Mountain Driving

Doesn’t changing the final drive from the stock 3.07 to 3.7 or 4.1 alleviate lot of these uphill/downhill problems. I intend to replace my 3.07 to 3.7 with lsd as driving through West Virginia and Pennsylvania mountains does not make my 77 Royale very happy. My goal this year is to drive the coach to the 2 continental states(Idaho and Montana) that I haven’t been to yet after the 3.7 final drive is installed.
 
I put a 3.70 Final Drive in my '75, 26' 455 equipped coach about 14 years ago. I still have to downshift to second gear and stand on the gas pedal quite frequently while climbing long and/or steep grades. it DOES get the engine up into the max torque level quicker and will help, but the lower gearing is not a miracle cure for climbing.
 
Carl Stouffer said:
I put a 3.70 Final Drive in my '75, 26' 455 equipped coach about 14 years ago. I still have to downshift to second gear and stand on the gas pedal quite frequently while climbing long and/or steep grades. it DOES get the engine up into the max torque level quicker and will help, but the lower gearing is not a miracle cure for climbing.
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Can you get up to a normal speed(50 mph+)? Or are you stuck with 35 mph speeds on the expressway?
 
wchrist1 said:
Can you get up to a normal speed(50 mph+)? Or are you stuck with 35 mph speeds on the expressway?
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I have a 3.70 final drive in my '73 with a 455 and while it loves its happy place at 60-65mph, I'm comfortable spinning it up to 75mph to get around someone. I just think its easier on everything if the engine spins a little faster. JWIT
 
dsmithy said:
I have a 3.70 final drive in my '73 with a 455 and while it loves its happy place at 60-65mph, I'm comfortable spinning it up to 75mph to get around someone. I just think its easier on everything if the engine spins a little faster. JWIT
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I guess I should have made it clear by saying, can I get to a normal speed(50+) while going uphill climbing up long and steep grades? Or am I stuck maxing out at 35 mph going uphill on steep grades on 4 lane highways? I don't intend mountain goating up 2 lane roads on mountains if I can help it.
 
wchrist1 said:
I guess I should have made it clear by saying, can I get to a normal speed(50+) while going uphill climbing up long and steep grades? Or am I stuck maxing out at 35 mph going uphill on steep grades on 4 lane highways? I don't intend mountain goating up 2 lane roads on mountains if I can help it.
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Depending on the grade, I can usually maintain between 40 and 50 mph. I am also towing a 2003, four door Tracker almost all the time. Total weight of over 15,000 lbs. I usually drive between 60 and 65 on flatter ground, and can maintain those speeds up minor grades, it's just when we tackle a 5 - 6% grade that we slow down a bit
 
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The interstate, red, white and blue signs, adhere to national standards and grades both up and down are generally fine in the GMC. In fact, most times you will have to add a little accelerator when you're driving downhill.

The Appalachian state roads, black and white signs, many of which date way back before the road system out west, can be found to be steep and dangerous. Be careful as your GPS does not differentiate. Brake over heating and break fluid boiling is cumulative. It often happens over time and not one single event. Make sure you stop periodically to cool the system down. Absolutely down shift when necessary.

Simply be careful and do not rush it when going through the mountains. I have had brake failures in concrete trucks, dump trucks and an event in the GMC. Heat is your enemy.
 
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What routes across the mountains have the least grades? When going to the Waynesville rally, I found the 6% grade on I-40 at Black Mountain to be almost too much. Are there better routes up in Virginia/West Virginia to get over towards Paducah?
 
radcaddy said:
What routes across the mountains have the least grades? When going to the Waynesville rally, I found the 6% grade on I-40 at Black Mountain to be almost too much. Are there better routes up in Virginia/West Virginia to get over towards Paducah?
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I use rvlife.com Trip Wizard which shows elevation and gradient of your planned route. It’s a great app that also includes turn-by-turn navigation and RV-safe routing (avoiding low clearance bridges, tunnel restrictions, etc).

www.rvlife.com
 
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Christo said:
I use rvlife.com trip planner which shows elevation and gradient of your planned route. It’s a great app that also includes turn-by-turn navigation and RV-safe routing (avoiding low clearance bridges, tunnel restrictions, etc).
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Does it have a setting to automatically steer you to every Cracker Barrel enroute? You guys travel just like we travel!
 
Tom Katzenberger said:
The interstate, red, white and blue signs, adhere to national standards and grades both up and down are generally fine in the GMC. In fact, most times you will have to add a little accelerator when you're driving downhill.

The Appalachian state roads, black and white signs, many of which date way back before the road system out west, can be found to be steep and dangerous. Be careful as your GPS does not differentiate. Brake over heating and break fluid boiling is cumulative. It often happens over time and not one single event. Make sure you stop periodically to cool the system down. Absolutely down shift when necessary.

Simply be careful and do not rush it when going through the mountains. I have had brake failures in concrete trucks, dump trucks and an event in the GMC. Heat is your enemy.
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Double emphasis on overheat causing boiling. I've had it happen twice. Once going down a hill I should have never gone up. Completely lost pedal pressure, although could pump up. Fortunately, I was on a wide, empty stretch of road. By the time I got to town pressure was back.
Second time had partial pressure loss because I forgot to release the ebrake.

Quick note here regarding proportioning valve. That's the cute device that shuttles to block the fluid flow to the line with no pressure. Resetting it is done by stomping on the brake pedal with the engine off once the fluid loss has been corrected. If it was a leak, you'll likely have to pump the pedal until you get some kind of pressure and then stompity stomp stomp to move that shuttle. If no luck there it's probably gunked up and stuck and you'll have to replace.
 
I also think the front of the coach provides a significant amount of wind resistance at speed helping to keep her slowed down when going downhill.
 
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