Hello Everyone, I just completed a San Diego to Chicago round trip, as=
a maiden voyage after 2 years of renovations and upgrades. During the 4,50=
0+ mile trip, I was able to real world test everything. These are such grea=
t designs that it was a truly enjoyable adventure. I averaged an =E2=80=
=9Cincident=E2=80=9D about every other day. These were not breakdowns rathe=
r opportunities for improvement. I would like to share my observations and =
my opinions. I=E2=80=99m only relaying my experience, your trip experience =
will of course vary. The first day resulted in only a 150 mile progres=
s. Traveling slow and cautiously. This was the first time I had driven the =
GMC on the highway, actually the first time I had driven any RV on the high=
way. The size and width of the coach took getting used to. Accelerating an=
d braking performance was disappointing. Even though the entire brake syste=
m was completely new and the 455 was running perfectly. Weight and wind res=
istance can=E2=80=99t be avoided. San Diego county is mountainous with a ma=
x elevation of about 4800 feet. Climbing from 800 feet to 4800 feet was typ=
ically done at 40 mph full throttle. Ambient temp was 80*. The new fuel gau=
ges became random and served as =E2=80=9Cgeneral=E2=80=9D indicators. I lat=
er decided that 200 miles on the odometer and it was time to fill up. Fuel =
consumption for the trip averaged 11-12 mpg. The second day was brough=
t to a close with a broken belt that destroyed a second belt, leaving just =
1 belt running. It happened after a fuel stop. My new belts and fancy alter=
nator tensioner didn=E2=80=99t save me but the remaining single belt for th=
e PS, water pump and a/c did! Running on just the coach and house battery g=
ot me to the repair shop 50 miles down the road. $200 later I was ready to =
stop for the night. The third day was uneventful. Becoming comfortable=
with driving speeds at 65 mph. MPG didn=E2=80=99t change. The rebuilt dash=
a/c worked fine as we crossed the desert areas of California and Arizona. =
There were slight hard starts after fueling stops. With higher ambient temp=
s, venting of fuel became an issue. Trying to fill the tank(s) became messy=
. Almost every stop caused a few gallons of fuel to dump on the pavement. A=
lthough the entire fuel system including all hoses, clamps, sending units, =
replaced and tanks cleaned. Still don=E2=80=99t know why. The next day=
we noticed the smell of axle grease in the cab. Turns out the diff cover t=
hat was professionally resealed in San Diego was leaking badly. $100 later =
problem was fixed and remains good to this day. On the fifth day some =
where in the pan handle of Texas it was time to stop for the day. Driving t=
he entire day at 65 mph, ambient temp 99*, to say the least it was hot, hot=
, hot. A shower, a good meal and a good night=E2=80=99s sleep sounded perfe=
ct. However after positioning on the camp pad and shutting off the engine=
=E2=80=A6..BOOM and a fog of R134A. Pretty much got the attention of everyo=
ne in the camp ground. Carefully looking into the right wheel well exposed =
the separated end fitting from its hose at the a/c compressor. So much for =
the brand new after market a/c hose. The A/C was never repaired proper=
ly, although I spent several hundreds of dollars and a lot of time trying t=
o. Of all the on the road repairs I think A/C is the most difficult. I gave=
up when the last shop (after a day=E2=80=99s worth of effort} proclaimed 7=
0* at the dash outlet. The wife was beginning to dislike traveling in the G=
MC. After 3 months at our destination in the hot, humid Midwest it was=
time to bring the GMC home to Cali. Before leaving I thought I could=
improve the steering so I replaced the steering input shaft and CV joint. =
I discovered almost all the steering play was a result of wear in the splin=
ed slip shaft. Both were replaced anyway. The trip home incurred only two f=
ailures over 4 days of travel. The upgraded belt tensioner and belts that w=
ere replaced on the first half of the trip were installed wrong and caused =
the alternator belt to fail again. The shore power cable failed shorting gr=
ound to one phase. All in all an easy trip home. Now I was more relaxed wit=
h the motorhome and less tense and had several observations. When I first j=
oined this forum, it seemed that certain issues were a constant topic. Tire=
s=E2=80=A6.I used the steel rims with standard size 16.5 inch Firestone Tra=
nsforce HT tires set at 70 psi. 5000 miles with no wear/problem. Vapor Lock=
=E2=80=A6=E2=80=A6I run a new mechanical fuel pump with dual in line filter=
s and no inner fender liners. Occasional slow start but nothing to disable =
the engine. Overheating=E2=80=A6.Stock radiator, 180* thermostat, stock fan=
clutch, hi performance water pump (applied gmc). Temp guage max rise was 1=
needle width. Brakes=E2=80=A6.p30 master cylinder, 80mm calipers, fresh li=
nings, wheel cylinders. No brake fade. Always had a good pedal. I mention=
these because as a new owner and new to the forum I was worried that I did=
n=E2=80=99t take enough effort and money to be safe enough. All this migh=
t be the =E2=80=9Cminimum=E2=80=9D but with careful driving it seemed to me=
to be more than enough. I=E2=80=99m home but ready for the next GMC advent=
ure. The biggest surprise was when I noticed the GPS was reading 5 mph=
faster than the speedometer! Most of the driving was spent in the 65 =
=E2=80=93 70 mph range unknowingly! My next improvements are: sway bar=
s front and rear, new compressor for air ride, repair dash a/c, aux vac pum=
p Rod Utterback 1973 Canyonlands Escondido, Ca.
