West coast trip, will a 3.07 final drive be OK? not towing

RF_Burns

RF_Burns

Super Moderator
Staff member
Sep 7, 2008
5,131
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Ontario Canada
So we are thinking of doing a trip to the west coast in our '77 pb. The engine was rebuilt in 2010 by Dick Patterson and I have a Rochester TBI with
the EBL system and spark control. The transmission was replaced at the same time with a rebuilt through DickP as well.

I'm wondering if I need to worry about changing the final drive from the OEM 3.07 to a 3.55 or 3.70. We are not towing anything.

Thoughts?

Thanks

--
Bruce Hislop
ON Canada
77PB, 455 Dick P. rebuilt, DynamicEFI EBL EFI & ESC.1 ton front end
http://www.gmcmhphotos.com/photos/showphoto.php?photo=29001
My Staff says I never listen to them, or something like that
 
You will have no problems with the 3.07. I drove mine about 8000 miles all around the Southwest with the stock final drive before upgrading to a
3.70. Either way, you will probably need to downshift to pull some of the grades. I usually pull it down into 'super' at around 40 MPH and shift
back to drive at about 50.
--
Carl Stouffer
'75 ex Palm Beach
Tucson, AZ.
Chuck Aulgur Reaction Arm Disc Brakes, Quadrabags, 3.70 LSD final drive, Lenzi knuckles/hubs, Dodge Truck 16" X 8" front wheels, Rear American Eagles,
Solar battery charging. GMCSJ and GMCMI member
 
Bruce, which route are you taking? North like Interstate 80 or 90, or
South like 40? Some differences in passes and gradients exist. I have run
both ways, once with stock gearing and once with 3:70 and a 403. Both did
well. The big difference you will notice is downshift points. The stock
gearing will downshift sooner than the 3:55 will on the same grade. But,
you have more torque and horsepower than stock, so that changes the
equation a good bit. On similarly equipped coaches to yours, that I have
experience with, they don't downshift at all, and still run 10 inches of
vacuum on the steepest grades. On my 403, when my vacuum falls off below
that point, I manually downshift to avoid going into the secondaries on the
carb. My Royale is a heavy coach, and sometimes I pull a trailer full of
stuff.
Jim Hupy

> So we are thinking of doing a trip to the west coast in our '77 pb. The
> engine was rebuilt in 2010 by Dick Patterson and I have a Rochester TBI with
> the EBL system and spark control. The transmission was replaced at the
> same time with a rebuilt through DickP as well.
>
> I'm wondering if I need to worry about changing the final drive from the
> OEM 3.07 to a 3.55 or 3.70. We are not towing anything.
>
> Thoughts?
>
> Thanks
>
> --
> Bruce Hislop
> ON Canada
> 77PB, 455 Dick P. rebuilt, DynamicEFI EBL EFI & ESC.1 ton front end
> http://www.gmcmhphotos.com/photos/showphoto.php?photo=29001
> My Staff says I never listen to them, or something like that
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
 
Bruce,
Drive it out as a 3.07. If on the way you have any grade issues, take it to Applied in the Bay Area and have him put a final drive of your choice in.
While he is doing that, rent a car and check out the wine country! Beautiful country and a great time of the year to go.
Enjoy!
Scott.
--
Scott Nutter
1978 Royale Center Kitchen, Patterson 455, switch pitch tranny, 3.21 final drive, Quad bags, tankless water heater, everything Lenzi.
Houston, Texas
 
Apparently these transmissions to not like a downhill downshift. So cresting the top of the hill in drive it is better to leave it in drive and use the brakes instead of dropping down into a lower gear. This is what i have heard.

>
> So we are thinking of doing a trip to the west coast in our '77 pb. The engine was rebuilt in 2010 by Dick Patterson and I have a Rochester TBI with
> the EBL system and spark control. The transmission was replaced at the same time with a rebuilt through DickP as well.
>
> I'm wondering if I need to worry about changing the final drive from the OEM 3.07 to a 3.55 or 3.70. We are not towing anything.
>
> Thoughts?
>
> Thanks
>
> --
> Bruce Hislop
> ON Canada
> 77PB, 455 Dick P. rebuilt, DynamicEFI EBL EFI & ESC.1 ton front end
> http://www.gmcmhphotos.com/photos/showphoto.php?photo=29001
> My Staff says I never listen to them, or something like that
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org

Gary Worobec
gtw5
1973 23 GMC Glacier
1935 Dodge pickup
 
There is no need to put in a lower gear ratio, but from what we have seen
since 1990 is that the transmission hold up better.
The gas milage does not differ.
We have sold over 3,000 units, so we receive feedback.
Things like new fuel lines,fan clutch, and New fuel filters. must be done.

> Bruce,
> Drive it out as a 3.07. If on the way you have any grade issues, take it
> to Applied in the Bay Area and have him put a final drive of your choice in.
> While he is doing that, rent a car and check out the wine country!
> Beautiful country and a great time of the year to go.
> Enjoy!
> Scott.
> --
> Scott Nutter
> 1978 Royale Center Kitchen, Patterson 455, switch pitch tranny, 3.21 final
> drive, Quad bags, tankless water heater, everything Lenzi.
> Houston, Texas
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>

--
Jim Kanomata
Applied/GMC, Newark,CA
jimk
http://www.appliedgmc.com
1-800-752-7502
 
No, use the gears to go up the hill and down the hill. Use the brakes to limit engine speeds only. If you are worried about downshifting then pull the
hill in S and leave it there for the way down. I have done long grades with 3.07 and now have 3.42. Less need to use S as much and seems happier
--
John Lebetski
Woodstock, IL
77 Eleganza II
 
I don’t agree. I used a 3.07 for about 30 years before buying my 3.55 and I downshifted it for downhills all the time.

