Serrano Mountain/Hill driving

[bodycoach2]

We've had our Serrano for a 1 1/2 years, but have yet to take it in the Mountains. We live in Florida, and are inexperienced with driving/shifting on hills. Those of you Serrano owners, could you give us lowlanders some information and advice on how you drive your Serrano through the mountains.

[edgray]

Originally Posted by bodycoach2

We've had our Serrano for a 1 1/2 years, but have yet to take it in the Mountains. We live in Florida, and are inexperienced with driving/shifting on hills. Those of you Serrano owners, could you give us lowlanders some information and advice on how you drive your Serrano through the mountains.

Since you've not gotten any replies from other Serrano owners, I hope a fellow Workhorse owner's opinions will suffice. The engine/tranny combo are similar enough, and the brakes are the same, whether gas or diesel.

1. don't try to use the CC in hilly terrain, it WILL cause the motor to rev to higher RPMs than you would with you foot. The CC only knows to keep demanding "more" throttle to reach the set speed. Using the pedal, try to gain RPMs and speed BEFORE beginning the climb, and learn to meter the throttle to maintain RPMs without unnecessary downshifts. You may lose some speed on a steep hill, but so will most other large vehicles-just stay to the right and let the faster cars go by.

2. ALWAYS downshift to a lower gear BEFORE you begin a downgrade. The TCM/ ECM interface won't let you downshift after you gained too much downhill momentum "if" that will cause over-rev and damage the engine, so you will be required to apply the service brakes. Too much braking can cause over-heating and brake "fade"- so just DOWNSHIFT at the hilltop and let the tranny and motor retard your speed.

3. IF you NEED to apply the brakes to augment the engine/tranny resistance, then apply the brakes very firmly for brief time periods to kill the excess speed. Don't "ride" your brakes with light pressure on the pedal for long time periods- they will get too hot. Press hard, release, repeat as necessary.

[anotherone]

Originally Posted by edgray

Since you've not gotten any replies from other Serrano owners, I hope a fellow Workhorse owner's opinions will suffice. The engine/tranny combo are similar enough, and the brakes are the same, whether gas or diesel.

1. don't try to use the CC in hilly terrain, it WILL cause the motor to rev to higher RPMs than you would with you foot. The CC only knows to keep demanding "more" throttle to reach the set speed. Using the pedal, try to gain RPMs and speed BEFORE beginning the climb, and learn to meter the throttle to maintain RPMs without unnecessary downshifts. You may lose some speed on a steep hill, but so will most other large vehicles-just stay to the right and let the faster cars go by.

2. ALWAYS downshift to a lower gear BEFORE you begin a downgrade. The TCM/ ECM interface won't let you downshift after you gained too much downhill momentum "if" that will cause over-rev and damage the engine, so you will be required to apply the service brakes. Too much braking can cause over-heating and brake "fade"- so just DOWNSHIFT at the hilltop and let the tranny and motor retard your speed.

3. IF you NEED to apply the brakes to augment the engine/tranny resistance, then apply the brakes very firmly for brief time periods to kill the excess speed. Don't "ride" your brakes with light pressure on the pedal for long time periods- they will get too hot. Press hard, release, repeat as necessary.

I was reluctant to try to advise someone how to drive ; probably like most who read this but you hit the nail on the head. Some things are hard to put into words. Good job and you have courage. I agree 1000 percent.

[Steve N Sal]

"edgray", EXCELLENT set of instructions.

[bodycoach2]

Originally Posted by edgray

Since you've not gotten any replies from other Serrano owners, I hope a fellow Workhorse owner's opinions will suffice. The engine/tranny combo are similar enough, and the brakes are the same, whether gas or diesel.

1. don't try to use the CC in hilly terrain, it WILL cause the motor to rev to higher RPMs than you would with you foot. The CC only knows to keep demanding "more" throttle to reach the set speed. Using the pedal, try to gain RPMs and speed BEFORE beginning the climb, and learn to meter the throttle to maintain RPMs without unnecessary downshifts. You may lose some speed on a steep hill, but so will most other large vehicles-just stay to the right and let the faster cars go by.

2. ALWAYS downshift to a lower gear BEFORE you begin a downgrade. The TCM/ ECM interface won't let you downshift after you gained too much downhill momentum "if" that will cause over-rev and damage the engine, so you will be required to apply the service brakes. Too much braking can cause over-heating and brake "fade"- so just DOWNSHIFT at the hilltop and let the tranny and motor retard your speed.