a maiden voyage after 2 years of renovations and upgrades. During the 4,50=
0+ mile trip, I was able to real world test everything. These are such grea=
t designs that it was a truly enjoyable adventure. I averaged an =E2=80=
=9Cincident=E2=80=9D about every other day. These were not breakdowns rathe=
r opportunities for improvement. I would like to share my observations and =
my opinions. I=E2=80=99m only relaying my experience, your trip experience =
will of course vary. The first day resulted in only a 150 mile progres=
s. Traveling slow and cautiously. This was the first time I had driven the =
GMC on the highway, actually the first time I had driven any RV on the high=
way. The size and width of the coach took getting used to. Accelerating an=
d braking performance was disappointing. Even though the entire brake syste=
m was completely new and the 455 was running perfectly. Weight and wind res=
istance can=E2=80=99t be avoided. San Diego county is mountainous with a ma=
x elevation of about 4800 feet. Climbing from 800 feet to 4800 feet was typ=
ically done at 40 mph full throttle. Ambient temp was 80*. The new fuel gau=
ges became random and served as =E2=80=9Cgeneral=E2=80=9D indicators. I lat=
er decided that 200 miles on the odometer and it was time to fill up. Fuel =
consumption for the trip averaged 11-12 mpg. The second day was brough=
t to a close with a broken belt that destroyed a second belt, leaving just =
1 belt running. It happened after a fuel stop. My new belts and fancy alter=
nator tensioner didn=E2=80=99t save me but the remaining single belt for th=
e PS, water pump and a/c did! Running on just the coach and house battery g=
ot me to the repair shop 50 miles down the road. $200 later I was ready to =
stop for the night. The third day was uneventful. Becoming comfortable=
with driving speeds at 65 mph. MPG didn=E2=80=99t change. The rebuilt dash=
a/c worked fine as we crossed the desert areas of California and Arizona. =
There were slight hard starts after fueling stops. With higher ambient temp=
s, venting of fuel became an issue. Trying to fill the tank(s) became messy=
. Almost every stop caused a few gallons of fuel to dump on the pavement. A=
lthough the entire fuel system including all hoses, clamps, sending units, =
replaced and tanks cleaned. Still don=E2=80=99t know why. The next day=
we noticed the smell of axle grease in the cab. Turns out the diff cover t=
hat was professionally resealed in San Diego was leaking badly. $100 later =
problem was fixed and remains good to this day. On the fifth day some =
where in the pan handle of Texas it was time to stop for the day. Driving t=
he entire day at 65 mph, ambient temp 99*, to say the least it was hot, hot=
, hot. A shower, a good meal and a good night=E2=80=99s sleep sounded perfe=
ct. However after positioning on the camp pad and shutting off the engine=
=E2=80=A6..BOOM and a fog of R134A. Pretty much got the attention of everyo=
ne in the camp ground. Carefully looking into the right wheel well exposed =
the separated end fitting from its hose at the a/c compressor. So much for =
the brand new after market a/c hose. The A/C was never repaired proper=
ly, although I spent several hundreds of dollars and a lot of time trying t=
o. Of all the on the road repairs I think A/C is the most difficult. I gave=
up when the last shop (after a day=E2=80=99s worth of effort} proclaimed 7=
0* at the dash outlet. The wife was beginning to dislike traveling in the G=
MC. After 3 months at our destination in the hot, humid Midwest it was=
time to bring the GMC home to Cali. Before leaving I thought I could=
improve the steering so I replaced the steering input shaft and CV joint. =
I discovered almost all the steering play was a result of wear in the splin=
ed slip shaft. Both were replaced anyway. The trip home incurred only two f=
ailures over 4 days of travel. The upgraded belt tensioner and belts that w=
ere replaced on the first half of the trip were installed wrong and caused =
the alternator belt to fail again. The shore power cable failed shorting gr=
ound to one phase. All in all an easy trip home. Now I was more relaxed wit=
h the motorhome and less tense and had several observations. When I first j=
oined this forum, it seemed that certain issues were a constant topic. Tire=
s=E2=80=A6.I used the steel rims with standard size 16.5 inch Firestone Tra=
nsforce HT tires set at 70 psi. 5000 miles with no wear/problem. Vapor Lock=
=E2=80=A6=E2=80=A6I run a new mechanical fuel pump with dual in line filter=
s and no inner fender liners. Occasional slow start but nothing to disable =
the engine. Overheating=E2=80=A6.Stock radiator, 180* thermostat, stock fan=
clutch, hi performance water pump (applied gmc). Temp guage max rise was 1=
needle width. Brakes=E2=80=A6.p30 master cylinder, 80mm calipers, fresh li=
nings, wheel cylinders. No brake fade. Always had a good pedal. I mention=
these because as a new owner and new to the forum I was worried that I did=
n=E2=80=99t take enough effort and money to be safe enough. All this migh=
t be the =E2=80=9Cminimum=E2=80=9D but with careful driving it seemed to me=
to be more than enough. I=E2=80=99m home but ready for the next GMC advent=
ure. The biggest surprise was when I noticed the GPS was reading 5 mph=
faster than the speedometer! Most of the driving was spent in the 65 =
=E2=80=93 70 mph range unknowingly! My next improvements are: sway bar=
s front and rear, new compressor for air ride, repair dash a/c, aux vac pum=
p Rod Utterback 1973 Canyonlands Escondido, Ca.
