Home » Public Forums » GMCnet » 3.42 ratio rear end sources?
| 3.42 ratio rear end sources? [message #102396] |
Sun, 10 October 2010 10:32  |
Rick
Messages: 36
Registered: September 2010
Location: Ft. Worth
Karma: 0
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What cars did the 3.42 ratio rear end come in? Searching hasn't helped me.
Planning a trip the the "Mens Mall" soon and thought I'd look for one of these as well.
Suggestions regarding the 3.42?
Are there pitfalls I am overlooking? I am aware of the speedo adaption issue.
What parts should I get with the unit?
Any tips would be appreciated
Thanks
Rick
Rick Does Ft. Worth Tx
1976 Glenbrook "Some Assembly Required"
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| Re: [GMCnet] 3.42 ratio rear end sources? [message #102400 is a reply to message #102396] |
Sun, 10 October 2010 10:43  |
jimk
Messages: 6734
Registered: July 2006
Location: Belmont, CA
Karma: 9
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Rick,
The 3,42 ratio was on the drawings at GM along with the 3.54.
These were only only for the front wheel drive,
These are a common ratio for all GM.
If you think you can adopt one to fit the front,you'll be in for lot
of frustration.
I can supply you just the gears for $450.
On Sun, Oct 10, 2010 at 8:32 AM, Rick Does <technicalninja@yahoo.com> wrote:
>
>
> What cars did the 3.42 ratio rear end come in? Searching hasn't helped me.
> Planning a trip the the "Mens Mall" soon and thought I'd look for one of these as well.
> Suggestions regarding the 3.42?
> Are there pitfalls I am overlooking? I am aware of the speedo adaption issue.
> What parts should I get with the unit?
> Any tips would be appreciated
> Thanks
> Rick
>
> --
> Rick Does                     Ft. Worth Tx
> 1976 Glenbrook "Some Assembly Required"
>
>
>
> _______________________________________________
> GMCnet mailing list
> List Information and Subscription Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>
--
Jim Kanomata
Applied/GMC, Fremont,CA
jimk@appliedairfilters.com
http://www.appliedgmc.com
1-800-752-7502
_______________________________________________
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Jim Kanomata
Applied/GMC
jimk@appliedairfilters.com
www.appliedgmc.com
1-800-752-7502
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| Re: [GMCnet] 3.42 ratio rear end sources? [message #102402 is a reply to message #102396] |
Sun, 10 October 2010 10:45 |
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USAussie
Messages: 15912
Registered: July 2007
Location: Sydney, Australia
Karma: 6
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Rick,
IIRC the final drives in Toronados and Eldorados came in three ratios:
2.73 to 1
3.07 to 1
3.21 to 1 (planetary gears) 1966 & 1967
IIRC the 3.42 to 1 is sold by Cinnabar.
Jim K. sells 3.55, 3.70, and 4.10 ratios:
http://www.appliedgmc.com/prod.itml/icOid/606
Regards,
Rob
-----Original Message-----
From: gmclist-bounces@temp.gmcnet.org
[mailto:gmclist-bounces@temp.gmcnet.org] On Behalf Of Rick Does
Sent: Sunday, October 10, 2010 10:32 AM
To: gmclist@temp.gmcnet.org
Subject: [GMCnet] 3.42 ratio rear end sources?
What cars did the 3.42 ratio rear end come in? Searching hasn't helped me.
Planning a trip the the "Mens Mall" soon and thought I'd look for one of
these as well.
Suggestions regarding the 3.42?
Are there pitfalls I am overlooking? I am aware of the speedo adaption
issue.
What parts should I get with the unit?
Any tips would be appreciated
Thanks
Rick
--
Rick Does Ft. Worth Tx
1976 Glenbrook "Some Assembly Required"
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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: 3.42 ratio rear end sources? [message #102424 is a reply to message #102396] |
Sun, 10 October 2010 16:06 |
Rick
Messages: 36
Registered: September 2010
Location: Ft. Worth
Karma: 0
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Thanks for the replies,
This explains why I had such bad luck searching.