3. IF you NEED to apply the brakes to augment the engine/tranny resistance, then apply the brakes very firmly for brief time periods to kill the excess speed. Don't "ride" your brakes with light pressure on the pedal for long time periods- they will get too hot. Press hard, release, repeat as necessary.

Thanks for the response. What does 'CC' mean?

[anotherone]

Hey neighbor , we have a serrano! The advice already given is spot on so no need to duplicate. The overdrive switch is actually a 3 way switch which I use for downshifting convenience. One position is off , then 1-5 , then 1-4 , of course on, goes thru 6th gear. CC means cruise control

[edgray]

Originally Posted by anotherone

Hey neighbor , we have a serrano! The advice already given is spot on so no need to duplicate. The overdrive switch is actually a 3 way switch which I use for downshifting convenience. One position is off , then 1-5 , then 1-4 , of course on, goes thru 6th gear. CC means cruise control

anotherone: You are correct about the three-position OD switch and the definition of CC, which I should have explained better in my post.

Please allow me to elaborate about the OD switch. The "off" position prevents the tranny from upshifting into 5th or 6th gear, both of which are "overdrive" ratios. The "middle" position allows 5th gear, but prevents going into 6th. The position fully opposite from "off" allows the tranny to operate in 5th AND to achieve 6th gear IF speed and load conditions are acceptable to the TCM. NOTE: Workhorse chassis that have 5 speed Allisons use an OD switch that is only two positions- "off" & "on". There is a light on the IP illiminates when these OD switches are "OFF", and the tach will be displaying higher RPMs as well.

I've talked to many owners who were not aware there even is a "middle" position. Its use can eliminate unnecessary shifting while travelling thru terrain that is only "slightly" hilly. There is really very little difference in the engine's RPMs between 5th and 6th, unlike the difference between 4th and 5th. Turning the OD switch OFF in hilly or mountain driving can save a lot of downshifting, and will not harm the motor even if driven in 4th all day long. Granted, that will likely burn more fuel, but 4th may be "better" for the tranny in the long run, by minimizing excessive shifting.

Does the WxxD chassis come with the Transmission Grade Brake (TGB) switch ? I did not include suggestions for its use in my original reply because I was not "certain" it is used on the diesel models. IF a TGB switch is present, having it in the "on" position will allow the driver to cause a downshift by pressing the brake pedal, rather than manually selecting a lower gear using the shift lever. This TGB funtion is both a saftey and convenience feature, but much confusion exists about "how" it works. A hint can be found in its middle name....normally it only works while desending a grade, so many "flatlanders" have never experienced its operation.

[TheArnolds]

Edgray: Thanks so much for the explaination, it cleared up a few things for me!

[bodycoach2]

Just got back from driving through the mountains of West Virginia, Virginia, Pennsylvania, and North Carolina. While I still don't have a functioning Cruise Control (going to work with Workhorse/Navistar on that in a week), I was VERY pleased with how the coach handled the mountains. NO problem going uphill at all. Passed 18 wheelers, gassers, and even a few F350's. Fuel consumption was around 'practical' 9 mpg (because of use of generator/air conditioner in the south, and a few overnights in parking lots with generator controlled by EC-30W autostart). Without the generator use, it was around 12 mpg.

Going the flatland, I kept the coach with in Overdrive mode with Econ turned on. When hills came up, I turned econ off. Going downhill, I'd put the overdrive in the 5th gear mode, and use the transmission/engine to keep me going downhill slowly. If I needed to go slower, I'd brake once and put it in overdrive off/4th gear mode. I only needed to go into 3rd gear mode once. I rarely needed to use the brakes going downhill.

The trip was almost stopped by a short in the junction box right before the generator connection. The Cummins guy showed me the problem. The other three were installed nicely, but that one was installed 'by a blind pigeon' according to him. "I just don't know why someone would do these three right, and do such a trashy job on this one."

Also, on the way back my windshield wipers wouldn't turn off. I opened the hood, and noticed the connector was not pushed in all the way. I pulled it open and water trickled out. I got my can of compressed air (I suggest keeping it onboard!) blew out the water, sprayed 'slot glide' (we use it in computer repair/upgrades - it's basically WD30), and it fixed the problem.

The coach is easy to maneuver in tight spots. It drives and moves much better than our Winnebago View did. I think I may have made a wrong turn, and had to do a quick turn around in a meth lab driveway. We were in a very scary part of WV at the time. Next time, I'm taking one of the Wild and Wonderful Whites of West Virginia with me for protection!

Quality issues aside, we really like the coach. Best layout and features for our style of travel. Like someone said before, "once you have the quality issues ironed out, you'll end up with a coach you really like". I just hope the quality issues get ironed out in at least 5 years or so.