My truck gets terrible traction on wet pavement. It helps to take off in 4WD. I can shift the transfer case in and out of 4WD while rolling which helps to make turns, but the hubs are manually locking so the front differential is always spinning. Basically, I’m wondering if it causes excessive wear on the drivetrain to drive around on wet pavement with the front hubs locked, both on the highway and low-speed urban roads. It would only be when it’s raining, and for fairly short distances.
When I ordered my Cherokee I had a choice between 4WD that could be used full time, or another one that could only be used on slippery surfaces. I opted for the part time 4WD option, which was cheaper and was all I needed. As with my old CJ2As, it was warned not to use 4WD on dry hard surfaces.
I just got out of bed, and the coffee’s not done yet; so I’m not sure of the details. But IIRC there was some slight difference in [something] that would cause the drivetrain to bind in those conditions – especially in turns. So 4WD could not be used on the street. There are times when the the roads were a little slippery (e.g., making a turn from stopped at a wet or snowy intersection), but not enough to leave 4WD on. I’d pull the lever for the turn and then go to 2WD once it was completed. This sort of thing happens when my tires are becoming a bit worn.
I think that rather than figuring out whether and when you can use 4WD as you desccribed, you might want to find the source of your loss of traction. A vehicle should not need 4WD in the conditions you describe. Just get new tires and only use 4WD in the conditions for which it was designed.
4WD locks the differentials, which mean all your tires MUST spin at the sames speed. The result is that going around turns (where the outside wheels need to spin faster) causes the rear end of the vehicle to kind of skate around the bend.
When you test out your 4WD you should always do it in snow or at least wet pavement, or even a gravel driveway.
I’m guessing the part-time 4WD had a locked front differential so that the front tires spun at the same rate when engaged. That’s how mine is. When turning, one of the tires has to skid a little bit. I’m not particularly worried about excessive wear to the tires. I’d only do it when the roads are wet anyway, so it wouldn’t be that bad. I’m just worried that since it’s only part-time 4WD, maybe the front differential isn’t designed to be used very often or something to that effect. It could be hard on the cv-axles too. I don’t want to break something.
And yes, it probably could use some better tires too, but I’m only borrowing the truck until I get one of my cars running again so I don’t want to spring for new tires. Besides, I think it may just be that they’re offroad tires and not suited for wet pavement. Combine that with very short gearing and a diesel engine and maybe occasional spinning on wet pavement is expected. I can prevent it at most intersections but some are just really bad.
Years ago I had an old Toyota FJ Cruiser. They didn’t come with hubs that could be unlocked, that was an option that was dealer installed.
IIRC, it was not necessary to have the hubs unlocked when in 2WD because, of course, the vehicle didn’t leave the factory built that way. The purpose of the hubs was to allow the front wheels to rotate easier and more efficiently when in 2WD. The front tires could rotate without the load of the front wheel drive train.
Therefore, if your drive train is at all similar, there should be no problem driving in 2WD with the hubs locked. It’s just not as efficient. It should not cause any damage or excessive wear on the drive train or the tires.
Also, IIRC, it was recommended that the vehicle be driven at least 10 miles a month with the hubs locked in order to keep the front drive train properly lubricated.
It’s not suprising that you get poor traction with a pickup truck in wet weather. The truck is designed to carry a load so if it is unloaded it will be “light” over the drive wheels and prone to slippage.
No, it doesn’t. The axle differentials remain how they are (open, limited slip, locked by a locker, etc.) but the 4WD engages the transfer case. Part time transfer cases do not have the ability to act as a differential between the front and rear driveshafts, which is why they can’t be used on dry pavement. Full time transfer cases can act as a differential, and can be used all the time. Without knowing what type the OP has in his truck, an accurate answer is not possible.
Agreed. The fact that the truck has manual hubs leads me to believe it is an older vehicle. AFAIK, manual hubs have all but disappeared. If that is the case, he doesn’t need to worry about driving the vehicle with the hubs locked even if the transfer case is in 2WD.
I used to lock & un-lock my hubs all the time years ago. I payed for that practice when the truck aged. the slider on the front drive shaft wore out, I was told it was a direct result of not rotating and just adjusting length.
Moot point for those trading off their vehicles every few years, Something to check if purchasing an older unit.
My truck today has automatic front axle, and the mileage is 180,000 very minor problems, and i am striking the wood with knuckles.
To the OP: If road conditions are such that you spin your wheels in 2WD, you won’t hurt anything by using 4WD.
This is not true. In 4wd, the front and rear differential inputs ARE locked together, but the front and rear differentials are not locked, unless they are specifically locking differentials (which are pricey aftermarket bits). Right and left wheels on each end can turn different speeds, but the average of the front, and the average of the rear wheel rotation rates will be the same.
When moving in other than a straight line, the front end always travels farther. This will cause binding of the drive line unless at least 1 wheel is able to slip.
Binding will also happen if the front and rear tires are not the same effective size, which can happen due to wear, inflation, or loading, even if they are otherwise identical.
If you are on a high traction surface, it is possible for this binding to get bad enough to break something. Something can include U-joints, Locking hubs, and in one case I witnessed, the output bearing housing of the transfer case.
Even if nothing breaks, binding puts heavy loads, and lots of extra wear on the various splines, U-joints, and gears in the drive line . It can load the dogs in the transfer case so much that it is difficult or impossible to shift out of 4WD. The solution is to stop, and try to shift out of 4wd while backing up and making slight S-turns.
Gbro, Driveline splines need to be cleaned and greased occasionally with a high molybdenum disulfide loaded grease . “Regular” grease (meaning every single product sold at an auto parts store) will only protect the splines for a few thousand miles before being scraped off. Hondalube-60 (60% moly) available at Honda motorcycle dealers is about the only suitable lubricant that is readily available. This is based on the exerience of folks who keep BMW motorcycles on the road for 500,000 miles. If these guys will stoop to using a Honda product, you can bet there is something to it. (BMW recommends an equivilent product made by Staiburings, (sp?) but it apparantly also contains lots of unobtainium in addition to the moly) Note that RWD vehicles with one piece driveshafts are designed so that the single spline in the driveline is constantly lubricated by the gearbox oil, (or ATF) so this is not an issue. Manual transmissin input splines (carryie the clutch disk) do tend to suffer from lack of proper lubrication though.