Driving an automatic on icy roads and taking off on hills?

Without the fan, a boundary layer of warmer air is forming above the cold floor. If you had a way to directly measure the floor with a contact thermometer, it would read the colder temp even without the fan.

 

Now try it outside with something that has been sitting outside long enough to be the ambient temperature and see if it reads colder because the actual wind is blowing.

 

To warn stupid people that is getting close to freezing.

 

From my training the missing part is the differentials don’t apply all the power from the engine brake the same to each set of drive tires. If one has less traction or to much engine braking power is applied that set of drives will lose traction and the engine brake will slow them down. Now that set of drive tires is spinning slower then the rest. You cannot let that continue so you now have to turn the engine brake off and wait till that set of drive tires get traction and start rolling the same speed as all the others. Some driver might even accelerate a little but you could give to much power and now you have a power spin and you have wait for the tires to slow down. You are losing or wasting all this time trying to get tires rolling again to keep control of the truck.

If the tractor starts to slide you probably won’t be able to stop it because you are letting the trailer push you down the hill. When the trailer is pushing the tractor the trailer is in control. When the tractor is pulling the trailer (you) the tractor is in control.

The trailer will always want go straight and the tractor at 60,000 lbs vs the tractor at 20,000 lbs. The trailer will win every time and it will keep going straight and push the tractor out of the way. The tractor is hooked to trailer so tractor will jackknife.

If you’re going downhill with engine brake on. The trailer is pushing the tractor down the hill. If you turn to go around a curve in the road. What does the trailer want to do ? It wants to keep going straight and it can just push the tractor out of the way and keep going straight off the road into the ditch. Since tractor is hooked to trailer you are going along for the ride. The tractor will jackknife and you have nothing to stop it from happening.

If you apply all the brakes then the trailer is not pushing the tractor. The trailer brakes are holding the trailer back behind your tractor. If the trailer brakes lose traction and trailer starts to slide and come around. All you do is take your foot off the brake and let the tires get traction and rolling and the trailer should go back behind tractor.

If that don’t not work and the jackknife continues all you do is now apply power and pull the trailer downhill and pull the trailer back behind your tractor. Because when you pull the trailer you are in control. So you have another chance to stop the jackknife. When the trailer is back behind your tractor you apply the brakes again to slow down.

The way I was trained letting the trailer push you down hill is really bad idea and you are just setting yourself up for an accident. Why are drivers using the engine brake in snow and ice ? To save $1 of wear on the brakes vs a possible jackknife accident that will cost who know what $50,000+

The engine brake is only designed to help save wear on the brakes or to keep them cool.

 

I remember thinking the same way as you when I was a flatlander who moved to Western Montana back in 1999. But then I kept my mouth shut and listened to what the old timers were saying and watching what they were teaching me in regards to driving in the mountains. If you don’t have experience for the given situations you’re not going to understand it and you’re not going to convince any of us that have been there that the way you were trained is superior to real world experience.

Most Sunday’s for the better part of 10 years my week started out with a trip over Lost Trail because we weren’t allowed to run the extra miles to go around on the interstate. And unless the road was physically closed it was expected that we get over the hill and go to Utah. I can’t recall a single time ever riding my brakes for 9 miles trying to hold back 105k.

You learn to read the surface of the road and watch the temperature and look at other people’s tire tracks that are in front of you.

 

Wind chill is affect the transfer of heat so at say 60mph the wicking away of the heat is faster so whatever warmth there was can't keep up.

 

Harpster is a short but fun one!

 

I appreciate the effort and thought that you have put into this, and we probably won't change your mind. Here are a few thoughts though:

• If, when decending down a hill with the Jake on and the power divider NOT locked in, one wheel end slips, I apply a bit of trailer brake and blip the throttle to get it rolling again. Alternatively I will apply a bit of brake pressure with my left foot while giving a touch of throttle with my right. The truck is still tracking straight because 3 out of 4 wheel ends on the drives never slipped. I do not use lockers going downhill.
• If you are grossing 80K the tractor will be at 46k and the trailer 34k, not the 20/60 that you suggested.
• I have started a slip or jacknife numerous times and have always been able to control it, but then again I learned to drive by doing cookies in the high school parking lot, and intentionally losing control to learn how to react. It is not all that different with a truck. If you panic and over-react you are in trouble.

• We aren't as concerned about saving $1 worth of brake wear as we are coming down the mountain safely.

Anyway, to each his own and do what works for you, and I for one appreciate the discussion. We will probably have to agree to disagree. By the way, I am often at 130K or more on 7 axles.