Final Drive Ratio & Safe Water

[dave lowry]

Question: How can I tell the ratio of my final drive? My 26' '76 weighs
11,700# loaded and I seem to have adequate power on hills (except at high
altitude, of course), but would be curious to know if I have the original
3.07 gears. If so, switching to Caspro's 3.50 setup might make everything
(power, temperature & mileage) even better. Is there an easy way to tell if
my coach's final drive has been modified?

Suggestion: Keeping the fresh water system healthy is a constant problem.
Impurities are introduced every time the tank is filled. We do a thorough
sytem purification once a year, but in the interim are never sure what's in
the system. An easy way to insure safe water for cooking & drinking is to
use a portable purifier, like a Brita, Ecowater or Glacier Pure. They're
1/2 gallon carafe types and cost about $20. The filters aren't that much
since the filtered water is only used for drinking & cooking. ps: If the
regular pitcher doesn't hold enough, just keep some plastic bottles full of
filtered water in the frig.

Of course there's also the counter-top and under-the-counter types if
you're into plumbing and/or spending a little more $.

Regards and TIA, Dave

 

[bartz paul]

Two thoughts come to my mind, short of opening up the drive train (i. e.
differential, etc.) to see.

The best tip off would be what your engine RPM's are. They would be
higher than originally. However, if you don't have a tachometer, this
does not help you. For instance, with my 3.42:1 ring and pinion gear
and 403 cid engine, @ 65 mph my engine RPM is approximately 2600 whereas
previously it was around 2400 RPM.

Secondly, if other than having the original ring and pinion gear, you
need a device to correct the speedometer reading. It is one that is
installed directly on the speedometer cable pickup point on the
transmission ahead of the speedometer cable connector and is about half
the size of a pack of cigarettes. Of course, it's possible to have
other than original ring and pinion and it not have speedometer
correction.

Paul Bartz
- -----Original Message-----
From: dlowry [mailto:dlowry]
Sent: Wednesday, August 05, 1998 5:17 PM
To: gmcmotorhome
Subject: GMC: Final Drive Ratio & Safe Water

Question: How can I tell the ratio of my final drive? My 26' '76 weighs
11,700# loaded and I seem to have adequate power on hills (except at
high altitude, of course), but would be curious to know if I have the
original 3.07 gears. If so, switching to Caspro's 3.50 setup might make
everything (power, temperature & mileage) even better. Is there an easy
way to tell if my coach's final drive has been modified?
Suggestion: Keeping the fresh water system healthy is a constant
problem. Impurities are introduced every time the tank is filled. We do
a thorough system purification once a year, but in the interim are never
sure what's in the system. An easy way to insure safe water for cooking
& drinking is to use a portable purifier, like a Brita, Ecowater or
Glacier Pure. They're 1/2 gallon carafe types and cost about $20. The
filters aren't that much since the filtered water is only used for
drinking & cooking. ps: If the regular pitcher doesn't hold enough,
just keep some plastic bottles full of filtered water in the frig.
Of course there's also the counter-top and under-the-counter types if
you're into plumbing and/or spending a little more $.