Home » Public Forums » GMCnet » ~ Final Drive ~
| ~ Final Drive ~ [message #222166] |
Thu, 12 September 2013 18:42  |
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jaholland
Messages: 565
Registered: June 2010
Location: Sweet Home Alebamy
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I have a '78 Eleganza II that came with
the 403 Motor /307 Final Drive set up ~
After years struggling up slight inclines
while pulling our towd caused me to change
out my 307 final drive for a 370 and I got
much more pulling power, more gas mileage
and better overall performance .
~> {my only regret is no Posi-Traction}
A fellow GMC Motorhome owner recently
asked me the following question;
"What About Installing A 410 Final Drive
On THE GMC Motorhome 403 MOTOR and
307 Final Drive Setup" ?
So Now I Am Asking For Your Input ~
What would be the advantage of the 410
VS
What would be the advantage of the 370
~ Joe ~
/_]*[__][] *[__|] ~ * '73 TZE063V101887 "
"
O----------OO--]* ~ '78 TZE168V100234 "
"
" Joe & Lavelle " "
"
'sweet home alebamy'
[Updated on: Thu, 12 September 2013 18:56] Report message to a moderator |
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| Re: ~ Final Drive ~ [message #222183 is a reply to message #222166] |
Thu, 12 September 2013 19:46  |
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Matt Colie
Messages: 8547
Registered: March 2007
Location: S.E. Michigan
Karma: 7
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| jaholland wrote on Thu, 12 September 2013 19:42 |
I have a '78 Eleganza II that came with the 403 Motor /307 Final Drive set up ~
After years struggling up slight inclines while pulling our towd caused me to change out my 307 final drive for a 370 and I got much more pulling power, more gas mileage and better overall performance .
~> {my only regret is no Posi-Traction}
A fellow GMC Motorhome owner recently asked me the following question;
"What About Installing A 410 Final Drive On THE GMC Motorhome 403 MOTOR and 307 Final Drive Setup" ?
So Now I Am Asking For Your Input ~
What would be the advantage of the 410
VS
What would be the advantage of the 370
~ Joe ~
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Joe,
I was an automotive engineer a lot of my working life.
The plan is to get the expected road speed to land the engine in the middle of its torque curve. Hitting a little high is no big thing, but problem is that John Q Public has been convinced buy pre-WWII data that slower turning engines are more efficient and last longer.
That may have been true then, but I do know it is not now. What really tears up an engine is lugging. (Translation: Asking an engine for maximum torque below its peak torque crankshaft speed.)
I do not have all the information I would like to have. (It seldom that an engineer actually does.) But, from what I know, I would have to think that a 403 would love a 4.10. That would put road speed in the middle of the only 403 torque curve I have ever seen. That would lower the required BMEP (the average cylinder pressure that makes the torque) and lower the load on the piston rings (they would last longer) and the additional speed would make the bearings last longer (and they wouldn't get hammered either).
If there is an actual advantage a 4.10 has over a 3.70, I would have to see real numbers to confirm it, but I can pretty much assure you that it would not hurt anything.
The only advantage that I can see that a 3.70 would have is that JimK has supplied a whole bunk of them and not had problems.
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
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| Re: ~ Final Drive ~ [message #222201 is a reply to message #222183] |
Thu, 12 September 2013 21:21 |
A Hamilto
Messages: 4508
Registered: April 2011
Karma: 39
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| Matt Colie wrote on Thu, 12 September 2013 19:46 |
... from what I know, I would have to think that a 403 would love a 4.10. That would put road speed in the middle of the only 403 torque curve I have ever seen. ...
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What's "road speed"?
[Updated on: Thu, 12 September 2013 21:22] Report message to a moderator |
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| Re: ~ Final Drive ~ [message #222244 is a reply to message #222201] |
Fri, 13 September 2013 07:47 |
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jaholland
Messages: 565
Registered: June 2010
Location: Sweet Home Alebamy
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Bob Dunahugh wrote
Messages: 153
Registered: October 2010
Location: Cedar Rapids, IA
Senior Member
{quote }
Have a 78 Royale, 403, and the 3:70.
