4wd

[cnuttgirl]

I have a 99 4WD XLT Expy with 73600 miles. I dunno a lot about 4WD. I know when and how to use 4H and 4L, but i don't know as much about the sounds that you hear when you are in 4H. My husband was concerned about me driving in torrential rains this past weekend and asked me to use 4H. I noticed when turning, really weird sounds. The kind I heard last winter in the snow and assumed it was the snow moving under me. Kinda like a popping, and i notice that the truck kinda slips around...like the rubber can't quite grip the road, but it's trying really hard.

is this normal when on wet/rainy surface?? or should i have something looked at?

thanks in advance for any insight.

 

[rwinch]

This is a reponse I gave to a previous post to a similar question:

"As most 4x4 owners know, driving a 4x4 on dry pavement while turning causes issues (mostly bad) due to the fact that ALL wheels are now turning at different speeds due to the different turning radius they are experiencing. The rear wheels usually do not have that much of a turning difference since they are locked in a forward facing aspect, but the front wheels can't compensate enough through the front differential (which is an open type) when locked into the same speed input through the center diff as the rear diff. What happens is that EITHER 1) the inner tire is made to slip on the dry pavement (it wants to turns at roughly the same speed as the outer tire, which wants to turn faster because of the larger turning radius) or 2) hop & spin as the inner half shaft gets wound up, and then releases its energy (it acts like a torsion spring, which is also the cause for torque steering on front wheel drive cars). It all depends on how well the tires grip on the dry pavement. In any case, bad noises will be percieved from the front end"


Now, if you tires grip real well, then weird sounds may be made, but usually not during rain or snow when the pavement is slippery.

You may want to have the system checked out.

 

[PaulC]

I doubt that a wet paved road will be slippery enough to allow the tires to EASILY slip as required in 4HI or 4LO. IMHO, that would explain what you were experiencing.

I don't know what safety advantages shifting to 4HI in the rain would provide. Your truck won't stick to the road any more effectively, and the A4WD position would feed power to the front wheels if you attempted to break traction by mashing the accelerator at low speeds on a tight turn. I've never used 4HI in the rain.

 

[Fred69]

I would say unless you are on a flooded street 4 Hi is a great way to find out just how much your local dealer will charge to replace your exploded drivetrain. A4wd I think would be more appropriate, however as stated above unless you push the pedal thru the firewall which is unsafe on slippery roads anyway. You also should NEVER CROSS ANY WATER UNLESS YOU ARE ABSOLUTELY SURE OF IT"S DEPTH< AND OR SPEED. Many people have died attempting to negeotate a water covered road... I cannot recall using 4-Hi except in 8" of snow or more here in Michigan... Ocassionally on slippery muddy hills, and roads. Then again I was only going 25 mph tops and was passing everyone including the County plow trucks.