Home » Public Forums » GMCnet » 66 Toronado 3.21 planetary differential final drive question
| 66 Toronado 3.21 planetary differential final drive question [message #240941] |
Sun, 23 February 2014 07:30  |
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Bill Freeman
Messages: 122
Registered: March 2004
Location: Colerain, NC
Karma: 1
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Rob,
You said
I run a 3.21 to 1 (66 Toronado Planetary Gear FD) in Double Trouble. I don't know what the rpm's are at 60 but I do know that at 70
the engine is turning around 2400 rpm. The engine absolutely LOVES that rpm and will do it all day long.
I would like to know what, if any, modifications to other drive line components are required to use the 66 final drive in a GMC? I ask because I have a fair number of these planetary final drives in my collection of Toronados. I know the inboard universal joint is unique to a 66 but hoping the stub axle splines of the GMC will fit the 66 FD.
Bill Freeman
78 Royale 73 Sequoia
Colerain, North Carolina
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| Re: [GMCnet] 66 Toronado 3.21 planetary differential final drive question [message #240943 is a reply to message #240941] |
Sun, 23 February 2014 08:03  |
scott cowden
Messages: 170
Registered: February 2004
Karma: 0
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Good morning, Bill;
I have an entire '66 trans and final drive in my coach. The trans was rebuilt and 'hardened,' for motor home use. It works well and having access to the switch pitch is handy on hills and such. I have mine controlled by a switch on the dash so I can toggle back and forth at will.
As for the final drive, you will need the right side intermediary shaft from the 3:21 as the splines are different than the later model drives. If you've got that part, and it sounds like you've got several potential donors, its a relatively easy bolt-in job.
If you look at http://appliedgmc.com/level.itml/icOid/482 There is a table on comparative rpm at speed with the various FD ratio's. unfortunately, he hasn't listed the 3:21, but you can take a stab at where this drive falls between the 3:07 and 3:42.
It's tough to say definitvely, but the planetary system appears to work well in low traction situations. I've gotten into and out of situations where I really questioned the coach's abilities previously on wet grass and soft ground.
HTH
Scott Cowden
'74 x-Glacier
Newmarket ON
Canada
@temp.gmcnet.org
> From: flipflapco@gmail.com
> Date: Sun, 23 Feb 2014 07:30:11 -0600
> Subject: [GMCnet] 66 Toronado 3.21 planetary differential final drive question
>
>
>
> Rob,
> You said
> I run a 3.21 to 1 (66 Toronado Planetary Gear FD) in Double Trouble. I don't know what the rpm's are at 60 but I do know that at 70
> the engine is turning around 2400 rpm. The engine absolutely LOVES that rpm and will do it all day long.
>
> I would like to know what, if any, modifications to other drive line components are required to use the 66 final drive in a GMC? I ask because I have a fair number of these planetary final drives in my collection of Toronados. I know the inboard universal joint is unique to a 66 but hoping the stub axle splines of the GMC will fit the 66 FD.
> --
> Bill Freeman
> 78 Royale 73 Sequoia
> Colerain, North Carolina
> http://tinyurl.com/yx7nra
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
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| Re: [GMCnet] 66 Toronado 3.21 planetary differential final drive question [message #240952 is a reply to message #240947] |
Sun, 23 February 2014 08:35 |
scott cowden
Messages: 170
Registered: February 2004
Karma: 0
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Senior Member |
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Bill;
I suspect that if you offered up the trans/final drives to the community, they'd be sold in relative short order. I bought mine nearly 10 years ago and it sat in my garage about 5 years before I finally got around to having it set up and installed, but as they're not making any more of them, like-minded guys will grab them now and do them when time and resources permit. Hell, I'm tempted to buy another one, just 'cause you never know.......
Scott
'74 x-Glacier
Newmarket ON
Canada
> To: gmclist@temp.gmcnet.org
> From: flipflapco@gmail.com
> Date: Sun, 23 Feb 2014 08:22:06 -0600
> Subject: Re: [GMCnet] 66 Toronado 3.21 planetary differential final drive question
>
>
>
> Scott,
>
> Thanks, that sounds easy enough. I have a half dozen 66 Toronados. Maybe I should also investigate the suggested mods to the switch pitch transmissions. I may as well part them out now since the vandals had their way with all the windows three years ago.
>
> As for the final drive, you will need the right side intermediary shaft from the 3:21 as the splines are different than the later model drives.
