Front Diff rotates in 2wd?

So quick question. I have been getting mixed info on this so i wanted to see what was the case from TW. Does the front driveshaft rotate in 2wd when driving around. In this video it shows the front driveshaft does not rotate and also when i am rotating mine (unistalled from truck) by cv the flange doesnt roate either. So im thinking it is just the spider gears that rotate in 2wd?

https://www.youtube.com/watch?v=fHk8hVXzVeI&feature=emb_title

 

Yes, the CV’s always rotate.
No, the front driveshaft does not rotate in 2WD.
In 2WD, the front shaft is disconnected from the transfer case and the front diff.
Makes greasing the zerks much easier.

All is normal.

 

Thats what i was thinking. So when CV are rotation its rotating through the spider gears correct?

 

Yes, the spider gears are spinning like a ground bloom flower on the 4th of July. That’s the way it’s designed. Doesn’t hurt anything.

 

my thoughts exactly. so on a regear you would need to engage the front diff to get ring in pinon turning correct?

 

As muddin said, yes.
That’s why it is a good idea to change the front diff fluid regularly.


When you do, go ahead and pick up this drain plug.
That way you don’t have any issues later, when the allen rusts and starts to strip.
https://www.tacomaworld.com/threads/front-diff-drain-plug-alternate-oem-part.604989/

 

The front driveshaft LIKELY wont turn in 2wd, but there is nothing stopping it from turning. So at higher sustained speeds when everything is warmed up it does have the potential to spin somewhat due to the driver side CV turning while going through the main carrier.

 

The front DS won't turn due to the ADD disconnect now you put an FJ PS stub shaft in when you are going in a straight line it can turn. But it wouldn't do anything because the tcase is then disconnected. It's like keeping your hubs locked on an older solid axle vehicle, the ADD took the place of locking hubs.

 

Ahhh that makes so much sense! Thank you for the info!

@whitedlite

 

So if I regear the rear but gotta wait a couple days to do the front will that be okay?

 

If you were to do this, don’t go into 4WD.

 

Yeah it’s mainly just not having the time to do it all at once. Want to the rear one weekend, be able to go to work, then do the front the next weekend

 

I don’t see a reason you couldn’t do it.
Just make sure no one (kids?) can engage 4WD.

I’ll tell on myself here.
I once switch in to 4WD, while meaning to switch on the A/C.
Don’t know why I did it (it was early in the A.M.), and I was going about 50mph. (Which would be bad in your case with different gears)

 

Haha I’ll be sure to put some tape over it or something

 

Pull the front driveshaft and it won’t matter if you put it in 4WD.

 

Good idea

Remember to mark it, and put it back in the same way.
I honestly don’t know if the front is balanced?
But it can hurt to put it back in the same way?

Is the front balanced?

 

All driveshafts are balanced, and lots of people say to mark the flanges when you pull it. However, look at it this way. When the truck is built, it goes down the assembly line and someone bolts in the diffs. Then it goes farther and someone grabs a driveshaft out of a pile of driveshafts and slaps it in. There is no way that they balance the driveshafts with the yokes and then send the yokes to the axle assembly department for assembly and then keep track of which axle and transfer case goes with each driveshaft. I would venture a guess that the axles and transfer cases aren’t even assembled in the same building as the truck.

 

I always try to put them back in the same orientation that they were in when I removed them, but you are correct and it should not matter.

 

The driveshafts are balanced they are not matched or balanced to the rest of the driveline. Even if you have one made for you they aren't done that way there is no way to balance a driveshaft to the driveline. When people talk about a driveshaft being in phase they are talking about the u-joints and the slip yoke if it has it. The slip yoke is
in a certain position and if you 180 it even though your u-joints will still be aligned correctly it still can be out of balance.

it doesn't matter. This is one of those old wives tales from when vehicles were first created and they used a torque tube and correct orientation was more critical. Also think of a 2wd where the slip yoke is with the transmission and not the driveshaft how do you know you have the correct spline in the output shaft of the transmission when reinstalling.

 

My front tires are locking up in 2WD when I go over ice while turned sharply(like pulling in to a parking spot). No traction control light comes on the dash. Could this be my front diff binding?