FYI, here is some recent interesting dialogue on the Toro mailinglist about
transmission, in particular Caspro's Power Drive unit, and final drive
options.
Bruce Roe's input talks about Caspro's 6-speed transmission/switch pitch
trans and a controller he builds.
Paul Bartz
Date: Tue, 1 Jun 1999 09:40:27 -0400
From: "Bartz, Paul"
Subject: [Toro] RE: Toro Digest V1 #1003
Alex:
As a GMC Motorhome owner, I can fill you in on the various final drive
ratios currently available. The Motorhome was only produced from 1973 -
1978, in just under 13,000 units, and only with the 3.07:1 ring and pinion
gears.
The "Castor" mentioned below is "Caspro". Their Power Drive unit
effectively gives the equivalent of a 3.50:1 final drive ratio. Some
Motorhome owners have installed the Toro 3.21:1 ring and pinion gears
individually and in conjunction with the Power Drive, which then gives an
effective ratio of 3.66:1.
There are several other final drive ring and pinion gear sets available now
also. Cinnabar has a 3.42:1, which I have installed. Two others are a
3.55:1 and a 3.67:1.
Except for the 3.21:1 ratio, each of the above mentioned units cost
approximately $800, exclusive of installation.
If you need sources for any of the above, I can furnish upon request.
Date: Mon, 31 May 1999 08:06:18 -0700
From: "don smith"
Subject: Re: [Toro] Pike's Peak chain sproket set for '66 Toro
Castor makes new chain drives for toro drivetrains (in GMC motorhome guise),
I believe they are 3.5 to 1 (the powerdrive unit I think they are advertised
at. Seems I remember in the cataloge a 6 speed TH 425 as well for mega$$$!
From: AlexDownie
Subject: Re: [Toro] Pike's Peak chain sproket set for '66 Toro
Date: Monday, May 31, 1999 12:06 AM
Anyone know anything about GM producing a special set of sprokets for the
chain drive with more teeth on one of the sprockets to alter the final drive
ratio? This was supposedly done to raise the effective drive ratio for
hill-climbing contests that showcased the then new Toronado's traction
prowess (late 1965).
What would the effective ratio have been? Where can I find out more about
this? Were the sprokets ever made available as a GM part No.?
Along the same lines, I know GM produced motorhomes based on the Toro FWD
platform. Did these use the stock final drive ratio (3.21/3.07 in '68 up)?
Or did they use a higher numerical ratio? How was this achieved? A new
ring & pinion or altered chain drive sprokets?
Date: Tue, 1 Jun 1999 10:14:39 -0500 (CDT)
From: bcroe (Bruce C Roe)
Subject: [Toro] Chain
Alex, I would like to add to Pauls' info. The Caspro "Power Drive" chain
assembly uses a stock 65 tooth sprocket with a 57 tooth to achieve a 1.140:1
ratio which in effect multiplies the final drive ratio. It includes a
(otherwise unavailable) new chain, bearings, and seals, making a TH425 trans
rebuild a lot simpler. The exciting news is the unit can be ordered with
the sprockets REVERSED (I have one) to DIVIDE the final drive ratio and save
a lot of gas.
I believe Ralph Braun will be publishing an article I wrote in the Toro
newsletter giving all the possible ratios and more info.
The Caspro 6 speed TH425 is based on a switch pitch trans combined with a
special motor home version of my electronic switch pitch controller. The
trans has a long list of improvements over a stock 67 trans: better gears,
shift kit, Power Drive, reinforced torque converter, center bearing support
with case protection ring, to mention a few. Its probably overkill for a
car.
Speaking of 6 speed switch pitch, I ordered the crucial parts last week for
another batch of switch pitch electronic controllers (car version). Anyone
who is interested could let me know, and I'll mail you the details this
month/ units in July.
transmission, in particular Caspro's Power Drive unit, and final drive
options.
Bruce Roe's input talks about Caspro's 6-speed transmission/switch pitch
trans and a controller he builds.
Paul Bartz
Date: Tue, 1 Jun 1999 09:40:27 -0400
From: "Bartz, Paul"
Subject: [Toro] RE: Toro Digest V1 #1003
Alex:
As a GMC Motorhome owner, I can fill you in on the various final drive
ratios currently available. The Motorhome was only produced from 1973 -
1978, in just under 13,000 units, and only with the 3.07:1 ring and pinion
gears.
The "Castor" mentioned below is "Caspro". Their Power Drive unit
effectively gives the equivalent of a 3.50:1 final drive ratio. Some
Motorhome owners have installed the Toro 3.21:1 ring and pinion gears
individually and in conjunction with the Power Drive, which then gives an
effective ratio of 3.66:1.
There are several other final drive ring and pinion gear sets available now
also. Cinnabar has a 3.42:1, which I have installed. Two others are a
3.55:1 and a 3.67:1.
Except for the 3.21:1 ratio, each of the above mentioned units cost
approximately $800, exclusive of installation.
If you need sources for any of the above, I can furnish upon request.
Date: Mon, 31 May 1999 08:06:18 -0700
From: "don smith"
Subject: Re: [Toro] Pike's Peak chain sproket set for '66 Toro
Castor makes new chain drives for toro drivetrains (in GMC motorhome guise),
I believe they are 3.5 to 1 (the powerdrive unit I think they are advertised
at. Seems I remember in the cataloge a 6 speed TH 425 as well for mega$$$!
From: AlexDownie
Subject: Re: [Toro] Pike's Peak chain sproket set for '66 Toro
Date: Monday, May 31, 1999 12:06 AM
Anyone know anything about GM producing a special set of sprokets for the
chain drive with more teeth on one of the sprockets to alter the final drive
ratio? This was supposedly done to raise the effective drive ratio for
hill-climbing contests that showcased the then new Toronado's traction
prowess (late 1965).
What would the effective ratio have been? Where can I find out more about
this? Were the sprokets ever made available as a GM part No.?
Along the same lines, I know GM produced motorhomes based on the Toro FWD
platform. Did these use the stock final drive ratio (3.21/3.07 in '68 up)?
Or did they use a higher numerical ratio? How was this achieved? A new
ring & pinion or altered chain drive sprokets?
Date: Tue, 1 Jun 1999 10:14:39 -0500 (CDT)
From: bcroe (Bruce C Roe)
Subject: [Toro] Chain
Alex, I would like to add to Pauls' info. The Caspro "Power Drive" chain
assembly uses a stock 65 tooth sprocket with a 57 tooth to achieve a 1.140:1
ratio which in effect multiplies the final drive ratio. It includes a
(otherwise unavailable) new chain, bearings, and seals, making a TH425 trans
rebuild a lot simpler. The exciting news is the unit can be ordered with
the sprockets REVERSED (I have one) to DIVIDE the final drive ratio and save
a lot of gas.
I believe Ralph Braun will be publishing an article I wrote in the Toro
newsletter giving all the possible ratios and more info.
The Caspro 6 speed TH425 is based on a switch pitch trans combined with a
special motor home version of my electronic switch pitch controller. The
trans has a long list of improvements over a stock 67 trans: better gears,
shift kit, Power Drive, reinforced torque converter, center bearing support
with case protection ring, to mention a few. Its probably overkill for a
car.
Speaking of 6 speed switch pitch, I ordered the crucial parts last week for
another batch of switch pitch electronic controllers (car version). Anyone
who is interested could let me know, and I'll mail you the details this
month/ units in July.