Sometimes my GVW is in the 20,000 lbs range.
Depending on the trailer I'm pulling.
You've herd about how the short stroke,
big bore 403 comes into it's own above 3,100 rpm's.
So, so true, When I got the 3:70 in 2004.
Best change that I ever made to that GMC.
The 4:10 wasn't out yet. Engine, and trans run cooler,
and my mileage went up. ( Not a lot )
Thinking of selling the 3:70. And going to the 4:10.
Most 1 ton trucks run 3:70 tops, to 4:88.
You could keep it above 3,100 RPM,s more of the time.
When I'm in the mountains. I shift it down. And run it up to 4,500 RPM's. And just leave it there.
The trans at that point is running a lot of fluid to that cooler.
And the load on pistons, rings, and bearings is reduced.
There is 145,000. miles on the clock.
Runs great.
Bob Dunahugh
GMCMI Member
78 Royale4 Yenko Chevrolet's (unquote}
/_]*[__][] *[__|] ~ * '73 TZE063V101887 "
"
O----------OO--]* ~ '78 TZE168V100234 "
"
" Joe & Lavelle " "
"
'sweet home alebamy'
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| Re: ~ Final Drive ~ [message #222385 is a reply to message #222201] |
Sat, 14 September 2013 08:18 |
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Matt Colie
Messages: 8547
Registered: March 2007
Location: S.E. Michigan
Karma: 7
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| A Hamilto wrote on Thu, 12 September 2013 22:21 |
| Matt Colie wrote on Thu, 12 September 2013 19:46 |
... from what I know, I would have to think that a 403 would love a 4.10. That would put road speed in the middle of the only 403 torque curve I have ever seen. ...
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What's "road speed"?
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A,
Road speed is a term used loosely in automotive engineering to describe the velocity of a particular vehicle in its expected service. One would not use the same design speed for a Corvette that one might use for a C3500 chassis.
For most of us with old GMCs, road speed is probably 60~65, but if you have a twin turbo Cadillac, it might just be 80~85 and in that case, I thing a high numerical final drive might be ill-advised.
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
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| Re: [GMCnet] ~ Final Drive ~ [message #222412 is a reply to message #222407] |
Sat, 14 September 2013 10:57 |
James Hupy
Messages: 6806
Registered: May 2010
Karma: -62
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Another thing to consider when regearing the GMC is driving into constant
headwinds. With my 78 Royale that is quite heavy and equipped with 3:07
gearing battling headwinds would sometimes require that I shift into 2nd to
maintain 55 mph. Running from Fresno to Weed California, a trip that we
take frequently, that would just suck the fuel down. Now with the 3:70
gearing, I can maintain 60 - 65 mph into the wind and still run on the
primaries at about 12 - 14 inches of vacuum. Way better fuel mileage to be
sure. Same thing with the Columbia Gorge in Oregon. Headwinds there are
frequently 50 - 60 MPH. 200 miles in that stuff ain't fun. My overall fuel
economy is the same or slightly better with the lower gearing, and the
driveability is much improved.
Jim Hupy
Salem, OR
78 GMC Royale 403
On Sat, Sep 14, 2013 at 8:42 AM, A. <markbb1@netzero.com> wrote:
>
>
> Matt Colie wrote on Sat, 14 September 2013 08:18
> > A,
> >
> > Road speed is a term used loosely in automotive engineering to describe
> the velocity of a particular vehicle in its expected service. One would
> not use the same design speed for a Corvette that one might use for a C3500
> chassis.
> >
> > For most of us with old GMCs, road speed is probably 60~65, but if you
> have a twin turbo Cadillac, it might just be 80~85 and in that case, I
> thing a high numerical final drive might be ill-advised.
