What are the safe limits of using 4WD?

[Haulin' 8.1]

As I've always understood using 4wd on the pavement is hard on the driveline. Is this still true with these newer trucks? We don't get much snow and ice in south east Texas but a lot rain during the cooler seasons. Is it ok to use 4 high when it's pouring out on the roads or should it be avoided. Is there a maximum recommended speed while in 4wd?

 

Any advice in this area will be appreciated, this is the first 4x4 I've ever owned. It's got the push button transfer case.

 

Thanks,

Vernon

[johnnyo4]

You shouldn't use 4-wheel drive on hard dry pavement. Even with the new models. It has to do with the spin rates of the front and back wheels as you go into turns. They are different and puts stress on the drive train. Additionally your maneuverability is worse.

 

However on loose and slippery pavements - snow, ice sand it works.

 

A good read on 4-wheel drive:

http://4wheeldrive.about.com/cs/offroading...aa021203a_3.htm

[ManyCamaroz]

Do you have a problem with slipping and sliding in the rain or wet roads?

[Silverado4x4]

Never use 4wd on dry pavement,I only put it in 4wd on dry pavement if I dont use it for a couple of months in the summer just to sling some oil around in the front drivetrain but ONLY going in a straight line for about 5 to 600 ft. If you make a sharp turn in 4wd on dry pavement you are likely to snap a cv joint or front axle because of binding.

[Haulin' 8.1]

Thanks for the input guys, that's what I thought I just wanted to be sure. It's not that I have big problems on wet roads but today my girlfriend, who uses a Sunbird beater to deliver mail, got off in the ditch and sunk the car. So she called me up to come pull her out. I was trying to get there ASAP and was thinking how nice it would be to have the confidence of AWD when taking wet corners fast and to be able to take off easier with the 496 on wet pavement. So I used the 4WD to pull her out then just as I sent her on her way and was climbing back into the truck some other people pulled up behind me and I was blocking the road. I felt like I needed move quickly so while on the pavement in 4WD I had to drive about half a block to find a driveway big enough to swing into and disenguage the transfer case. I then wondered if it was causing any extra wear and if I should have just made them wait while it switched back. I don't think it was a big deal but would like some experienced opinions.

 

I remember about ten+ years ago there were some kits availiable that placed a vicious coupling on the front output shaft of the case like the SS or similar. The advertisments claimed you could then leave 4WD enguaged at all times to have the advantages of AWD without the binding. I would imagine that it would reduce the true off road capabilitys though. I don't know if they were junk, or just unpopular but I haven't seen anything like that since. Anybody know if they're still around or if they work?

 

Vernon

[Butch 02 Denali]

Vernon,

 

You said you had push button 4wd, do you have an Autotrac button? That CAN be used on dry roads, but I don't know why you'd want to.

[Peter_C]

You can also shift on the fly, unless you were in 4 low, then you do need to be stopped.

 

If I broke a CV joint on dry pavement turning a corner I would be pissed! I have taken my trucks places that require 4 low and have had the truck on two and three wheels many a time. I do not expect it to be as tough as my highly modified rock crawler, but come on it is a 3/4 ton.

[Chev8.1]

You had to use 4x4 to pull out a sunbird?? come on. ..

 

Honest, autotrac is not offer a Hd series, in pinch, can be use only in straight line. But as I scan the various other HD forums, Good use is drag racing and truck pulling, and the current GM HD drivetrain has proved to be stout and very strong. Again CV joints will not fail if they are keep in thier operating range. Meaning angles from t-bars being cranked, but usually only break under compeition use.

[Truckman031]

You don't stop to put the truck in 4 Low. To engage it, put the tranny in neutral rolling at 3 to 5 mph, same thing to change it back to 2 Hi or 4 Hi.

[Kgry]

Yeah actually you're not supposed to stop to engage 4Lo. It's a pretty hard shift if you're not rolling in neutral.

[Ranger354]

Vernon,

 

Almost always shift while moving at very minimal speed. Even when going into or out of 4Low. Like mentioned above it gives the transfer case the option when to shift instead of just craming it into of out of gear. The roads around Magnolia could get slippery when wet, but I don't think it would be a good idea to place your truck in 4wd unless you are on some of the county roads that have gravel on them.

 

That sure is pretty country up there. My brother has a cabin on the edge of the National Forest. There used to be alot more gravel roads in that area then there are now. Went to Planterville last Nov for the Festival.

[Haulin' 8.1]

This post seems to be popular so I'd like to add an update. Thanks to all posters for your help

 

The day after I made this post and got to read the first round of responces a customer dropped off a '99 Z71 for an intermitant miss at high speeds. It was still raining hard, still is in fact. Imediately I noticed the "Auto 4wd" button. So I tried it out, it worked exactly like I would have hoped. The truck could accelerate at WOT from a dead stop on wet pavement without any wheel spin. It would pull itself through a curve that would have generated slippage without the 4wd. The shift in and out was inperceptable to me. I wish this was on my HD.