>
>
> --
> Bill Freeman
> 78 Royale 73 Sequoia
> Colerain, North Carolina
> http://tinyurl.com/yx7nra
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
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| Re: [GMCnet] 66 Toronado 3.21 planetary differential final drive question [message #240994 is a reply to message #240943] |
Sun, 23 February 2014 12:54 |
Kosier
Messages: 834
Registered: February 2008
Karma: 1
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Senior Member |
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--
--,
Check Ken Henderson's stuff on the Photosite for a good chart on gear ratios
and final drive RPMs.
Gary Kosier
77 PB w/Cad 500
Newark, Oh
-----Original Message-----
From: scott cowden
Sent: Sunday, February 23, 2014 9:03 AM
To: gmclist@temp.gmcnet.org
Subject: Re: [GMCnet] 66 Toronado 3.21 planetary differential final drive
question
Good morning, Bill;
I have an entire '66 trans and final drive in my coach. The trans was
rebuilt and 'hardened,' for motor home use. It works well and having access
to the switch pitch is handy on hills and such. I have mine controlled by a
switch on the dash so I can toggle back and forth at will.
As for the final drive, you will need the right side intermediary shaft from
the 3:21 as the splines are different than the later model drives. If
you've got that part, and it sounds like you've got several potential
donors, its a relatively easy bolt-in job.
If you look at http://appliedgmc.com/level.itml/icOid/482 There is a table
on comparative rpm at speed with the various FD ratio's. unfortunately, he
hasn't listed the 3:21, but you can take a stab at where this drive falls
between the 3:07 and 3:42.
It's tough to say definitvely, but the planetary system appears to work well
in low traction situations. I've gotten into and out of situations where I
really questioned the coach's abilities previously on wet grass and soft
ground.
HTH
Scott Cowden
'74 x-Glacier
Newmarket ON
Canada
@temp.gmcnet.org
> From: flipflapco@gmail.com
> Date: Sun, 23 Feb 2014 07:30:11 -0600
> Subject: [GMCnet] 66 Toronado 3.21 planetary differential final drive
> question
>
>
>
> Rob,
> You said
> I run a 3.21 to 1 (66 Toronado Planetary Gear FD) in Double Trouble. I
> don't know what the rpm's are at 60 but I do know that at 70
> the engine is turning around 2400 rpm. The engine absolutely LOVES that
> rpm and will do it all day long.
>
> I would like to know what, if any, modifications to other drive line
> components are required to use the 66 final drive in a GMC? I ask because
> I have a fair number of these planetary final drives in my collection of
> Toronados. I know the inboard universal joint is unique to a 66 but
> hoping the stub axle splines of the GMC will fit the 66 FD.
> --
> Bill Freeman
> 78 Royale 73 Sequoia
> Colerain, North Carolina
> http://tinyurl.com/yx7nra
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
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| Re: 66 Toronado 3.21 planetary differential final drive question [message #241002 is a reply to message #240941] |
Sun, 23 February 2014 14:07 |
cbryan
Messages: 451
Registered: May 2012
Location: Ennis, Texas
Karma: 3
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Senior Member |
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Bill,
Interpolating from the Applied GMC chart, it looks like a 3.21 final drive ratio in the GMC Motorhome should run about 2390 rpm at 60 mph. Rob Mueller says he got 2400 at 70 mph running the 3.21. Tires get bigger south of the equator, Rob? There's the torque converter slip to be factored in, and speedometer error, too. Time for someone else with experience to chime in. With improvements in engine builds, cams, EFI, I am thinking 3.21 is a pretty good ratio. True, you seldom get up to the torque peak in third gear, but like the fellow running the 2.73, he enjoyed better gas mileage, and ran a lot of second gear and had no problem getting up hills. He used the 2.73 as an overdrive, and used second gear more often, and first gear and torque multiplication seemed to take care of the takeoff. I don't think this was a good towing setup, though.
There is the effect we all see when we adjust to a vehicle. We are glad when it is running "properly" and won't complain if it keeps running and doesn't leave us at the side of the road, and is powerful enough to get you where you are going. I had a family friend in boyhood whose dad was notoriously tight with the nickels. He drove five kids and he and mom in a 1959 Chevrolet station wagon, roof rack packed. 6 cylinder and the two speed cast iron Powerglide automatic. They went down into Bryce Canyon out west. It would have been faster to walk out at times. The sons were scandalized and disgusted at the lack of speed. They got home, slowly. The 40 hp Volkswagen engine in a VW van was not any world beater in acceleration. It had a 0 - 60 time of infinity. It topped out at 59! I imagine any GMC would accelerate faster than that puppy. I drove and rode in one of those VWs from Colorado to North Carolina. I drafted truckers quite a bit. Otherwise it was third gear city. (Of four forward gears.) You knew all about hills and headwinds.
