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[FMJ]

Question,

Is the generator in this truck run off the PTO on the transfercase?, does it also have the limited slip front axle?

Thanks!

 

[citizensoldier]

If its a true M1031 with the GM truck box not the M880 version the generator does run off of a T case PTO. They will have the NP205 case and a gov lock in the rear and a limited slip in the front.

 

[Recovry4x4]

gov lock in the rear

Actually it's a Detroit locker

 

[CCATLETT1984]

Kenny is correct, the gov-BOMB was only put into the m1009's

all of the truck variants got the detroit locker.

 

[citizensoldier]

Ok Ok you guys I knew you were going to hassle me after I posted that.. A locking mechanizm better than a posi was installed.. Was it just a limited slip in the front or a Posi ? Picky picky...

 

[CCATLETT1984]

front on all but the m1031/1028's is an open differential.

the 1031's and 1028's got the detroit truetrac posi unit.

 

[AJMBLAZER]

Nope, it's a Dana unit...I think the Tracsomething...forget which. The milder of the two Dana limited slips.
Don't think the TruTrac even existed back then.


For the record posi is just a former GM brand name for a limited slip. The use of the term posi to designate anything other than a limited slip is incorrect.

 

[Recovry4x4]

The front on the 1028 and 1031 is for sure a Dana unit. I forget if it's a traclock or a powerlock. Both operate the same but the Powerlock has 4 spiders vs 2 in the traclock.

 

[citizensoldier]

I have been told different?
Open = less traction always spins or power to least resistance
limited slip = most traction spins or most resistance spins
posi = both will spin when going straight regardless of traction
locker = both locked up going straight and just enough give for around corners? some ratchet some different type of mechanism example Brut locker, Detroit locker and so on..
When on a hoist turn one tire if the other does not move its open.. if the other moves the oposite direction its a limited slip if they both move the same direction its a posi.. This has been my exsperiance with GM products over the years.. K5 Blazers, Heavy half, 3/4 tons, and so on? 10,12,14 bolt GM corp rears.
Maybe one of the pro's here will chime in and fill us in on the facts.
When they were building the CUCV's in Flint we all tried like hell to get some of the units for our new civi trucks and couldnt do it.

 

[FMJ]

Tough Crowd.......lol

 

[AJMBLAZER]

Posi = limited slip. It's just a marketing term that's been taken into popular culture and bastardized a bit as to it's proper usage. There's a few different types of limited slips in how they work but basically they all will evenly split power when both wheels have traction but as soon as one looses traction the power will be diverted to it. Torque can also overwhelm the clutches/gears (hence the limited part) so they won't lock up completely like a locker.
The Grenade Lock is a pseudo locker that sort of locks up but not always. So it's somewhere between a limited slip and a locker. Some refer to it as a limited slip while others call it a locker and most know it as it really is...a POS. They wear out over time and are potential bombs in the half ton axles.




It's the TracLock then. I remember reading in 4-Wheel & Off-Road where they rebuilt the front of their project Army Truck and put a PowerLock in due to it being a bit tighter.

 

[ida34]

Posi = limited slip. It's just a marketing term that's been taken into popular culture and bastardized a bit as to it's proper usage. There's a few different types of limited slips in how they work but basically they all will evenly split power when both wheels have traction but as soon as one looses traction the power will be diverted to it. Torque can also overwhelm the clutches/gears (hence the limited part) so they won't lock up completely like a locker.
The Grenade Lock is a pseudo locker that sort of locks up but not always. So it's somewhere between a limited slip and a locker. Some refer to it as a limited slip while others call it a locker and most know it as it really is...a POS. They wear out over time and are potential bombs in the half ton axles.




It's the TracLock then. I remember reading in 4-Wheel & Off-Road where they rebuilt the front of their project Army Truck and put a PowerLock in due to it being a bit tighter.

I second. The positrac is a GM name for limited slip. The positrack and other limited slip use clutch plates and springs to control the spin. You check the clutch packs by seeing how much torque it takes to spin one side while the other is on the ground with the other jack up. Not an expert. I had a locker I put in a bronco but it was the one that replaced the spider gears. It did not have clutch plates and when it locked both wheels would turn no matter what. It did have springs that allowed it to disengage for turning but it still screeched around some corners. The point is no clutch plates in the locker.

 

[CUCVFAN]

I normally don't follow up to say "Yeah, what he said", but in this case, I'll make an exception, even if it has been corrected previously.

Front differential in M1028 and M1031 trucks is a Dana Trac-Lok.
Rear differential in everything EXCEPT the M1009 is a Detroit "No-Spin" AKA Detroit Locker.
Rear differential in M1009 is a GM Gov-Lock.

Positraction is a GM trademark, if I am not mistaken. Limited slip is just that. It allows a limited amount of slip within the differential. It's not "locked" (no slip), nor "open" (unlimited slip).

 

[doghead]

Not to confuse this topic but, what is the "name" of the optional rear "locking" differential in a current produced GM pickup truck? I seem to remember my local GM tech guy calling it a Gov lock(I think).

 

[mangus580]

Not to confuse this topic but, what is the "name" of the optional rear "locking" differential in a current produced GM pickup truck? I seem to remember my local GM tech guy calling it a Gov lock(I think).

GM's 'Limited Slip' that has been offered as a factory option for many years is indeed the

Gov-Lock
aka Governer Lock (works on a governer type setup)
aka G80 (RPO Code)

Its made by Eaton. They used to have a video of how it worked on their website, but its gone now.... good thing I had a copy... www.mangusnet.com/G80.mpeg

 

[AJMBLAZER]

AKA The Grenade Lock
AKA The Gov-Bomb
AKA That worthless POS...

 

[mangus580]

AKA The Grenade Lock
AKA The Gov-Bomb
AKA That worthless POS...

Honestly, I have had good luck with it. They work great for standard on road driving. Its when you like to do burnouts... or play offroad where they like to fail fast....

 

[AJMBLAZER]

...or they get old in half ton axles.

I had one in a '86 K5 with 1xx,xxx miles on it about ten years ago and in a 92 Blazer K1500 from 98-02 and I've now learned that neither worked. I always thought they were an ineffective limited slip. It wasn't until I was told how they operate that I realized how dead mine were. Normally they seem to blow up.
Personally know two people who had them blow up under DD half tons.

 

[citizensoldier]

How many times do you change the fluid and the additive in the pigs for the clutches? Without doing this on a regular basis the clutches tend to fail early. I have had good luck with them also even in half ton axles with a hopped up 350 and 3 speed with creeper.. I made sure to keep the drive line nice and tight with no slop and put in the additive..

 

[AJMBLAZER]

Every other year or so.

It's just a flawed design. For every story like yours there's a legion of folks who's Grenade Locks blew up, stopped working, or in some rare cases, locked up solid like a spool.