fling oil around.

Driving with the front hubs disengaged and in hi-loc will quickly wear the internal coupler and eventually cause it to fail.

[JoeliusZ28]

Alright so seems like the ideal scenario to me would be swapping in an NP205 and manual locking hubs. All the functionality you need and would be less parasitic driving around since the front end wouldnt have to spin.

[Fox Slaughter]

There has been many studies on full time vs part time with hubs and it's not proven to reduce mpgs maybe 1 mpg. This is due to the np203 is running in 2wd until the say the rear starts to get more traction than the rear, then it sends the power to the front.

Its not running 50/50 until you put it in loc.

http://67-72chevytrucks.com/vboard/s...d.php?t=415273

The np203 to me is awesome because if you're driving you never lose traction and never have need to get out of the truck to lock the hubs.

[JoeliusZ28]

I'll beg to differ on that my cherokee drove easier with the front driveshaft out and GM/ford have invested quite a bit in front axles/hubs that disengage in 2wd.

With the 205 you could leave the hubs locked and never get out of the truck too. You would only unlock them if you want mileage or to do 2wheel low burnouts

[Fox Slaughter]

It depends on what transfer case you have. If you had it in Part Time as Jeep calls it of course it would run better without the front driveshaft as you aren't suppose to run Jeep Part Time on non slippery surfaces.

http://www.jeepkj.com/forum/f196/awd...ge-test-32988/

Here is an example of someone testing 2wd vs 4wd.

http://www.milespergallon.info/?make=Jeep&year=2000

If you compare the 2wd to 4wd models there is no difference if 1mpg.

[JoeliusZ28]

My jeep had 2hi, 4hi full time, 4hi part time, 4lo part time.

For the parasitic drag I was talking about running around in 2wd, since the hubs were locked full time the axles and DS always spun.

Edit: 1mpg is significant with an average in the 10-15 range.

[Fox Slaughter]

Joel you own the wrong cars if you are worried about getting mpg haha.

The one real life test someone did shows no difference in 2wd vs 4wd mode.

[JoeliusZ28]

Im just saying it would be nice to have on a 3 hour drive over to the sand dunes