> >
> > Matt
> 65 is a good speed. Even in the places where the speed limit is 70 or 75
> I just go 65 in the slow lane in the car. Gas mileage in passenger cars
> drops off a cliff at speeds higher than that. On a 700 mile trip, it adds
> up to almost 20% more for fuel in the CFO's Ford Freestyle.
>
> Geared the way it is, it would not surprise me if the GMC got about the
> same at 70 or 75 as it does at 65.
> --
> '73 23' Sequoia For Camping
> '73 23' CanyonLands For Sale
> UA (Upper Alabama)
> "Time is money. If you use YOUR time, you get to keep YOUR money."
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| Re: [GMCnet] ~ Final Drive ~ [message #224893 is a reply to message #222412] |
Tue, 08 October 2013 17:21 |
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jaholland
Messages: 565
Registered: June 2010
Location: Sweet Home Alebamy
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~> 307 / 410 Final Drive <~
I have an extra 307 Final Drive
and would like to change it into
a limited slip 410 Final Drive for
installation in our 78 Eleganza II ~
Dumb me wants to know just what all
I will need to accomplish this since
I seem to have more time than money ?
~ Joe ~
/_]*[__][] *[__|] ~ * '73 TZE063V101887 "
"
O----------OO--]* ~ '78 TZE168V100234 "
"
" Joe & Lavelle " "
"
'sweet home alebamy'
[Updated on: Tue, 08 October 2013 17:22] Report message to a moderator |
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| Re: [GMCnet] ~ Final Drive ~ [message #224901 is a reply to message #224898] |
Tue, 08 October 2013 18:36 |
powerjon
Messages: 2446
Registered: January 2004
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Better work on the money part as the parts will cost you almost as much as the finished product and thats if Jim K would sell them to you separately and you will still have no warrantee also. The warrantee is pretty darn good!
JR Wright
On Oct 8, 2013, at 7:17 PM, James Hupy <jamesh1296@gmail.com> wrote:
> You will need a case spreader, and a carrier holding fixture to hold the
> carrier stationary while you torque the cap screws holding the ring gear.
> Probably also will need some different shims to adjust ring gear to pinion
> clearance. Might also need to shim the pinion depth. Dial indicator,
> prussian blue or white lead to check tooth contact. Knowledge on how to do
> all this stuff is also helpful. Some cases will need to be ground slightly
> to clear the new ring gear and carrier assembly. Other than that, it's a
> piece of cake. Oh, I forgot, you need to r & r the final drive.
> Jim Hupy
> Salem, Or
> 78 gmc Royale 403.
> On Oct 8, 2013 3:21 PM, "J A Holland" <acts238bishop@yahoo.com> wrote:
>
>>
>>
>> ~> 307 / 410 Final Drive <~
>>
>> I have an extra 307 Final Drive
>> and would like to change it into
>> a limited slip 410 Final Drive and
>> install it in our 78 Eleganza II ~
>>
>> Dumb me wants to know just what all
>> I will need to accomplish this since
>> I seem to have more time than money ?
>>
>> ~ Joe ~
>>
>> --
>> /_]*[__][] *[__|] ~ * '73 TZE063V101887 ""
>> O----------OO--]* ~ '78 TZE168V100234 ""
>> " Joe & Lavelle " ""
>> 'sweet home alebamy'
>>
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
>> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
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> _______________________________________________
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JR Wright
GMC Great Laker MHC
GMC Eastern States
GMCMHI
78 Buskirk 30' Stretch
1975 Avion (Under Reconstruction)
Michigan
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J.R. Wright
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GMC Eastern States
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78 30' Buskirk Stretch
75 Avion Under Reconstruction
Michigan
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| Re: ~ Final Drive ~ [message #224934 is a reply to message #222166] |
Wed, 09 October 2013 01:50 |
jim kanomata
Messages: 257
Registered: March 2007
Location: fremont,ca
Karma: 12
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We have supplied the 4.10 gear assembly to 20 people.
They call out the ratio and I sold it to them.
Only reason I do not push that ratio is the possibility of noise.
The final drive unit is bolted to the engine and your riding on top.
