4x4 operations

webb06 · Dec 9, 2013

It's snowing here so I've been using 4x4 a little. When it's locked in for some reason all 4 wheels don't spin....it's like the truck picks which wheels are spinning which is quite inconvenient. Sometimes the passenger side spins sometimes opposite. Is that crap normal? I've got a factory limited slip rearend.

Dzchey21 · Dec 9, 2013

when you say the passenger or drivers side is spining are you talking about both the front and rear tires?

Generally with limited slip you should have both rears spinning and at least one front if not both spinning. It all depends tho if you have more traction on one side then the other both diffs can unload to one side like that. I would guess that if thats the case the limited slip has seen better days

webb06 · Dec 9, 2013

Dzchey21 said:
when you say the passenger or drivers side is spining are you talking about both the front and rear tires?

Generally with limited slip you should have both rears spinning and at least one front if not both spinning. It all depends tho if you have more traction on one side then the other both diffs can unload to one side like that. I would guess that if thats the case the limited slip has seen better days

Both front and rear on one side. Like I was coming up our driveway (uphill) and came to a stop just to screw around. When I stopped I slid down and off to the left so the trucks weight was mostly on the drivers side. When that happened only the passenger side was spinning...which is the wrong side that I needed to spin! Haha

Dzchey21 · Dec 9, 2013

is there equal amount of snow or ice on both sides or is one side dry and the other slick?

If both sides are pretty equally slick then you might have a limited slip issue. You might try and fluid change and new additive for it but most likely its toast already.

WoodBoy · Dec 9, 2013

I have problems with my rear sometimes only one tire pulling if off camber or something like Dustin said, but most of the time when I lock it in 4x4 both of my fronts will pull.

webb06 · Dec 9, 2013

Dzchey21 said:
is there equal amount of snow or ice on both sides or is one side dry and the other slick?

If both sides are pretty equally slick then you might have a limited slip issue. You might try and fluid change and new additive for it but most likely its toast already.

All snow/ice. But shouldn't both front turn? Or is it limited slip as well in the front?

backwoodsboy · Dec 9, 2013

Sounds like your L.S. clutches are cooked. Either that or too much friction modifier was added at the last fluid change. See this quite often when people use synthetic fluids that have a friction modifier built in, and then add the ford additive as well.

webb06 said:
All snow/ice. But shouldn't both front turn? Or is it limited slip as well in the front?

Factor front is a open differential.

Dzchey21 · Dec 9, 2013

webb06 said:
All snow/ice. But shouldn't both front turn? Or is it limited slip as well in the front?

front is open, so your at the mercy of an open diff, and essentially an open diff in the rear too from the sounds of it.

webb06 · Dec 9, 2013

backwoodsboy said:
Sounds like your L.S. clutches are cooked. Either that or too much friction modifier was added at the last fluid change. See this quite often when people use synthetic fluids that have a friction modifier built in, and then add the ford additive as well.

Factor front is a open differential.

I service the rearend roughly 15k miles ago. Used royal purple fluid.

Open diff means they both should spin?

Dzchey21 · Dec 9, 2013

no open means that there is nothing there to keep one tire from stopping, Front diffs on street truck pretty much have to be open, or selectable locker because they will want to push straight forward in the snow or ice when trying to corner. Not good LOL

webb06 · Dec 9, 2013

Dzchey21 said:
no open means that there is nothing there to keep one tire from stopping, Front diffs on street truck pretty much have to be open, or selectable locker because they will want to push straight forward in the snow or ice when trying to corner. Not good LOL

So they both should be spinning equally. Maybe I need to lube the hubs up. I'm thinking maybe the front left wasn't locked in and then after spinning it finally locked in.

Rear.....needs a true trac? Haha

Dzchey21 · Dec 9, 2013

no they dont, one tire might hold still on an open diff and the other will spin

Read this

http://www.ringpinion.com/Technical...ing_Differentials,_Spools_and_Mini-Spools.inc

backwoodsboy · Dec 9, 2013

webb06 said:
So they both should be spinning equally. Maybe I need to lube the hubs up. I'm thinking maybe the front left wasn't locked in and then after spinning it finally locked in.

Rear.....needs a true trac? Haha

Nope.
Open differential differentiates torque evenly between the two wheels, not motion. The tire with the least available resistive force (friction) will determine the torque applied to both wheels. Remember torque is a result of force. If you have one tire on a sheet of ice (no friction) and one tire on dry pavement (friction between tire and pavement) then the tire on ice will spin while the tire with traction will remain stationary. If there is no friction between the tire and surface it is on, then hypothetically no torque is required to rotate that tire. Essentially, both wheels are receiving zero torque as a result of the available resistance at the tire with the least traction.
Same thing will happen with an open differential during articulation if one tire comes out of contact with the ground. The tire in the air will spin, while the tire on the ground will remain stationary.

webb06 · Dec 9, 2013

backwoodsboy said:
Nope.
Open differential differentiates torque evenly between the two wheels, not motion. The tire with the least available resistive force (friction) will determine the torque applied to both wheels. Remember torque is a result of force. If you have one tire on a sheet of ice (no friction) and one tire on dry pavement (friction between tire and pavement) then the tire on ice will spin while the tire with traction will remain stationary. If there is no friction between the tire and surface it is on, then hypothetically no torque is required to rotate that tire. Essentially, both wheels are receiving zero torque as a result of the available resistance at the tire with the least traction.
Same thing will happen with an open differential during articulation if one tire comes out of contact with the ground. The tire in the air will spin, while the tire on the ground will remain stationary.

Hmmm that sucks