I have a 2004 F-250 FX4 with the 6.0l and the 6 speed. I have the manual 4x4. Yesterday I put it in 4x4 HI. I put it in 1st gear and I as started out the truck bucked for about 15 feet. I was kindof turning. I put the transmission in nuetral, staightened the steering and started back in 1st and bucking went away. Today, I had the same scenario. In both cases I was not in a place I needed 4x4 (just a parking lot), I was engaging 4x4 in anticipation I would need it. Also in both cases the truck peformed fine after about 15-20 of the initial 4x4 engaging. I am just wondering if this is normal? Maybe it is because I have a 6sp?

 

You were binding up the drivetrain because you were turning on a grippy surface - highly NOT recommended, for the long term health of your transfer case, axles, etc. When turning, the front and rear axles (and therefore driveshafts back to the transfer case) turn at different speeds. Unlike an axle, there's no differential in a transfer case to deal with these mismatched speeds, so something else has to slip to equalize things. Offroad or in snow, it's your tires that slip. In a dry parking lot, it's more likely that metal parts will start shearing, but you got lucky and your wheels hopped up to let the tires slip.

If you just have the hubs locked in (but not in 4x4) in a turning situation, you will get some bucking of the truck, but this is just the unavoidable physics of highly angled u-joints in the halfshafts, and is more annoying than potentially harmful to the truck.

Duncan

 

Thanks Duncan, I definitely do not want to cause any undo harm on the truck. So should I avoid turning on grippy service is 4 wheel drive at all times, or is it okay after the 4 wheel drive is fully engaged? Deac

 

FroBozz are you saying its fine to leave the hubs locked all the time? and you will just have some bucking but wont hurt the truck?
ryan

 

never have yer hubs locked on dry hard surface (concrete, asphalt etc..)
then, you have nothing to worry about.

this is why i have ESOF, cuz i hate gettin out in the snow, mud etc...

 

Thanks Matt and Duncan, that is what I needed to know. I wanna take care of this baby so I get a couple hundred thousand miles out of her...Deac

 

Just how long a time, and how severe conditions does it take on dry pavement to actually do damage to the transfer case?

Mine has seen many a weekend day of mountain road racing, locked in 4x4 for hours on end...grinding and wheel hopping around turns at full throttle, pulling away from all but my friends AWD Subaru

I have done so on lots of occasions, and the truck has 11,600 miles on it now...never have I heard even a single cross noise or had a hard time engaging/disengaging the 4x4 system...

Has anyone actually done any damage to thier truck on dry pavement, or is this simply an outdated rumor reminiscent of much older days of trucks, like many things of the sort...?

 

I dont know i acutly drove around for a week with the hubs locked in but not engaged in 4wheel anything just locked hubs 80mph high way to and from work about 600 miles and as soon as i saw it is said oh you know what and un locked them but i dont think it did anything

i would love to leave them engaged all the time so i can shift without getting out but then again i shouldnt be that lazy........down here in Fort Lauderdale its not like gettting out in the cold to lock the hubs , and you just make sure you lock them in before hitting the mud and the tires are burried under haha.. that always stinks

 

That is funny, that is exactly what I thought I would be avoiding. I knew I was going to a mudhole 2 miles away, so I locked them on a dry parking lot thinking I was doing the smart thing, oops.

 

well, just driving with the hubs locked for a couple miles is not going to be a big deal, i just meant it would not be good to drive around with the hubs locked all the time so you only had to lock the transfer case.....i used to do that in my 78, and wondered why with an open front diff, and locked hubs in 2 hi it would still bind and make all kinds of noises..... if you do lock the hubs a few miles before a mudhole, leave it in 2wd, and do not turn real tight. doing this, i would be very suprised of any problem at all.
driving with hubs locked, and transfer case locked in on dry hard pavement, expect a broken u jount in the front axle, a broken hub, a broken case chain, or even front axle if you make it the norm, and certainly a reduced life of those items.

 

That's a pretty funny post about mountain racing on dry pavement and whether that will do any harm. Remind me never to let a 17 year old drive my truck.

I leave my hubs locked from time to time when pulling a boat. As I recall, the book said that was o.k., but mileage might suffer. I limit dry pavement 4x4 driving to launching the boat and parking the boat where I store it (have to back over a curb and can't get up it except in 4x4 lo). I launch the boat in 4x4 because I saw an unattended 4x2 with transmission in Park slide completely under the water at a boat launch in Galveston (Of course, it was a GMC, full sized though launching a jet ski on algea) In fact, that's the main reason I bought 4x4 in the first place, because I saw that 4x2 sink. Am I correct to assume that in 4x4 all four wheels are locked when in Park?

 

No need to get personal, it was only a question...

 

yes, but ONLY when the hubs are locked, and the transfer case is in 4wd...

 

Stock? You never have all four locked, even with Limited Slip rear, 3 at best. If you want all four get Detroit Lockers or equivalent upgrades. But, it certainly helps. Also, Park is not the best bet to hold a load on a grade, it can be broken.

 

Yep the bucking is normal on a dry, grippy surface. If you ever take a 4x4 wheel vehicle in to trade it in they will purposely do this to check the 4x4.

Now to deviate from the norm. First let me say I agree in not having your hubs in lock for everyday driving. But there are always exceptions to the rules. I, based upon were I live and the weather that I encounter leave my hub's in lock (with exceptions) for 7 months out of the year. I know and expect to have maintenance issues every 75,000 to 100,000 because of this.(This had been the average on the 6-4x4's that I have had in the past 15-years up North. Most of my front end problems due to having the hubs in lock seem to start at those millages given.) This is a fact that I except based upon the needed safety that is required. There are times were once section of road is perfectly clear and the next 100 miles is nothing but ice. The good thing is that most of those 7 months is spent driving to and from work on either ice, snow or slush. I will take them out of lock if the roads are in good condition and good weather is forcasted.That last sentence can be rare. I also try to take them out of lock if I am in town due to the constant turning but that also depends on current road conditons. Alot of people in Alaska keep them in lock during the winter. It's just one of those things. Come Oct until May we throw all of our ambulances and rescue vehicles in 4x4 and they stay that way.To add more injury to the front end I, like most other use studded tires. I prefer to have the added grip in the winter and will sacerfice the couple of thousand down the road. Seen and been to many accidents due to people slidding off the road in the winter. Its all in the priorities.

Minus the above and other specific situations I would not recommend keeping your hubs in lock.

PS. My last trip to Anchorage was 3 days ago. Had the hubs in lock both ways. I use Performance Service diesel additive and 22 mpg, hand calculated with the hubs in lock. I really havent seen any change in milage with the hubs in or out. Only when I use 4x4 do I see the drop. Always fun driving 15-mph in a blizzard for 300 miles. Alot of white-knuckle moments in those trips.