going up a mountain shifting?

My preferred technique for coming down a steep, long grade is to find the gear and jake brake setting that will hold without having to snub brake, nice and slow; and then roll down the window, light a cigarette, and enjoy the action as the macho heads go screaming by me.

Learning to downshift on a downgrade is an ESSENTIAL tool in your "technique toolbox". I heartily disagree with the advise that you should "never downshift on a downgrade". Each time down a given grade can require a different gear and jake setting for optimal control. It will depend on weight of the load, road conditions, and traffic conditions. When I need to downshift on a downgrade I smoothly brake until rpm's are about 700, disengage the jake, make the shift at about 1200 rpm's (with room to "follow" it up to 1500 rpm if I miss it and I start picking up speed), reengage the jake, then let off the throttle and see if the jake will hold. Repeat as necessary.

Going uphill I disengage cruise and jake. I'll usually make the downshift around 1200 rpm with these modern trucks, knowing I'll be slowing quicker going uphill, catching the next gear down at about 1500 rpm without being all in a big hurry to get into that gear... in other words I maintain my normal rhythm of shifting. If the grade gets REALLY steep I'll drop two gears.

 

Going up is no problem at all. That's the best time for me. I love letting the engine work for me. I'd get too tired if it was the other way around. I never run the tack to peg, keep good care of the truck and it will pay you back. They are made for high torque low rpm (lower than a car) so let them work. When climbing you'll start to drop in RPM, let it go down far enough where the power keeps kicking in. You'll be right on when pulling and the RPM'S stay the same. When going down forget that old saying go down in the same gear you came up. Engines today are different and so are the roads. If you're loaded and have no idea on how fast to go, if it's 6° down I wouldn't go over 30mph until you know. You might even go slower if you do not feel right. But above all make sure your brakes are working 100% and take no one's word for it.

 

Where'd you get your facts. I'd like to read them myself. I I've been in an automatic on and off for the past year. In my 8 years I've never had an accident that was my fault. Only been in one bat at fault accident. Guess that means I don't know how to shift. Personally I like the automatic. Cruise control stays on going up the grades and will downshift at 1100 rpms. When going down a grade I switch to manual mode and drop it to 9th or 8th, jakes on and never touch the brakes. I haul liquid so when I'm loaded I'm always real close to 80K lbs.

 

This thread has been hijacked. The question was why the rpms shoot up when he clutches to downshift.

 

True that and it would be good to hear back from the OP. Only time that ever happened to me is when I forgot to disengage cruise control and started to shift by double clutching. There's a reason why the manual warns against that maneuver.

 

Please send a link to that warning

 

My truck came with a manual. I'm not in the truck right now, but do recall reading that attempting to shift with cruise control engaged can "result in serious engine damage", or something to that effect. The one time I forgot to disengage the rpm's roared right up to 2000 and held there until I disengaged the cruise.

You can download a pdf of your truck online if you don't have a hard copy.

 

Im sure the op has already solved the problem of engine revving up when shifting by now?LOL Hopefully anyway? This is a long thread.

 

[QUOTE="semi" retired;4006443]Hey 70s_driver, once when coming back from Fla. I took 41 down the backside of Monteagle, 2 lane, that scared me in a car![/QUOTE]

LOL yea I bet, imagine it in a truck and to think guys in my dads generation, that's the only way they had over it. Ive went down it a few times but they completed 24 shortly after I started driving, which the longest trailer they had then was a 40 foot. My dad started driving in 39. Boy he had all kinds of stories to tell! running up 127 wasn't a lot of fun either. It was still 2 lane in them days. Matter of a fact, some of it is still 2 lane when you get up close to KY. I noticed the last time I went over Monteagle, the old truckstops are gone. Theres a Conoco or something where Monteagle Truck Plaza used to be. The other one was torn down completely, where they had that trucker wall of fame.