hey,every truck i've ever had,when i would raise the rear end and spin the tires,one would go each way.the truck i now have,they booth spin together,does this mean there's a locker in it?i've had trucks with factory limited slip that spun opposite,so i'm thinking aftermarket locker?if so how can i tell?i've never messed much with rear ends?that didn't sound right,did it?

 

That means the carrier is broken inside.

 

broken?as in i should'nt be driving it till its fixed?not what i was hoping for,please help me understand better!

 

I'm not certain on how long it will last like this, but I would plan on fixing it very soon.

There is a potential that somebody welded the spider gears together, or that a spool has been installed, neither of which are to be used on hard pavement. A locker will still make the wheels spin in opposite directions.

 

A limited slip unit will rotate the tires the same direction when the tires are lifted off of the ground. That is normal.
The LS units that you claim turned the oposite direction is difficult to believe, but could happen if the clutches are totally wiped out. Even a little bit of tension will allow the tires to turn the same direction. If it had a true locker, chances are you will not be able to engage it by just turning one tire by hand. If ample torque is not applied to the diff, it will not engage.
You will know if you have a broken differential. Many noises, and the truck will stop making foward progress in a hurry. Does not take long to turn a diff into scrap metal after it breaks.

 

It'll groan a bit, but it will still work for quite a while, especially a 9".

A LS unit will spin opposite directions, as the clutches are forced together by load.

 

A locker will rotate the tires in opposite directions, but when you turn the driveshaft, and stop one wheel from turning, the locker will engage. A Gov bomb (GM)is an open diff until there is a difference of wheel speed, then engages(violently, then they explode). The Ford had either a Powerlock, or a Trac-loc. Both wheels will turn in the same direction when off of the ground. My guess is that you have a trac-loc, which is a limited slip that is barely good enough for pavement. Be carefull when driving on wet roads, snow or ice, it will take some getting used to.

Look on the tag on the Diff. IF its still there, you will know for sure its a limited slip, the gear ratio will read 3 L 55 or 4 L 10, and possibly will have an additional tag stating to use limited slip additive.

 

Tony is right, check the tag if it is still there, that will narrow down the troubleshooting.

I run Detroit True-Tracs in all of my trucks and race cars.

 

Of course, by now you should have popped off the diff cover and changed your fluid. Take a pic once you do, and post it. We will tell you what you have.

 

Clutch type units are pre-loaded with resatstance (springs, coil or "S" type), they always have this load pressing against the side gears. They can't spin opposite directions if both tires are off of the ground, unless the clutches are physically not there, or the springs are missing, and the unit acts like an open diff, allowing the side gears to rotate the spider gears.
I think you are confusing a helical LS unit such as the true trac. This works on a completely different principle. actually works the opposite of a clutch type LS unit, and does use a low traction condition to force the helical worm gears to spread apart applying more bias to the other axle. This is opposite of a clutch type system, that always has tension on the side gears, and relies on the spring to determine the point at which it slips. Hence the terms, "tight" LS, and "loose" LS units. Many manufacturers offer different springs to create a tighter unit.

 

allright,i got some pics but i can't figure how to get them on here?

 

Very top of page where it says "galleries" click on manage/create to start your gallery. It takes you through the steps. I haven"t figured out how to get pics in a post yet.

 

Ok, I think I have this now. Here are the pics
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also here are some numbers that i got off the big gear, 2 7 75 dana 30360 b3c10x 41-10 , thanks for any and all help!

 

i had a buddy of mines 79 f150 4wd jacked other day , and i spun his wheels , and they went the opposite , just like you say yours do ..... but he has a locker ....