Found lots of info comparing the 3.55 to the 3.42 and in-advertantly thought the 3.42 was a "common ratio" IE installed from the factory in something else that used the TH425/325 transmission. My understanding now is the lowest ratio installed by GM is the 3.07 for the later 10 bolt housings. (disregarding the early Toro stuff).
I wouldn't try to re-engineer an application like this; dissapointment and possibly destruction live down that road.
Much easier to purchase already re-engineered stuff if available.
If I were going the rebuild the diff route I'd probably opt for Jim K's 3.55 ratio.
Was hoping for an inexpensive route for a lower gear ratio.
Thanks again
Rick
Rick Does Ft. Worth Tx
1976 Glenbrook "Some Assembly Required"
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| Re: 3.42 ratio rear end sources? [message #102442 is a reply to message #102396] |
Sun, 10 October 2010 18:44 |
Rick
Messages: 36
Registered: September 2010
Location: Ft. Worth
Karma: 0
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Hello Rob, You met my Dad down in S.A this weekend. He had a great time swapping stories with you.
How did you end up with VINs so close together and the coaches so far apart? Are you looking for 100427?
One of the problems I will face is the need for a limited slip option down the road. The final drivetrain package I envision will require one. I have not seen references to a LSD option or availability regarding the 3.21 set. I haven't looked real hard yet either.
As I also envision it being switch pitch I need the early Toro/Eldo tanny anyway and am avidly searching for a good core to build. $200 would be a purchase point for me as well. I will end up owning the 3.21 regardless if I use it or not.
I was looking for a cheap quick gear upgrade that I could add to the stock coach before the final transaxle gets built.
Not to be.
Rick Does Ft. Worth Tx
1976 Glenbrook "Some Assembly Required"
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| Re: 3.42 ratio rear end sources? [message #102445 is a reply to message #102442] |
Sun, 10 October 2010 19:44 |
Neil
Messages: 271
Registered: July 2007
Location: Los Angeles and Magalia, ...
Karma: 1
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"I have not seen references to a LSD option or availability regarding the 3.21 set. I haven't looked real hard yet either."
Rick,
look no further than Jim K at applied gmc for an LSD in a variety of ratios. I have one - - it works!
Neil
76 Eleganza now sold
Los Angeles
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| Re: 3.42 ratio rear end sources? [message #102450 is a reply to message #102424] |
Sun, 10 October 2010 20:14 |
shawnee
Messages: 422
Registered: February 2004
Location: NC
Karma: 0
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| Rick wrote on Sun, 10 October 2010 17:06 |
Thanks for the replies,
This explains why I had such bad luck searching.
Found lots of info comparing the 3.55 to the 3.42 and in-advertantly thought the 3.42 was a "common ratio" IE installed from the factory in something else that used the TH425/325 transmission. My understanding now is the lowest ratio installed by GM is the 3.07 for the later 10 bolt housings. (disregarding the early Toro stuff).
I wouldn't try to re-engineer an application like this; dissapointment and possibly destruction live down that road.
Much easier to purchase already re-engineered stuff if available.
If I were going the rebuild the diff route I'd probably opt for Jim K's 3.55 ratio.
Was hoping for an inexpensive route for a lower gear ratio.
Thanks again
Rick
|
Rick,
As I understand it Toronados with towing option had 3.07 final drives and 2.73 ratio without the towing option. I know I installed a 2.73 ratio in my motorhome from a Toronado we scrapped and thought it was a 3.07. Driving on the Interstate I found I was running around 89mph when my speedometer registered between 65 and 70. The 3.21 ratio was in earlier Toronados and I am planning to install one this winter..
Gene Dotson
74 Canyonlands
www.bdub.net/Motorhome_Enhancements New Windows and Aluminum Radiators
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| Re: [GMCnet] 3.42 ratio rear end sources? [message #102468 is a reply to message #102464] |
Sun, 10 October 2010 21:17 |
Ray Erspamer
Messages: 1707
Registered: May 2007
Location: Milwaukee Wisconsin
Karma: -3
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Senior Member |
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My PO's records says that he put in a 3:21 back in 94 and then in 1999 put in a
3:46 which works great. Is there such a thing as a 3:46 or was it a typo
where he meant a 3:42?????
