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Home » Public Forums » GMCnet » Speedometer Gear Combinations (What speedometer Gear Combinations work well with the 3.70 upgrade?)
Speedometer Gear Combinations [message #316706] Thu, 27 April 2017 15:44 Go to next message
RoadWarrior is currently offline  RoadWarrior   United States
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OK, my PO added the 3.70 gears to my coach (can't hate him for that). I want to get my speedometer to read correctly and was wondering what speedometer drive, and driven gear combinations anyone has used successfully?
Re: Speedometer Gear Combinations [message #316707 is a reply to message #316706] Thu, 27 April 2017 15:52 Go to previous messageGo to next message
A Hamilto is currently offline  A Hamilto   United States
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RoadWarrior wrote on Thu, 27 April 2017 15:44
OK, my PO added the 3.70 gears to my coach (can't hate him for that). I want to get my speedometer to read correctly and was wondering what speedometer drive, and driven gear combinations anyone has used successfully?
http://www.appliedgmc.com/prod.itml/icOid/1374
Re: [GMCnet] Speedometer Gear Combinations [message #316709 is a reply to message #316706] Thu, 27 April 2017 15:51 Go to previous messageGo to next message
James Hupy is currently offline  James Hupy   United States
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There is a gearbox that Jim K. supplies with the new ratio final drive that
mounts on the speedometer drive that changes the gear ratio to feed the
speedometer IF NO ONE HAS MESSED WITH the original gears that came with the
3:07 final drive and stock TM-425. Give him a call to see what you might
have available.
Jim Hupy
Salem, OR
78 GMC Royale 403 w/3:70 final drive and the corrected speedometer gearbox.

On Thu, Apr 27, 2017 at 1:44 PM, John Watkins wrote:

> OK, my PO added the 3.70 gears to my coach (can't hate him for that). I
> want to get my speedometer to read correctly and was wondering what
> speedometer drive, and driven gear combinations anyone has used
> successfully?
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
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Re: [GMCnet] Speedometer Gear Combinations [message #316712 is a reply to message #316709] Thu, 27 April 2017 16:05 Go to previous messageGo to next message
RoadWarrior is currently offline  RoadWarrior   United States
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I know that option is available, but it isn't a big job to pull the governor and replace the speedometer drive gear. Also, that little reducer is likely to get cooked by the heat of the headers.
Re: [GMCnet] Speedometer Gear Combinations [message #316713 is a reply to message #316712] Thu, 27 April 2017 16:15 Go to previous messageGo to next message
James Hupy is currently offline  James Hupy   United States
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I have been running one of them for a long time (years) with two cross
country trips included. I run Doug Thorley Headers on a 403 Olds with a
heavy 78 Royale Coach frequently pulling a trailer. No problems yet with
the gearbox. I am not sure that you can get the exact gear any longer that
will be spot on with only one gear changed if you go into the transmission.
But, Jim K can tell you for sure, and he has a toll free phone number. All
it will cost you is your time. If you are running headers and they are not
the Manny T ones, you will have to pull the headers on that side of the
engine to pull the governor. But, it is your time and money, and this is
America, land of the Free Choices.
Jim Hupy
Salem, OR
78 GMC Royale 403

On Thu, Apr 27, 2017 at 2:05 PM, John Watkins wrote:

> I know that option is available, but it isn't a big job to pull the
> governor and replace the speedometer drive gear. Also, that little reducer
> is
> likely to get cooked by the heat of the headers.
>
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
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>
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Re: [GMCnet] Speedometer Gear Combinations [message #316714 is a reply to message #316713] Thu, 27 April 2017 16:55 Go to previous messageGo to next message
Harry is currently offline  Harry   Canada
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There was a lad in Florida that had gear reducers for this purpose.
Try Ron 727 410 6352
Re: [GMCnet] Speedometer Gear Combinations [message #316717 is a reply to message #316714] Thu, 27 April 2017 18:37 Go to previous messageGo to next message
jimk is currently offline  jimk   United States
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We carry the reducers as we need to supply them with our 3.55,3.70,4.10 and Limited Slip Differentials

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________________________________
From: Gmclist on behalf of David H.Jarvis
Sent: Thursday, April 27, 2017 2:55:36 PM
To: gmclist@list.gmcnet.org
Subject: Re: [GMCnet] Speedometer Gear Combinations

There was a lad in Florida that had gear reducers for this purpose.
Try Ron 727 410 6352


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Jim Kanomata
Applied/GMC
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Re: [GMCnet] Speedometer Gear Combinations [message #316718 is a reply to message #316712] Thu, 27 April 2017 18:41 Go to previous messageGo to next message
jimk is currently offline  jimk   United States
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No need to disturb the Gov to remove the speedo gear.


