99.9% of 4x4's have open front differentials. You have to look really hard to find a truck with a factory LS in front.

For tires, I really like Michelin LTX AT/2. I was very impressed with them in the snow.

 

Oh wow! How dumb is me?!! When I first discovered that my front end would chatter and bind up in a turn I wrote a post to the DieselStop forum and got an avalanche of replies that duhhhh, this is normal for a 4 WD and that there was nothing wrong with mine. Kind of figured they all did this.

About two years ago, I lived in a place where I had to haul my own water. My diesel wasn't doing too well, so I picked up a 1981 HD F250 4X4 for $700 to haul water. The TTB on that truck would chatter on pavement in a tight turn, but just a little and 90 degree turns were no problem unless the blacktop was totally dry. I just figured it was a less aggressive type, or it was worn out...

That truck had 4 brand new snow tires, and even with 2,300 pounds loaded on the back end I would get a spinning rear wheel in the snow. I know that good tires and weight help (always used to shovel the bed full of snow with my 1966 F250 2 WD), but I don't really think it really "fixes" the open carrier issue at all. The more weight you add is also the harder it is to stop the thing in the snow. I know from my nasty winter water hauling days that the empty leg of the trip was much less nerve-wracking than the loaded leg, even though I gained traction once the tank was full I'm glad I don't do that anymore, and I'm glad that I traded the 1981 F250 for a wastegated banks turbo for my diesel

 

The chattering you're talking about has nothing to do with whether the front end has limited slip. It's because you have the 4x4 engaged on a non-slippery surface. All part-time 4x4's, even ones with two open differentials, will chatter on dry pavement in 4wd when making a turn.

 

I'm not quite sure why it would bind and chatter if the differential was open, but OK. I'm still thinking that my D60 is LS because it really binds up and won't let you finish the turn... it will stall the engine. Do you check this the same way you check to see if a rear differential is LS (i.e. in neutral with both wheels off the ground turn and see if they both turn the same direction?) The D60/D70 manual says to check proper function of a LS you should raise one wheel and check the torque required to turn the wheel... it should be more than 40 ft lbs but less than 200 ft lbs. Not sure what an open differential would do, but seems like it should turn freely??

 

He's right, all 4x4's will bind on dry pavement. The front driveline is tied to the rear, and when you make a turn, the front is trying to do something different than the rear. You find slow parking lot type maneuvers cause the most trouble, when each front tire is trying to move in different directions as the steering wheel is turned, and the rear tires are pretty much not moving at all. In these situations, the factory limited slip mechanisms are not strong enough to cause problems, they just give way and slip.

And this is something that needs to be avoided if possible. If you are driving on patchy ice and snow covered roads, by all means leave the hubs locked in and leave it in 4x4. But if you are going to the store and are getting ready to park in a parking lot that has been scraped off and is dry pavement, just push the lever back up to 2wd before you make any turns, and it will keep you from breaking something. That is also proof that the limited slip is not causing the problem, since if you leave the hubs locked in, the problem is not there. It's only there when the transfer case ties the front and rear together.

 

Thanks Franklin, that was a very good explanation. If it's not LS causing the front to bind up, why do you suppose my D60 is so hard to corner compared to the TTB that I used to have? Do you think there is something wrong with it?

 

Maybe there was something wrong with your TTB. If you were running it on dry pavement and it wasn't chattering, then there was something wrong with it - probably a broken hub.

Or you might have a seized or stuck u-joint.

 

I want to raise the front end of my 1985 f 250 anyone used air bags in the coil springs?


Ron

 

Ron, welcome, I'm sure there are a few around that have done that but it's best to start a new thread then post in a different one. This way more people will see it. Also more information would be helpful, I'm assuming because you said F250 and coil springs you're talking about a 2wd.

Back to the issue at hand, I prefer a L/S in the rear, even in the snow. I've driven many 2wd vehicles in the snow (Pickups, and 2 different Mustangs) and most had L/S rears and while they have a tendency to weather vane down hill it's never been a serious enough issue to forgo the extra traction.

 

Thanks. With respect to a 4x4, is L/S more important in the back or front? Sounds like virtually all factory units are open in front. I guess what I'm getting at is if you were going to ADD an aftermarket L/S to one of your axles but not both, would you be better off putting it in the back or the front?