Crossing the rockies for the first time, advice?

[mptjelgin]

On 8/19/2020 at 5:01 PM, amarie1 said:

Also, from what I understand, I either use Tow/Haul mode, or I manually downshift/upshift, not both. So I kept my hands off the shifter, left it in D the whole time. Correct? Or not.

AM

 

I hadn't seen this before, but want to let you know that you can use Tow/Haul mode and manually shift if you choose to do so. One does not cancel out the other. Again, my opinion is that you are doing just fine that way you are driving it now. As I stated earlier I don't keep the cruise on for steep uphill grades because I am fine losing a few mph going uphill. I hate it when the truck downshifts and revs up one more time when I can see the crest of the hill just ahead and know that the climb is essentially finished. But it doesn't hurt anything but gas mileage. 

By all means try everything that has been mentioned here. But not on a steep mountain grade where things can get weird in a hurry. 

But what you did during the first part of your journey was just fine. You don't need to adopt an entirely different way of driving and start manually selecting gears. Simply not necessary. In my experience. Full-timing with my 2019 Ford Superduty...  

[mptjelgin]

1 hour ago, Kirk W said:

If it were me, I would try descending out of cruise and tow/haul at least once or twice, 

Taking it out of cruise and manually shifting is one thing, but taking it out of tow/haul is another. One of the features of tow/haul is keeping the torque converter locked so that engine braking is most effective. Overall, tow/haul uses shifting and torque converter strategies that reduce heat in the transmission. 

Turning off tow/haul will tell the truck that you are "free-wheeling" (for lack of a better term) down the hill, and may cause the torque converter to unlock. As you know, this reduces the effectiveness of engine braking and will add heat to the transmission fluid. Neither are positive.

AM - Leave it in tow/haul on descents, and frankly whenever you are driving. If you want to play around with shifting you can still do so in tow/haul mode. One does not preclude the other. 

 

 

[Kirk W]

AM, I sent you a private message.   😊

[amarie1]

Thank you everyone! It's much clearer to me now, after reading all of your well thought-out and details posts.

On 8/24/2020 at 12:12 PM, mptjelgin said:

My only problem with the tow/haul mode on a downhill grade as that the vehicle will "hold on" to the lower gear much  longer than necessary, and you'll find the engine turning unnecessarily fast on the flat ground at the bottom. It will come out of it eventually, but I sometimes will turn tow/hall off and then back on to "reset" it. 

Interesting. I will try the off/on in that case.

I did notice that when I needed to exit and slow down quickly to 30 or 20 mph, the engine felt strange and made some strange noises as I pressed on the brake firmly for a while. Like it didn't believe I really wanted to go that slow, or it was coming out of a tow/haul fever dream. Disconcerting

AM

[Al F]

1 hour ago, amarie1 said:

Thank you everyone! It's much clearer to me now, after reading all of your well thought-out and details posts.

Interesting. I will try the off/on in that case.

I did notice that when I needed to exit and slow down quickly to 30 or 20 mph, the engine felt strange and made some strange noises as I pressed on the brake firmly for a while. Like it didn't believe I really wanted to go that slow, or it was coming out of a tow/haul fever dream. Disconcerting

AM

If your tow/haul was turned on it may have been the computer downshifting the transmission to use engine braking to slow down the RV.  

The next time you have a chance try the quick slow down and keep an eye on the RPM's.  If the RPMs are jumping up when you hear the noise, the tow/haul mode is using engine braking to help slow you down.  

This is where starting off manually selecting 1 and going up to 3000-4000 RPM and then going to 2nd and then 4th and finally to D and listening to the transmission shifting and keeping track of the shifts, i.e. 1, 2, 3, 4, 5, 6.  This gives you a feel for what kind of engine sounds you can expect to hear. 

Also, sometime, start from a stop with the gear shift in D and then press the accelerator all the way to the floor and keep it there until you get to about 65mph.  (I don't mean for you to stomp on the accelerator, just take about 2-3 seconds to go from rest to all the way down)  Keep an eye on the RPMs  and also count the shifts.  This gives you a feel for the sounds and feel of the engine.  I would expect for you to see the shifts happening at some where between 3000 and 4000 RPM.   

All this is to help you become accustom to the sounds of the engine when it shifts at higher RPMs.  

[Al F]

On 8/22/2020 at 11:33 AM, amarie1 said:

As I posted in another thread here, I survived! lol I made it ... I'm in Oakland now, arrived yesterday afternoon. Thank you all so much for your help.

I ended up not shifting to anything since I didn't know what I was doing. I let Tow/Haul do its job. I turned off cruise control on the uphills and just used manual acceleration. 

At one point, the Check Engine light started flashing on the dash board display, toward the beginning of the trip. It flashed for about a minute, which was a long time to me! lol I'll bring it to a service station but I'm curious if anyone had heard of this. I hadn't just filled up my tank (which I know sometimes a loose gas cap can cause that). I had just heard the engine rev up as it doing its thing going up the first incline. I don't know if that was coincidence. It never did it again, and I was paranoid about it. 

Thanks for all your help! I will learn more about downshifting while I'm here 😉  so I know better when I return to Chicago in a couple/three weeks.

AM

 

About the engine rev'ing up as you started the first incline.  

If you had the cruise control on that was most likely just the cruise control down shifting the transmission to try to keep your speed up.   A quick glance at the RPM gauge would confirm this if/when it happens again. 

If you were manually using the accelerator to keep you speed up, you were probably just slowly pressing on the accelerator to keep your speed up, until the computer sensed that it needed to down shift to try to keep your speed up.   Kind of like when in a car and you go to pass another car on a 2 lane hwy and you press the accelerator hard causing the transmission to down shift to help you speed up to pass the other car.

I helps to remember your are basically driving a large truck that is heavily loaded, so there will be times that the transmission will down shift and cause the engine RPMs to jump up making an unexpected noise.   Also the engine is just to the right and below your right foot, so when the RPMs change suddenly you will hear it.  In a car the engine is farther in front of you, much smaller, and the sound proofing between the driver and the engine is much better.  

Edited August 25, 2020 by Al F

[mptjelgin]

2 hours ago, amarie1 said:

Thank you everyone! It's much clearer to me now, after reading all of your well thought-out and details posts.

Interesting. I will try the off/on in that case.

I did notice that when I needed to exit and slow down quickly to 30 or 20 mph, the engine felt strange and made some strange noises as I pressed on the brake firmly for a while. Like it didn't believe I really wanted to go that slow, or it was coming out of a tow/haul fever dream. Disconcerting

AM

As Al said, with tow/haul on the transmission will downshift quickly (with engine rpm jumping up) to "help" you slow down, even on flat ground at low speeds. What you are hearing and feeling is the truck doing just that.  It helps to save the brakes on the RV, but if you don't like it you can turn/off tow haul in those situations. However I always leave mine on and have gotten used to it.  Also, I don't want to forget to turn tow/haul back on when I might really need it!  It sounds like you are getting used to the sounds and feelings of the RV doing exactly what it is designed to do. 

[Kirk W]

1 hour ago, Al F said:

The next time you have a chance try the quick slow down and keep an eye on the RPM's.  If the RPMs are jumping up when you hear the noise, the tow/haul mode is using engine braking to help slow you down.  

Some excellent advice.