Carey
Carey from Ennis, Texas
78 Royale, 500 Cadillac, Rance Baxter EFI.
[Updated on: Sun, 23 February 2014 14:09] Report message to a moderator |
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| Re: [GMCnet] 66 Toronado 3.21 planetary differential final drivequestion [message #241027 is a reply to message #241002] |
Sun, 23 February 2014 17:12 |
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USAussie
Messages: 15912
Registered: July 2007
Location: Sydney, Australia
Karma: 6
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Senior Member |
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Carey,
Hmmmmm, I looked at the chart and you are correct, there's no way that Double Trouble was running 70 mph at 2400 rpm! It's bloody
impossible.
Guess my CRS kicked in on this one, SORRY!
Regards,
Rob M.
Sydney, Australia
AUS '75 Avion - The Blue Streak TZE365V100428
USA '75 Avion - Double Trouble TZE365V100426
-----Original Message-----
From: Carey Bryan
Bill,
Interpolating from the Applied GMC chart, it looks like a 3.21 final drive ratio in the GMC Motorhome should run about 2390 rpm at
60 mph. Rob Mueller says he got 2400 at 70 mph running the 3.21. Tires get bigger south of the equator, Rob? There's the torque
converter slip to be factored in, and speedometer error, too. Time for someone else with experience to chime in. With improvements
in engine builds, cams, EFI, I am thinking 3.21 is a pretty good ratio. True, you seldom get up to the torque peak in third gear,
but like the fellow running the 2.73, he enjoyed better gas mileage, and ran a lot of second gear and had no problem getting up
hills. He used the 2.73 as an overdrive, and used second gear more often, and first gear and torque multiplication seemed to take
care of the takeoff. I don't think this was a good towing setup, though.
There is the effect we all see when we adjust to a vehicle. We are glad when it is running "properly" and won't complain if it
keeps running and doesn't leave us at the side of the road, and is powerful enough to get you where you are going. I had a family
friend in boyhood whose dad was notoriously tight with the nickels. He drove five kids and he and mom in a 1959 Chevrolet station
wagon, roof rack packed. 6 cylinder and the two speed cast iron Powerglide automatic. They went down into Bryce Canyon out west.
It would have been faster to walk out at times. The sons were scandalized and disgusted at the lack of speed. The 40 hp Volkswagen
engine in a VW van was not any world beater in acceleration. It had a 0 - 60 time of infinity. It topped out at 59! I imagine any
GMC would accelerate faster than that puppy. I drove and rode in one of those VWs from Colorado to North Carolina. I drafted
truckers quite a bit. Otherwise it was third gear city. (Of four forward gears.) You knew all about hills and headwinds.
Carey
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Regards,
Rob M. (USAussie)
The Pedantic Mechanic
Sydney, Australia
'75 Avion - AUS - The Blue Streak TZE365V100428
'75 Avion - USA - Double Trouble TZE365V100426
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| Re: [GMCnet] 66 Toronado 3.21 planetary differential final drive question [message #241055 is a reply to message #240943] |
Sun, 23 February 2014 20:30 |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
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Senior Member |
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Here's a ratio table that does include the 3.21. It doesn't give engine
speeds, but if you've got that for one combination, it's trivial to
calculate for any other.
http://www.gmcmhphotos.com/photos/odds-n-ends/p41230-overall-gear-ratios.html
Ken H.
On Sun, Feb 23, 2014 at 9:03 AM, scott cowden wrote:
>
> Good morning, Bill;
> ...
>
> If you look at http://appliedgmc.com/level.itml/icOid/482 There is a
> table on comparative rpm at speed with the various FD ratio's.
> unfortunately, he hasn't listed the 3:21, but you can take a stab at
> where this drive falls between the 3:07 and 3:42.
> ...