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________________________________
From: Gmclist on behalf of John Watkins
Sent: Thursday, April 27, 2017 2:05:10 PM
To: gmclist@list.gmcnet.org
Subject: Re: [GMCnet] Speedometer Gear Combinations

I know that option is available, but it isn't a big job to pull the governor and replace the speedometer drive gear. Also, that little reducer is
likely to get cooked by the heat of the headers.


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Jim Kanomata
Applied/GMC
jimk@appliedairfilters.com
www.appliedgmc.com
1-800-752-7502
Re: [GMCnet] Speedometer Gear Combinations [message #316719 is a reply to message #316712] Thu, 27 April 2017 18:45 Go to previous messageGo to next message
jimk is currently offline  jimk   United States
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Headers do not do much to damage the gear.
Heat effects the cable and jams up and strips the gear.
Know this from working on coaches

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________________________________
From: Gmclist on behalf of John Watkins
Sent: Thursday, April 27, 2017 2:05:10 PM
To: gmclist@list.gmcnet.org
Subject: Re: [GMCnet] Speedometer Gear Combinations

I know that option is available, but it isn't a big job to pull the governor and replace the speedometer drive gear. Also, that little reducer is
likely to get cooked by the heat of the headers.


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Jim Kanomata
Applied/GMC
jimk@appliedairfilters.com
www.appliedgmc.com
1-800-752-7502
Re: [GMCnet] Speedometer Gear Combinations [message #316720 is a reply to message #316709] Thu, 27 April 2017 18:47 Go to previous messageGo to next message
jimk is currently offline  jimk   United States
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We end up supplying special ratio when people make changes without knowing

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________________________________
From: Gmclist on behalf of James Hupy
Sent: Thursday, April 27, 2017 1:51:23 PM
To: gmclist@list.gmcnet.org
Subject: Re: [GMCnet] Speedometer Gear Combinations

There is a gearbox that Jim K. supplies with the new ratio final drive that
mounts on the speedometer drive that changes the gear ratio to feed the
speedometer IF NO ONE HAS MESSED WITH the original gears that came with the
3:07 final drive and stock TM-425. Give him a call to see what you might
have available.
Jim Hupy
Salem, OR
78 GMC Royale 403 w/3:70 final drive and the corrected speedometer gearbox.

On Thu, Apr 27, 2017 at 1:44 PM, John Watkins wrote:

> OK, my PO added the 3.70 gears to my coach (can't hate him for that). I
> want to get my speedometer to read correctly and was wondering what
> speedometer drive, and driven gear combinations anyone has used
> successfully?
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
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Jim Kanomata
Applied/GMC
jimk@appliedairfilters.com
www.appliedgmc.com
1-800-752-7502
Re: [GMCnet] Speedometer Gear Combinations [message #316722 is a reply to message #316706] Thu, 27 April 2017 18:51 Go to previous messageGo to next message
jimk is currently offline  jimk   United States
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Just call me and I will get data from you and supply the correct ratio

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________________________________
From: Gmclist on behalf of John Watkins
Sent: Thursday, April 27, 2017 1:44:36 PM
To: gmclist@list.gmcnet.org
Subject: [GMCnet] Speedometer Gear Combinations

OK, my PO added the 3.70 gears to my coach (can't hate him for that). I want to get my speedometer to read correctly and was wondering what
speedometer drive, and driven gear combinations anyone has used successfully?

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Jim Kanomata
Applied/GMC
jimk@appliedairfilters.com
www.appliedgmc.com
1-800-752-7502
Re: [GMCnet] Speedometer Gear Combinations [message #316732 is a reply to message #316706] Fri, 28 April 2017 00:09 Go to previous messageGo to next message
jimk is currently offline  jimk   United States
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Just call me as we can solve it

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________________________________
From: Gmclist on behalf of John Watkins
Sent: Thursday, April 27, 2017 1:44:36 PM
To: gmclist@list.gmcnet.org
Subject: [GMCnet] Speedometer Gear Combinations

OK, my PO added the 3.70 gears to my coach (can't hate him for that). I want to get my speedometer to read correctly and was wondering what
speedometer drive, and driven gear combinations anyone has used successfully?

