Engaged 4wd High speed

[HK 3]

I feel like the north end of a horse going south with this question. I drove approximately 38 miles with my 4wd high engaged on the highway. I was traveling at speeds of 75 to 80 miles per hour for about 30 minutes. Have I cooked my front transfer case? I realized I was in 4wd when I turned into my driveway and felt the resistance in the steering wheel and the "crimp" on the front tires. When I parked, I crawled under the front bumper and the front transfer case was too hot to touch and leave your hand on. Should I have the transfer case oil immediately changed? What potential damage may be the result of my stupidity? Other than a very very slight "hum" in the cab on throttle increase at 70 to 75 mph, I did not notice any difference in the way the Duramax drove while engaged in 4wd High. I wish one of my boys would have done this and then I would simply drop kick him into the next county. Unfortunately, the alternative may be to just take me out in the corn field and shoot me! Any thoughts or suggestions would be appreciated.

[DmaxMaverick]

Don't sweat it, HK.

I've had 4 X 4 on all my vehicles since I started driving and have done that on all of them at one time or another, including my '01. I doubt that anyone here that has ever used 4 X 4 can honestly say they haven't done it.

Driving at high speeds, reletively straight, doesn't add too much additional stress on the system. If you have front/rear tires of different size, or make a lot of turns on pavement (like city driving), the story would be different.

Just consider it broke in and change that oil. Adding synthetic oil will minimize any damage, if you should do it again in the future. Even under correct 4 X 4, or 4 X 2 use, the transfer case will get hot. Maybe a little more under your circumstances.

Cheers

[pushpole]

I've done it too. I even got out and put my hand on the tranfer case and differential to see if it was overheated--nothing abnormal. I'm waiting for the heads-up display warning that says Hey! you are travelling 70 mph do you really want to be in 4WD?....maybe next year.

[schnier]

I have done this for about 15 miles also at 75 mph pulling 9,000 lbs. I now have 37,000 miles on it and it works fine. Mine did spill trans fluid out the vent hose from the transfer case and all over the bottom of the truck. I thought I blew it up. Well that was last year and I cleaned the bottom of the truck checked transfer fluid and added about 6 ounces of fluid and all is well .Don't sweat it theses things are pretty tough.

[Mudflap]

Normally the only thing that will happen is that your tires will wear funny. There is some strain on the drive train but nothing it can't handle. However, if you are towing heavy with equalizers it could be a different story. Several years ago, we had a '93 Chevy gasser with 18K on it pulling a 30' Terry. We stopped at a campground in Indiana for the night and I had to use 4WD just to maneuver and I forgot to take it back out. So we put in the next 100 miles or so on I-70 in 4WD on a very hot day when the front end grenaded. I thought I had lost the engine. Had a hard time getting the 4WD to disengage so we could drive the truck. When we got home Chevy replaced the front end under WARRANTY! They said it never should have happened no matter how long I had it engaged.

[HK 3]

Many thanks for the posts from DmaxMaverick, Mudflap, Pushpole, & Schnier. Guess I'm not the only one to have done this. I will take the shell our of the shotgun and fill the hole I dug out in the corn field.

[conradv]

The Ford boys aren't immune either - my brother forgot and drove about 125 miles with it in 4 wheel - in his Powerstroke.