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Ken Henderson
Americus, GA
www.gmcwipersetc.com
Large Wiring Diagrams
76 X-Birchaven
76 X-Palm Beach
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| Re: [GMCnet] 66 Toronado 3.21 planetary differential final drive question [message #241073 is a reply to message #240947] |
Sun, 23 February 2014 22:07 |
John Biwersi
Messages: 78
Registered: July 2006
Location: Maplewood,
Karma: 1
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Bill, The round inner CV joint that you have in your 66 Toros was also used in some 67 Toros. These CVs are what I would call a ball bearing style which I think is a better design than the triangle needle bearing style which was used from mid model 67 to 78 Toros, 67 to 78 Cadillac Eldorados and 73-78 GMC Motorhomes. I suspect the reason for the change was cost. To use these ball bearing style on your motorhome you need to have the mating 3.21 intermediate axle because the od of the flange of these CV's is approximately 1/8" larger than the triangular style. Since you have 66 Toros, you have the correct intermediate shafts. If you decide to use the 66 Toro inner CV's, I can supply you boot kits if you have need. If you decide to part out your collection of Toros, I suspect Manny would be interested in the torque convertors, transmissions, final drives, and the right hand intermediate shafts. Also if you decide to install a 3.21 in your coach, give me a call and we can discuss your options as to the right hand seal, and suggested modifications to the final drive cover.
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| Re: [GMCnet] 66 Toronado 3.21 planetary differential final drivequestion [message #241086 is a reply to message #241073] |
Mon, 24 February 2014 00:09 |
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USAussie
Messages: 15912
Registered: July 2007
Location: Sydney, Australia
Karma: 6
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Senior Member |
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John,
In a 3.21 to 1 final drive how many teeth are there on the:
A) Pinion:
B) Ring Gear:
Please advise.
Regards,
Rob M.
Sydney, Australia
AUS '75 Avion - The Blue Streak TZE365V100428
USA '75 Avion - Double Trouble TZE365V100426
-----Original Message-----
From: John Biwersi
Bill, The round inner CV joint that you have in your 66 Toros was also used in some 67 Toros. These CVs are what I would call a ball
bearing style which I think is a better design than the triangle needle bearing style which was used from mid model 67 to 78 Toros,
67 to 78 Cadillac Eldorados and 73-78 GMC Motorhomes. I suspect the reason for the change was cost. To use these ball bearing style
on your motorhome you need to have the mating 3.21 intermediate axle because the od of the flange of these CV's is approximately
1/8" larger than the triangular style. Since you have 66 Toros, you have the correct intermediate shafts. If you decide to use the
66 Toro inner CV's, I can supply you boot kits if you have need. If you decide to part out your collection of Toros, I suspect
Manny would be interested in the torque convertors, transmissions, final drives, and the right hand intermediate shafts. Also if you
decide to install a 3.21 in your coach, give me a call and we can discuss your options as to the right hand seal, and suggested
modifications to the final drive cover.
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Regards,
Rob M. (USAussie)
The Pedantic Mechanic
Sydney, Australia
'75 Avion - AUS - The Blue Streak TZE365V100428
'75 Avion - USA - Double Trouble TZE365V100426
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| Re: [GMCnet] 66 Toronado 3.21 planetary differential final drive question [message #241118 is a reply to message #240952] |
Mon, 24 February 2014 10:02 |
GMC_LES
Messages: 569
Registered: October 2009
Location: Montreal
Karma: 0
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Senior Member |
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Scott, and anyone willing to pick-up,
I have 4 switch pitch transmissions here in montreal, 3 have the 3.21 FD. i will probably sell at least 2 of them this coming summer. I'm willing to negotiate and storage isn't an issue. Make an offer if interested.
Les Burt
Montreal
1975 Eleganza 26ft
A work in Progress
On Feb 23, 2014, at 9:35 AM, scott cowden <scottyforsail@hotmail.com> wrote:
Bill;
I suspect that if you offered up the trans/final drives to the community, they'd be sold in relative short order. I bought mine nearly 10 years ago and it sat in my garage about 5 years before I finally got around to having it set up and installed, but as they're not making any more of them, like-minded guys will grab them now and do them when time and resources permit. Hell, I'm tempted to buy another one, just 'cause you never know.......
Scott
'74 x-Glacier
Newmarket ON
Canada
> To: gmclist@temp.gmcnet.org
> From: flipflapco@gmail.com
> Date: Sun, 23 Feb 2014 08:22:06 -0600
> Subject: Re: [GMCnet] 66 Toronado 3.21 planetary differential final drive question
>
>
>
> Scott,
>
> Thanks, that sounds easy enough. I have a half dozen 66 Toronados. Maybe I should also investigate the suggested mods to the switch pitch transmissions. I may as well part them out now since the vandals had their way with all the windows three years ago.
>
> As for the final drive, you will need the right side intermediary shaft from the 3:21 as the splines are different than the later model drives.
>
>
> --
> Bill Freeman
> 78 Royale 73 Sequoia
> Colerain, North Carolina
> http://tinyurl.com/yx7nra
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
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Les Burt
Montreal
1975 Eleganza 26ft
A work in Progress
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