A lesson in 4x4

[Magic1]

Ok. Guess I've been under a rock. I've always had a limited slip diff in any vehicle I've owned and guess I thought there were only limited slips and posi tracs. I've got an open diff in my 82 Sierra k10. Just recently found out what an open diff means. So here is some of my concerns and questions.
1. If my truck,  being that it has an np203 tcase, were to spin any wheel in 4x4, would I be stuck? Since an open diff let's the tire with the least amount of resistance spin would it matter whether or not it was in 4x4?
2. How would adding a locker to the rear diff affect drivability and would it hurt anything being that the truck has the full time tcase?
Sorry to seem like I'm rambling but until just recently I had no idea what an open diff was. I found out that's what I have in trying to troubleshoot my 12 bolt differential clunking noise and what I was gonna need to do to fix it. While I have it apart I figure I may as well do it right and put a locker or spool or whatever it needs to make it better. Would love to hear some responses from some of you more informed than I.

[zieg85]

A full time 4x4 in Hi, you are correct.  A posi in back still wouldn't help you much since it is usually the LF that would break loose 1st. (at least that was the case with mine).  Hi-Loc you would have the LF and RR doing the work together unless you have posi or LS in back.  I am sure the 4x4 experts out there will chime in...

[rich weyand]

Yup, without the NP203 in LOCK, full-time 4WD gives you four chances to lose.  You only need to slip one.

With the NP203 in LOCK, you have to slip one front and one back to get stuck.

With the NP203 in LOCK, and something like posi or the Eaton Gov-Lok, you have to spin both rears and either one in front before you're stuck.

[Magic1]

So what would be the most durable and economical choice for the rear end? Spool? Or locker?

[Captkaos]

You do not want a spool for a street driven vehicle.  A limited slip or EZ locker will work just fine.

[Magic1]

You do not want a spool for a street driven vehicle.  A limited slip or EZ locker will work just fine.

I sort of figured that but wasn't sure what the difference was between a spool and positive trac. As far as lockers go which would be a good inexpensive choice? I don't need anything as nice or pricey as an ARB.

[Captkaos]

A Posi-Trac is GM's name for a limited slip.  It has clutches to allow a certain amount of slipage for going around turns.
A spool is a mechanical lock between both axles.  Huge difference.
A locker is mechanical linkage that allows for releasing the inner axle for going around turns.

The most economical is a Lock Right as you just remove exising pieces in the open diff and replace them:
http://www.powertrax.com/index.php/products/lock-right

[Magic1]

A Posi-Trac is GM's name for a limited slip.  It has clutches to allow a certain amount of slipage for going around turns.
A spool is a mechanical lock between both axles.  Huge difference.
A locker is mechanical linkage that allows for releasing the inner axle for going around turns.

The most economical is a Lock Right as you just remove exising pieces in the open diff and replace them:
http://www.powertrax.com/index.php/products/lock-right

That shows ya how much I know about differentials. Lol. I knew what a locker was but wasn't sure about the rest. I've pretty much rebuilt this truck from the ground up but haven't had any experience with differentials. I appreciate the help. Figure if I gotta fix it I may as well take care of any weak spots.

[bd]

FYI -
The Powertrax Lock Right is a good streetable locker that is straightforward and easy to install.  The materials used in their construction are remarkably durable and should provide satisfying service life.  But, be prepared to hear a harsh BANG from the differential and feel a slight sideways lurch every time you corner as the locker releases.  The first time it releases in a turn, you'll be convinced the differential ate its lunch - LOL!  It will also have a greater tendency to squeal the inside tire as you accelerate out of corners.  Nonetheless, the harshness of locker disengagement will decrease over time as the locking pawls polish with use, though it may take a couple of years.

[Hollowman]

Spool is great, for dragracing! But since I don't even have one in my big block Corvette, I doubt it's a good idea for mudding. 

[Powerdriver1958]

I think you got the message on the spool but just for anyone that might think they can do it and get by ... I have effectively have spools in the back and front (Lincoln locked)but mine is a mud only toy . If the tries are aired 10 lbs different on any corner you cannot steer it on pavement .

When you hear spool please think of that as a full blown competition only part .

[Magic1]

I appreciate all the advice guys. Since originally posting this I did a lot of reading on the Internet about different rear end setups and think I'm gonna go with a locker like a Detroit or something simple. I'm not too concerned about the ratchet noise everyone mentions when coming out of a curve because I don't  drive it everyday and it's so loud in the cab I may not even hear it. 

[rich weyand]

I had a Detroit locker on the Safari AWD, and I have an Eaton Gov-Lock on the K-10.  I prefer the Eaton Gov-Lock.

The thing about the Detroit locker is that it will not unlock under power; you have to take your foot off the gas to unlock it.  Until you do, you are running straight axle, and bad things can happen, particularly on slick surfaces like packed snow.  The rear end will break loose and it's easy to end up in the ditch.  The Safari AWD came with a video and warning sheet on the Detroit locker.

The Eaton Gov-Lock will unlock at the correct speed even under power. 

[Magic1]

I had a Detroit locker on the Safari AWD, and I have an Eaton Gov-Lock on the K-10.  I prefer the Eaton Gov-Lock.

The thing about the Detroit locker is that it will not unlock under power; you have to take your foot off the gas to unlock it.  Until you do, you are running straight axle, and bad things can happen, particularly on slick surfaces like packed snow.  The rear end will break loose and it's easy to end up in the ditch.  The Safari AWD came with a video and warning sheet on the Detroit locker.

The Eaton Gov-Lock will unlock at the correct speed even under power.

Thanks bud. I'll look into them.

[rich weyand]

The Eaton Gov-Lock was the G80 option on the C/K trucks.  You can blow them up, but with normal use that seems unlikely.  The Detroit locker is indestructible without advanced weaponry.  ;-)

Eaton's newer stuff is considered superior:
http://www.ringpinion.com/technicalhelp/ContentFrame.aspx?FilePath=~%2FContent%2FParts%2FPositractions%2F%2FAn_Improved_Eaton_Positraction.inc

Here's an article comparing all the types.  Note the discussion of the Detroit locker with respect to ice and snow:
http://www.dragzine.com/tech-stories/drivetrain/geared-up-top-choices-for-eaton-performance-differentials/

And a forum discussion.
http://www.gm-trucks.com/forums/topic/100031-g80-rpo-code/