Ray
Ray & Lisa Erspamer
78 Royale Center Kitchen
TZE368V101144
Wauwatosa, Wisconsin 53226
Email: 78GMC-Royale@att.net
414-745-3188
Web Site: http://ray-lisa.page.tl/
________________________________
From: Larry <weidnerl@wwt.net>
To: gmclist@temp.gmcnet.org
Sent: Sun, October 10, 2010 8:58:21 PM
Subject: Re: [GMCnet] 3.42 ratio rear end sources?
FWIW,
There is a GMC'r by the name of John Biwersi that rebuilds 3.21's and sells them
for use in our Motohomes. A lot of guys are running his 3.21's and love them.
If you are interested in this, PM me for John's email and phone #.
--
Larry :)
78 Royale w/500 Caddy
Menomonie, WI.
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Ray Erspamer
78 GMC Royale Center Kitchen
403, 3.70 Final Drive
Holley Sniper Quadrajet EFI System,
Holley Hyperspark Ignition System
414-484-9431
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| Re: [GMCnet] 3.42 ratio rear end sources? [message #102478 is a reply to message #102468] |
Sun, 10 October 2010 21:58 |
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I've got a 3.46:1 final drive in my Palm Beach, Ray. Came from the
late Marvin Peck many years ago. I'm very happy with it.
Jim K bought all of Marvins stock several years ago.
bdub
On Sun, Oct 10, 2010 at 9:17 PM, Ray Erspamer <78gmc-royale@att.net> wrote:
> My PO's records says that he put in a 3:21 back in 94 and then in 1999 put in a
> 3:46 which works great. Is there such a thing as a 3:46 or was it a typo
> where he meant a 3:42?????
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bdub
bdub.net
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| Re: [GMCnet] 3.42 ratio rear end sources? [message #102491 is a reply to message #102442] |
Sun, 10 October 2010 23:11 |
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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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Rick,
Yup! Your Dad, Larry Turner, and I swapped a few "Viet Nam war stories" at
the luncheon. A bit different as normally it's "GMC war stories" that get
told when GMC'ers get together!;-)
Set up an eBay search for Toronado and Eldorado and check it daily that's
how I scored the switch pitch and 3.21 I have here for $200.00 in Oklahoma.
I never noticed the serial numbers of my two Avions. David Greenberg noticed
it and advised that 427 was an Eleganza.
The odds of one guy owning two sequential coaches off the Avion production
line is amazing, the fact that they're on opposite sides of the globe is
unbelievable!
BTW I have been told that the 3.21 has a bit of a positrac action due to the
planetary gear setup, I'll have to find a dirt road and give it a go and see
what happens.
Regards,
Rob M.
USAussie
-----Original Message-----
From: gmclist-bounces@temp.gmcnet.org
[mailto:gmclist-bounces@temp.gmcnet.org] On Behalf Of Rick Does
Sent: Sunday, October 10, 2010 6:44 PM
To: gmclist@temp.gmcnet.org
Subject: Re: [GMCnet] 3.42 ratio rear end sources?
Hello Rob, You met my Dad down in S.A this weekend. He had a great time
swapping stories with you.
How did you end up with VINs so close together and the coaches so far apart?
Are you looking for 100427?
One of the problems I will face is the need for a limited slip option down
the road. The final drivetrain package I envision will require one. I have
not seen references to a LSD option or availability regarding the 3.21 set.
I haven't looked real hard yet either.
As I also envision it being switch pitch I need the early Toro/Eldo tanny
anyway and am avidly searching for a good core to build. $200 would be a
purchase point for me as well. I will end up owning the 3.21 regardless if I
use it or not.
I was looking for a cheap quick gear upgrade that I could add to the stock
coach before the final transaxle gets built.
Not to be.