I have 2 locations that assemble them and it is not as easy to do when it comes to doing it so you do not end up with a noisy unit.
One can see that the ratio is a great ratio for driving between 55-65mph.
Maybe we will put in a 4.10 with limited slip unit on our 403 powered unit and try it out on our own and see how it works and noise issue.
Jim Kanomata
Applied/GMC, Fremont,CA
jimk@appliedairfilters.com
http://www.appliedgmc.com
1-800-752-7502
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| Re: [GMCnet] ~ Final Drive ~ [message #224947 is a reply to message #224939] |
Wed, 09 October 2013 09:28 |
jhbridges
Messages: 8412
Registered: May 2011
Location: Braselton ga
Karma: -74
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Take a look at what Go-Mads are selling for these days.....
--johnny\
--------------------------------------------
On Wed, 10/9/13, Jim Galbavy <j.galbavy@att.net> wrote:
Subject: Re: [GMCnet] ~ Final Drive ~
To: gmclist@temp.gmcnet.org
Date: Wednesday, October 9, 2013, 1:20 PM
Back in my college days, I had a '57 Chevy Nomad that
sported a 265 ci V/8 and a 4:11 rear. Great for towing stock
cars but high revving on the highway topping out about
65mph.
jim galbavy
'73 x-CL ANNIE
Lake Mary, Fl
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Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
I forgive them all, save those who hurt the dogs. They must answer to me in hell
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| Re: ~ Final Drive ~ [message #224971 is a reply to message #224934] |
Wed, 09 October 2013 11:32 |
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jaholland
Messages: 565
Registered: June 2010
Location: Sweet Home Alebamy
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| jim kanomata wrote on Wed, 09 October 2013 01:50 |
We have supplied the 4.10 gear assembly to 20 people.
They call out the ratio and I sold it to them.
Only reason I do not push that ratio is the possibility of noise.
The final drive unit is bolted to the engine and your riding on top.
I have 2 locations that assemble them and it is not as easy to do
when it comes to doing it so you do not end up with a noisy unit.
One can see that the ratio is a great ratio for driving between
55-65mph.
Maybe we will put in a 4.10 with limited slip unit
on our 403 powered unit and try it out on our own
and see how it works and noise issue.
|
+ + + + + + + + + +
OR
Since I like the 2 lane hiways and biways
most of my driving is in the 55/65mph range
JUST MAYBE
we could work out some kind of a test deal with the
"Master" 'Kanomaters'
by putting the 4.10 / limited slip unit on our 403
powered Eleganza II
I could try it out to see just how Well and Quiet
The Limited Slip 410 Final Drive Really Is ~
~ JOE ~
/_]*[__][] *[__|] ~ * '73 TZE063V101887 "
"
O----------OO--]* ~ '78 TZE168V100234 "
"
" Joe & Lavelle " "
"
'sweet home alebamy'
[Updated on: Wed, 09 October 2013 21:21] Report message to a moderator |
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| Re: ~ Final Drive ~ [message #224997 is a reply to message #222166] |
Wed, 09 October 2013 14:31 |
Cadillackeeper
Messages: 464
Registered: October 2012
Location: Fort Lauderdale
Karma: 1
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I will say this my 67 Eldo is 3:21.At 100mph I am at almost 4000rpm.I wish I had fourth gear in the trans.4:10/11 is for Drag Racing.As far as limited slip,it is already!
If one gets stuck going up an icy hill,kitty litter one wheel and the other will spin,and If I really floor it and hold it down both tires will spin,however this is at the end of its rope when its spinning both tires and I don't advise 4500 rpm burnouts.When one has that kind of power it is difficult not to use it,wisely or unwise.Like having a suzuki hyabusa and going 20 through a school zone.If they had it full posi it would burn the tire every time you make a turn,early versions of the gm FWD had tortional dampeners in the driveshaft to take up the slack instead
of burning the tire,cost too much for them to keep using it so the tire burns as it is!
77 455 Elaganza II and 67 Animal, Built 500 Powered Eldo
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