 

So I started thinking about how similar that trucks driveline was to mine and decided to try it myself on my truck manually (using 4HI only of course). Heck, some of these guys drag race in 4WD. I found that having my truck in 4HI allowed it to drive exactly as the Z71 did in the rain. It will roll at the speed limit just the same, will coast just the same. The only time I noted any perceptable driveline stuff was when turning on pavement at full steering angle, and then it wasn't nearly as bad as the Dodge Ram short bed I drove a week prior, if I hadn't been looking for it I might not have noticed it. It could just be how the tires feel when pulling at angles for what it's worth. After getting used to it as a drivable option I tried shifting in and out of 2HI and 4HI on the move, always putting the transmission in nuetral as indicated by the diagram on the push button panel. The truck will shift in and out of 4HI at any speed without issue as long as you keep your foot off the throttle. This morning I thought I should blip the trottle when putting it back into drive at 55 to match the impending grab but the engine control was doing it automatically for me so I actually over revved it and had a clunk.

 

I should note that my truck doesn't have locking differentials.

 

I don't know the long term effects, but if I break anything I'll just fix it and count it as a lesson learned, wouldn't be the tenth time. I don't plan on driving around in 4HI all the time but it's nice to know it can be engaged when wanted without stopping or worry of instant damage. My main use would be pulling out into the busy traffic around my shop when it's wet without getting hit or burning the tires, then putting it back into 2HI once crusing speed is reached.

 

Does anyone know a good reason why you can't go as fast as you want in 4LO? I would have thought the guys with automatic overdrive trannies would drag in 4LO for the added acceleration.

 

Vernon

[496 CUBIC INCHES]

You don't stop to put the truck in 4 Low.  To engage it, put the tranny in neutral rolling at 3 to 5 mph, same thing to change it back to 2 Hi or 4 Hi.

 

<{POST_SNAPBACK}>

 

 

 

My truck WILL NOT go into or out of 4lo if I'm moving. I have to be completly stopped in neutral for it to engage. I've tried the rolling 4lo thing and the light on the 4lo button just blinks,and I stay in 4hi.

[Daubs]

My $0.02

 

I've owned the following 4x4's -- 1982 K-10, 1987 K-20HD, 1999 Z-71, 2001 Z-71 and currently have 2004 2500HD (wife has 03 Z-71 Burban). That said...

 

I'm a big fan of the AutoTrac 4x4 system. It's perfectly safe on dry, wet, slick, snowy pavement. Sends majority of power to rear wheels until system detects slip, then sends power to the front. If you mess around long enough you can feel the power going to the front wheels when driving on snow packed roads. Really d**n cool. I almost purchased the 2500 CC with the 6.0 mainly due to the AutoTrac system...but the 8.1/Allison won out, so that's what I have. I do miss the AutoTrac.

 

As far as driving in 4x4 on dry pavement...well I was hunting last week and driving on a muddy road in four wheel drive. Pulled on to the interstate and forgot about being in 4x4. Truck handled fine, but felt a little funny coming down the off ramp. Then I realized it was in 4x4. I switched back. Yes, I do believe you put undue stress on the drivetrain when in 4x4 on dry pavement, but I don't think you are going to snap a CV joint. Folks, these trucks are designed to take much more abuse than the average person will dish out. And to see those guys with D-max running hot chip setups and doing 1/4 mile in four wheel drive...well, you tell me how much the drivetrain can handle! Blasting down the quarter mile in a 6000 pound truck and clocking 11 second runs...Amazing!

 

No, I won't make it a habbit to drive in 4x4 on dry pavement. But in a pinch (like pulling someone out of a ditch) it's fine.

 

Just my opinion...I could be wrong.

[496 CUBIC INCHES]

No, I won't make it a habbit to drive in 4x4 on dry pavement.  But in a pinch (like pulling someone out of a ditch) it's fine.

 

 

 

<{POST_SNAPBACK}>

 

 

 

Last month my Brother had to back my truck across the sand at the beach to get my boat on the trailer. He put it in 4hi to leave the sand and forgot to take it out of 4hi. I didn't realize it until we made it home. I drove about 10 miles at 35mph on the paved backroads to my house. Not until I went to back my boat into the garage did I realize it was in 4hi,some slight binding made me say WTF? I looked at the light and realized I was in 4hi.

 

I can't believe that little jaunt in 4hi hurt anything on my truck. If thats all it takes to puke the 4x4 GM needs to beef it up a bit.

 

Like the other guy said,don't make it a habit to run around on paved roads in 4x4 and you'll be fine.