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Jim Kanomata
Applied/GMC
jimk@appliedairfilters.com
www.appliedgmc.com
1-800-752-7502
Re: Speedometer Gear Combinations [message #316733 is a reply to message #316706] Fri, 28 April 2017 08:12 Go to previous messageGo to next message
skip2 is currently offline  skip2   United States
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I ordered heat shield tubing, I believe from Sunmmit or Jegs their private brand less expensive different sizes available, and put around speedo cables and anything in the area of the headers, so far so good after I melted down a speedo cable.
Skip Hartline


74 Canyon Lands, FiTech, 3.7 FD LSD, Manny Tranny, Springfield Distributor, 2001 Chevy Tracker Ragtop Towd
Re: [GMCnet] Speedometer Gear Combinations [message #316736 is a reply to message #316733] Fri, 28 April 2017 08:42 Go to previous messageGo to next message
jimk is currently offline  jimk   United States
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You need to strap the cable away from the exaust

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________________________________
From: Gmclist on behalf of Skip Hartline
Sent: Friday, April 28, 2017 6:12:51 AM
To: gmclist@list.gmcnet.org
Subject: Re: [GMCnet] Speedometer Gear Combinations

I ordered heat shield tubing, I believe from Sunmmit or Jegs their private brand less expensive different sizes available, and put around speedo
cables and anything in the area of the headers, so far so good after I melted down a speedo cable.
Skip Hartline

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Jim Kanomata
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www.appliedgmc.com
1-800-752-7502
Re: [GMCnet] Speedometer Gear Combinations [message #316747 is a reply to message #316736] Fri, 28 April 2017 12:04 Go to previous messageGo to next message
Matt Colie is currently offline  Matt Colie   United States
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I don't think you want to change the governor gear. If you do that, you will be moving the shift points up the engine's torque curve and that is one thing you really don't want to do as it would negate some of the value of the higher numerical ratio final drive.

Matt


Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit
Re: Speedometer Gear Combinations [message #316748 is a reply to message #316706] Fri, 28 April 2017 12:46 Go to previous messageGo to next message
Larry is currently offline  Larry   United States
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These GPS Speedo's are pricey, but sure work nice,

https://www.horsepowerfreaks.com/-p-150899736.html?gclid=CNfnvO_Xx9MCFddWDQodQGsOzA


Larry Smile
78 Royale w/500 Caddy
Menomonie, WI.
Re: [GMCnet] Speedometer Gear Combinations [message #316749 is a reply to message #316748] Fri, 28 April 2017 13:12 Go to previous messageGo to next message
Vern Crawford is currently offline  Vern Crawford   United States
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I picked up a Garmin GPS on sale for something like $129 a few years ago.
It has a very precise digital speedometer. Additionally, for most roads
(90%+) it displays the speed limits as well. It also can calculate routes,
AND does a pretty good job of keeping me on the correct roads.

Hugs,
Vern

Currently at the GMC Classics Rally in Bandera, Texas
On Fri, Apr 28, 2017 at 12:52 PM Larry wrote:

> These GPS Speedo's are pricey, but sure work nice,
>
>
> https://www.horsepowerfreaks.com/-p-150899736.html?gclid=CNfnvO_Xx9MCFddWDQodQGsOzA
> --
> Larry
> 78 Royale w/500 Caddy
> Menomonie, WI.
>
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--
Vern Crawford
2013-2014 Past-President
Hill Country Chapter
Texas Master Naturalist

155 J-J Lane
Center Point, TX 78010
(830) 634-2576 home
(618) 203-8296 cell
VernCrawford@GMail.Com

[image: Texas Master Naturalist_small]
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Re: [GMCnet] Speedometer Gear Combinations [message #316793 is a reply to message #316747] Sat, 29 April 2017 13:14 Go to previous message
RoadWarrior is currently offline  RoadWarrior   United States
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I at least need to inspect the governor drive gear (speedometer bouncing). The speedometer "Drive" gear is at the top of the governor, not the one at the bottom and only drives the speedometer "Driven) gear. The speedometer gears don't affect shift points. Other than the speedometers reading.
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