--
Rick Does Ft. Worth Tx
1976 Glenbrook "Some Assembly Required"
_______________________________________________
GMCnet mailing list
List Information and Subscription Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
_______________________________________________
GMCnet mailing list
List Information and Subscription Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
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] 3.42 ratio rear end sources? [message #102495 is a reply to message #102464] |
Sun, 10 October 2010 23:41 |
jimk
Messages: 6734
Registered: July 2006
Location: Belmont, CA
Karma: 9
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Senior Member |
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Look at our chart for different ratios, it gives you an idea as to how
the torque curve can help you gain power to negotiate hills .
I learned from the late Marvin Peck (Gear Master) that the most
overall funional ratio for a 26 ft. is around 3.65-3.70.
Most people need the gears at 50mph.
3,000 people can't be wrong.
Before the lower gears came out, I ran 3.21 from 1984-1993.It did not
do much to help us.
around 1994 is when the real gear ratios came out 3.50,3.60 and 3.67.
They all seemed to have some type of problem and ended up purchasing
our 3.55 as it was the only ratio we had.
We had such fantastic warrenty program, we had majority of the repair
shops purcasing them for their customers.
We still carry the best no hassel warrenty.
Once you put it in you will never need to pay for repair.
Coop,Sirum, Gradview,Golby, MGM GMC,Zeb's carry our gears.
On Sun, Oct 10, 2010 at 6:58 PM, Larry <weidnerl@wwt.net> wrote:
>
>
> FWIW,
> There is a GMC'r by the name of John Biwersi that rebuilds 3.21's and sells them for use in our Motohomes. Â A lot of guys are running his 3.21's and love them. Â If you are interested in this, PM me for John's email and phone #.
>
>
> --
> Larry  :)
> 78 Royale w/500 Caddy
> Menomonie, WI.
> _______________________________________________
> GMCnet mailing list
> List Information and Subscription Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>
--
Jim Kanomata
Applied/GMC, Fremont,CA
jimk@appliedairfilters.com
http://www.appliedgmc.com
1-800-752-7502
_______________________________________________
GMCnet mailing list
List Information and Subscription Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
Jim Kanomata
Applied/GMC
jimk@appliedairfilters.com
www.appliedgmc.com
1-800-752-7502
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| Re: [GMCnet] 3.42 ratio rear end sources? [message #102582 is a reply to message #102575] |
Mon, 11 October 2010 13:10 |
Ray Erspamer
Messages: 1707
Registered: May 2007
Location: Milwaukee Wisconsin
Karma: -3
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Senior Member |
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I have a copy of the conversion chart, I also run the 245-75-16 tires. With my
3:46 final drive, those tires put me at a 3:30 ratio.
Ray
Ray & Lisa Erspamer
78 Royale Center Kitchen
TZE368V101144
Wauwatosa, Wisconsin 53226
Email: 78GMC-Royale@att.net
414-745-3188
Web Site: http://ray-lisa.page.tl/
________________________________
From: John Wright <powerjon@chartermi.net>
To: gmclist@temp.gmcnet.org
Sent: Mon, October 11, 2010 12:52:05 PM
Subject: Re: [GMCnet] 3.42 ratio rear end sources?
Dan,
The 3.55 final with the 245/75R16E tire your final drive ratio comes
out to a 3.34.
JR Wright
On Oct 10, 2010, at 11:29 PM, Dan Gregg wrote:
>
>
> Billy, I have the 355. I run 245-75-16 tires. What do you think my
> ratio is?
> Dan
> placing local geocaches in our area
> --
> Dan & Teri Gregg
>
> http://danandteri.blogspot.com/
>
>
>
>
> _______________________________________________
> GMCnet mailing list
> List Information and Subscription Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
_______________________________________________
GMCnet mailing list
List Information and Subscription Options:
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_______________________________________________
GMCnet mailing list
List Information and Subscription Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
Ray Erspamer
78 GMC Royale Center Kitchen
403, 3.70 Final Drive
Holley Sniper Quadrajet EFI System,
Holley Hyperspark Ignition System
414-484-9431
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