Did something stupid yesterday, and hope I didn't do any damage.:eek:

I had the truck in 4 hi while in a back pasture. Got on the main road and then the highway and forgot that I had it in 4-hi. Got up to 60-65mph and heard a pretty loud whine. The road was being worked on so I thought it was just from the road . This went on for probably about 3 miles before I realized I had it in 4 hi. :( Talk about feeling stupid.

One thing that makes me feel a little better is that I put transcynd in the transfer case about a month ago. I am still wanting to put a synthetic in the front diff, maybe now would be a good time to do it.

Just want some opinions if ya'll think I did any appreciable damage.

Also, forgot to mention that I was towing a 24 ft. flatbed with maybe a ton of hay.

thanks

You have nothing to worry about at all. I wouldn't drive around for 100's of miles in 4hi but the little 3 miles you did is nothing. Even if you drove 30 miles I still wouldn't worry about it. These are tough transfer cases.

Ive been in 4hi for about a month now because all we drive on here is ice. Well snow sometimes but ice most of the time. I was also in 4hi most of last winter too. All of my high way miles this winter have been in 4hi while pulling the 4wheelers out to ride I usually have two in the bed and two on the trailer.

Thanks for the replies. The loud whining noise is what got me worried. And seems like I read somewhere not to exceed 45mph in 4 hi. But I figured there had to be a large safety margin as well.

This is my first 4-wheel drive and its great!!!!

):h ):h ):h ):h ):h ......not laughing at you Wick, just the thought of the ABUSE I've put mine through compared to what your talking about! Seriously, these transfer cases are tough as nails.....you will likely hurt a lot of other stuff before you damage t-case. BTW...general calls for "Auto-trak" fluid in t-case and synthetic 75/90 for diff. Tran-send is for Allisson.(but Dextron III is plenty good.) Take care, Ed.

No Autotraks in the Duramax. It takes Dexron III or the synthetic equivalent. Later! Frank

There are plenty more to worry about other than the transfer case, like tie rods, front bearings, or the whole front end before worring about the transfer case.
I personly like to drive in 2 wheel most of the time unless I am towing things on the highway in the winter time.
The only time 4 wheel could be a problem is if you are making a lot of sharp turns on dry pavement at above parking lot speeds.
If I remember correctly the owners manual said to keep it below 45 mph during brake in periods.

IIRC, there is already synthetic fluid in both the diffs, factory

I did this while towing last year. Had it in 4hi to manuever my trailer in a wet grassy field, and didn't realize I had left it in 4hi til about 150 highway miles later. Doh! No whine, nothing. Just noticed the light on. Everything has been fine since then.

I read this thread last night and thought to myself "How can you not feel that it's in 4WD?". Well, there's egg on my face! With all the snow yesterday I had it in 4WD to back into the garage. Forgot to take it out and drove for about 3 miles this AM at highway speeds until I realized it was on.

IIRC my wife's '01 Yukon goes out ot 4WD automatically once the ignition is turned off, but I could be wrong. I'll have to check and see.

Rob

I wouldn't worry about it either. My wife on her Trailblazer leaves it in Auto 4 almost nonstop(she turns it on and forgets to turn it off). I've done it myself a few times on my truck as well but in short spurts as you did.

In essence general consensus seems that the drivetrain seems to be pretty durable.

The Jeep Grands have a nice set up on there All time four wheel system. I am not sure if it is the same as the new All Time 4 Wheel system on the GM vehicles.
In the All Time 4 Wheel Drive system on the GM it is has a clutch set up in it. When the front tires start to spin it will ingage the front axle and put power to the front.

And seems like I read somewhere not to exceed 45mph in 4 hi.

I'm very sure the transfer case can handle up to 112 mph in 4wd on dry pavement.

When I went home to Colorado for thanksgiving, there was 6 inces on the ground of fresh snow, the roads were still covered so I put it 4 hi and drove south to I-70 it was like 150 miles, roads still packed with snow and ice and I had a long way to go so I left it in so I could drive at speeds around 55 to 65 safely, finally reached the Interstate so I was like great it looks clear, so I hit button and took er out of 4, Im cruising along, the roads are wet but clear, and then I see massive carnage, the ditches were full of destroyed vehichles, all rolled several times, so Im like hmmm..back in 4 we go. It was solid black ice, so the moral of this story I had my truck in four for about 200 miles at speeds around 60, didnt even think twice. The way I look at it, Im a heck of alot better off than everyone that totalled their vehichles. Im sure it didnt hurt a thing.

I read this thread last night and thought to myself "How can you not feel that it's in 4WD?". For me it depends on how loud I have the radio!http://www.dieselplace.com/forum/images/smilies/hihi.gif

I had my truck in 4 hi today at about 60-65 and heard a howling noise. Is this the t-case or front end.

And seems like I read somewhere not to exceed 45mph in 4 hi. I think you aren't supposed to try to switch to 4WD at speeds over 45, that's probably what you are remembering.

GM trucks howl more in 4x4 on the highway than any of the solid axle type trucks I have owned (had a few). I asked about it on my original test ride (then drove 2 others) and the sales guy was right, they all do it. thanx geo.

From the '05 Owner's Manual:

Shifting from 2HI to 4HI

Press and release the 4HI switch. This can be done at any speed, and the front axle will lock automatically with some delay.

Same wording for going from 4HI to 2HI. Mine whines a fair amount at speed, much more than my '99 Ram did. As long as your going in a straight line, and the differences in your tire circumference are negligable, your not going to hurt anything on dry pavement, IMHO.

Just for the record When I switch in either 4hi or 2hi I let off the throtle to allow the gears to switch tso they are not under a load. I stay off the throtle a little longer when in the cold times of year.

GM trucks howl more in 4x4 on the highway than any of the solid axle type trucks I have owned (had a few). I asked about it on my original test ride (then drove 2 others) and the sales guy was right, they all do it. thanx geo.
Tell me about it I could hear mine howling over the radio.:eek:

I'm very sure the transfer case can handle up to 112 mph in 4wd on dry pavement.
:ro)

I have driven in 4wd for many more miles than I care to admit at 75-80 mph on icy highways. Since I then I have added mud terrains and 600 lbs. of sand and don't have a need for it on the highway, but I doubt that there is any harm done.

Mine doesn't howl loud at all, I don't know why. I know it is locking in too. hmmmmmm.

Mama JJ drove in 4x4 for 150 miles at 70mph towing our 5ver. The only thing she noticed was the truck sure seemed to pull the hills with ease. ):h Your truck should be fine. Might change out the fluids though. JJ :)

Thanks for all the responses. Since that happened , we had 12 inches of snow. Although I didn't have to drive in it, I would feel comfortable leaving it in 4-hi. But probably won't need any time soon since the last time Victoria had 12 inches of snow was in 1895.):h):h):h):h):h

You really shouldn't have said that! JJ):h

Thanks for all the responses. Since that happened , we had 12 inches of snow. Although I didn't have to drive in it, I would feel comfortable leaving it in 4-hi. But probably won't need any time soon since the last time Victoria had 12 inches of snow was in 1895.):h):h):h):h):h