i have a 2004 f150 spercab lariat and when i put it in 4x4 hi and go around a corner the rear tire in the direction of the turn drags almost like the rearend is a detroit locker. i test drove another new one yesterday and it did the same thing. the owners manual doesn't mention this. anyone have any idea if this is normal? my other ford 4x4's didn't do this. thanks

 

First of all either it has limited slip or it doesn't, and based on what you said, I'd guess it doesn't.
The Ranger, and F150 4X4's have the same gear (LS or not) in the rear as the front, but the Superduty 4X4's will either have the LS or not in the rear with no LS in front.
Thus, when my buddy has his 4.10 LS 4X4 Ranger in 4WD, he can still turn fairly tight. When my 3.73 LS 4X4 Truck is in 4WD, my turning radious is greatly increased because the front doesn't have limited slip. I haven't checked the 04 F150's but maybe Ford did the same thing for this model year.

 

thanks for the info, rear diff is 3.73 limited slip, i have an appointment at garage in a.m. will post results

 

In the manual it specifically states to not use 4x4 on dry roads, I don't think driving like you are is good for your ride.

Brian

 

A guy like JMC can really explain it well, but 4x4 mode on dry roads is not good, especially in the turns in stuff, you can feel it starting to bind up.

If you're just putting it in 4x4 to keep it limber or whatever (during the summer) do it on the grass, or if you do it on dry pavement, make sure it's on a straightaway.

 

Yeah, I forgot to ask you the condidtions under which you were testing the 4WD. I "limber" mine up when the roads are wet, and only on the straighaways. Dry pavement is a BIG no no.

 

Yeah, if it binds up bad enough on dry pavement, you'll break something.

 

Its normal... especially on dry pavement...which is when you dont use 4X4. If you put it in Lo , and start twisting around and around on a dry road-- you have a very good chance of sending your drivetrain to an early grave.

Its kind of daunting if you've never heard/felt/seen it before, or never driven a 4X4. I remember the first time I drove a 4WD on a dry road in my other truck.... quite.. unnerving if you dont know what to expect.

 

It's jumping because you have at least two wheels spinning at the same speed, and usually on opposite corners (i.e. front right, rear left) These two wheels have different distances to tavel in the same time. Somewhere something has to give, and you have the "hopping".

Another way to look at it is: which is faster, the center of a spinning record or the outside? The answer is the outside because it has a greater distance to travel in the same amount of time as the center.

 

I know my mom's fairly new Dodge Dakota 4x4 really doesn't take it well on sharp turns. I don't even know why we have a 4x4, really, now that I think of it.

 

I've had a few 4X4's in my time starting with a '77 Ramcharger that had the NP203 full time four wheel drive transfer case (as opposed to all wheel drive) and most recently a '95 Dodge Ram 2500HD with part time four wheel drive. I now have an '02 F-150 2WD Lariat. Anyway, the best way to explain it is when you are tooling around town WITHOUT the transfer case engaged in four wheel drive, the vehicle performs just like any other 2wd vehicle. When you engage the transfer case into 4 wheel drive, the transfer case locks the front and rear axles together to demand they rotate at the same speed. If you are on dry pavement, there will not be any slip between the front and rear axles during a turn like there would be on dirt, grass, mud, sand, etc., and a bind would occur in the drivetrain leading to the vehicle coming to a complete stop, or worse, driveline breakage. If you do bind the driveline, the best way to UN-BIND it is to put it in reverse and back up going the same direction as when it bound up. The owner's manual will state not to run the vehicle with 4 wheel drive engaged on dry pavement. The bind up you experienced is normal for a 4X4. Even my '77 Ramcharger with open differentials front and rear would bind the driveline up on dry pavement when I locked the transfer case in 4hi. Do your truck a favor and never engage 4 wheel drive on dry pavement. Breakage will eventually happen.