NP 205 vs NP 203 questions?

[wazzabie]

What is open differential and limited slip? The NP203 has a diferential where in 4Hi or 4low it can split the power 50/50 0/100 or 100/0. But put it in lock and it is 50/50.

Is there a differance between internal differential and open differential?

What is the differance in a NP205 between 4Hi and 4Low. Does 4Low act like the lock in the 203?

Is it good to run a NP 205 in 4Hi with gov-lock in the rear pumpkin?

Does the stock NP 205 have an open differential?

The stock NP 203 is it a limited slip? What is the converted NP 203 with part time kit? Does it lose the limited slip?

On NP 205 when does the indicator 4x4 light turn on? I know for the NP 203 it turns on only for Hi-lock or Low-lock.

With the NP 205 are there any advatages to having the syncronized case vs the non-syncronized? What does this allow for? What year was the transition?

 

[6872xtc]

That's a lot of questions at once!!! I think you understand how a 203 works from your first line. It has an open diff in it that gets locked in high and low ranges (1:1 high, 2:1 low) but it is not limited slip. The 205 does not have an internal diff because it was not designed as a full-time case. When a 203 gets a part-time kit, it will not put power to the front unless in lock. The 205 has 1:1 high range and 1.96:1 low, and locks the front to the rear in 4wd. It doesn't have a differential in it. Sorry, I can't tell you how sycronizing changed the behavior of the case because I always just lock the hubs and slide it in and out of 4wd as needed. I don't know when it changed either.

 

[76zimmer]

The 203 has a diff in it to help with full time hubs up front. That allows some slippage to take place, so the front wheels aren't fully locked in. The lock positions mechanically lock the diff in the rear of the case to allow no slippage between them.

Open diff means there is no mechanical means to make both tires turn the same speed under differing traction conditions.

A limited slip means the traction device provides sufficient pressure to the clutch plates in the diff to provide equal traction to both tires under differing traction conditions. Under extreme conditions (as in one tire in the air) there is still a difference in tire speed.

An internal differential is like the one in the 203 case, a open diff generally means no traction device in the diff of an axle.

4hi and 4lo in a 205 means gear reduction in the case. A 205 is 1:1 output in HI, and 1.96:1 output in LO range.

A 205 doesn't have a diff in it, but it will allow for 2 wheel drive operation, and 4 wheel drive operation. In 4HI or 4LO it will provide the same driveshaft speed to both axles.

A stock 203 could be considered a limited slip. With a part time kit added, it allows the front axle drive to be dis'engaged from the transfer case.

The 205 4x4 light should come on when either 4HI or 4LO is selected.

The syncro case allows for somewhat easier operation of the Lo range selection.
I believe the transition was around 85.

 

[thatK30guy]

The syncro case allows for somewhat easier operation of the Lo range selection.
I believe the transition was around 85.

I believe it to be around '83 or '84 as I have a 205 pulled from a K30 in the shop and it was one of those years. Just can't remember.

 

[imiceman44]

The 203 has a diff in it to help with full time hubs up front. That allows some slippage to take place, so the front wheels aren't fully locked in. The lock positions mechanically lock the diff in the rear of the case to allow no slippage between them.

Open diff means there is no mechanical means to make both tires turn the same speed under differing traction conditions.

A limited slip means the traction device provides sufficient pressure to the clutch plates in the diff to provide equal traction to both tires under differing traction conditions. Under extreme conditions (as in one tire in the air) there is still a difference in tire speed.
A stock 203 could be considered a limited slip. With a part time kit added, it allows the front axle drive to be dis'engaged from the transfer case.

.

The 203 is an open diff, and there is no slipage but compensation, as in the pinions trun from side to side keeping both tires rolling at their own speeds with constant power to both.
The 203 is not considered a limited slip, it's either locked or open.
The part time kit eliminates the diff and makes it a heavy 205.

To understand how an open diff works imagine having 2 vehicles you want to pull and you have one tractor, you attach both with a rope and put a pulley in the middle attached to the tractor, when you pull both can move at different speeds if they have different resistance and the pulley would move towards the faster vehicle.
Immagine that system in circle so that you never reach the other vehicle and stop the pulley, that is how a diff works.
The pinion gears are what make that happen.
I could do a search and find a video that explains it better but I think I answered you questions about the 203.
The 205 as mentionned does not have a diff it's pretty much 2wd or 4wd locked in both.

 

[wazzabie]

"The 203 is not considered a limited slip, it's either locked or open."

I have the gov-lock limited slip in the rear axel. Since I have this could I run the NP 205 in 4hi on dry pavement?

Also can a NP205 leak into the TH350 tranny?

 

[MTBLAZER89]

No its not good to run in 4wd on dry pavement at all. Straight line you would probably be fine, but as soon as you make a turn you'll know.

 

[wazzabie]

Can non synco NP 205s be shifted on the fly?

 

[onetonbb74]

if the front hubs are engaged, you can shift on the fly.

 

[blazinzuk]

But you can only shift from 2 to 4 not hi to low range.