Emery Stora
77 Kingsley
Frederick, CO

>
> Apparently these transmissions to not like a downhill downshift. So cresting the top of the hill in drive it is better to leave it in drive and use the brakes instead of dropping down into a lower gear. This is what i have heard.
>

>>
>> So we are thinking of doing a trip to the west coast in our '77 pb. The engine was rebuilt in 2010 by Dick Patterson and I have a Rochester TBI with
>> the EBL system and spark control. The transmission was replaced at the same time with a rebuilt through DickP as well.
>>
>> I'm wondering if I need to worry about changing the final drive from the OEM 3.07 to a 3.55 or 3.70. We are not towing anything.
>>
>> Thoughts?
>>
>> Thanks
>>
>> --
>> Bruce Hislop
>> ON Canada
>> 77PB, 455 Dick P. rebuilt, DynamicEFI EBL EFI & ESC.1 ton front end
>> http://www.gmcmhphotos.com/photos/showphoto.php?photo=29001
>> My Staff says I never listen to them, or something like that
>>
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
>> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
> Gary Worobec
> gtw5
> 1973 23 GMC Glacier
> 1935 Dodge pickup
>
>
>
>
>
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
 
I am not sure using the transmission as a grade retard will have much of an
effect on longevity. I have always used mine that way, much more so before
I changed to 3:70 final drive gears. But, I only have 100 thousand miles on
this one.
Jim Hupy

> I don’t agree. I used a 3.07 for about 30 years before buying my 3.55 and
> I downshifted it for downhills all the time.
>
> Emery Stora
> 77 Kingsley
> Frederick, CO
>

> >
> > Apparently these transmissions to not like a downhill downshift. So
> cresting the top of the hill in drive it is better to leave it in drive and
> use the brakes instead of dropping down into a lower gear. This is what i
> have heard.
> >

> >>
> >> So we are thinking of doing a trip to the west coast in our '77 pb.
> The engine was rebuilt in 2010 by Dick Patterson and I have a Rochester TBI
> with
> >> the EBL system and spark control. The transmission was replaced at the
> same time with a rebuilt through DickP as well.
> >>
> >> I'm wondering if I need to worry about changing the final drive from
> the OEM 3.07 to a 3.55 or 3.70. We are not towing anything.
> >>
> >> Thoughts?
> >>
> >> Thanks
> >>
> >> --
> >> Bruce Hislop
> >> ON Canada
> >> 77PB, 455 Dick P. rebuilt, DynamicEFI EBL EFI & ESC.1 ton front end
> >> http://www.gmcmhphotos.com/photos/showphoto.php?photo=29001
> >> My Staff says I never listen to them, or something like that
> >>
> >> _______________________________________________
> >> GMCnet mailing list
> >> Unsubscribe or Change List Options:
> >> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
> >
> > Gary Worobec
> > gtw5
> > 1973 23 GMC Glacier
> > 1935 Dodge pickup
> >
> >
> >
> >
> >
> >
> > _______________________________________________
> > GMCnet mailing list
> > Unsubscribe or Change List Options:
> > http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
 
We have driven all over the West Coast & Rockies with a stock final drive. About 280000 miles on the 77 Eleganza before putting in a Manny Power
Drive chain when he did a precautionary transmission rebuild. You may spend a little more time in 2nd gear in the mountains. My rule of thumb is to
manually shift down before 45mph (do not wait for it to shift itself). Do the same thing on steep downgrades, shift in to 2nd before it gets above
45, just don't wait to pull it down when you are going downhill fast. You may not be the first to the top or the bottom, but you should still will be
running OK when you get back to the Flatlands. Just What We Did.
--
John Shutzbaugh, Vacaville, CA, ncserv;
77 Eleganza, bought it new, can't blame PO, and
78 Buskirk stretch, "What were we thinking?"
 
JimH, we will likely do Canadian Rockies out to Vancouver and over to the island. Then back through the mid States, not enough time to go the southern
route back this time.
The EBLs deceleration fuel cut off keeps the coach from speeding up on any declines so far.

--
Bruce Hislop
ON Canada
77PB, 455 Dick P. rebuilt, DynamicEFI EBL EFI & ESC.1 ton front end
http://www.gmcmhphotos.com/photos/showphoto.php?photo=29001
My Staff says I never listen to them, or something like that
 
Agreed, pulling it down a gear while going downhill is an issue according to Manny.

>
> We have driven all over the West Coast & Rockies with a stock final drive. About 280000 miles on the 77 Eleganza before putting in a Manny Power
> Drive chain when he did a precautionary transmission rebuild. You may spend a little more time in 2nd gear in the mountains. My rule of thumb is to
> manually shift down before 45mph (do not wait for it to shift itself). Do the same thing on steep downgrades, shift in to 2nd before it gets above
> 45, just don't wait to pull it down when you are going downhill fast. You may not be the first to the top or the bottom, but you should still will be
> running OK when you get back to the Flatlands. Just What We Did.
> --
> John Shutzbaugh, Vacaville, CA, ncserv;
> 77 Eleganza, bought it new, can't blame PO, and
> 78 Buskirk stretch, "What were we thinking?"
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org

Gary Worobec
gtw5
1973 23 GMC Glacier
1935 Dodge pickup
 
The list has been over this, don't just pop it into s at high speed, but
slow to a reasonable point, shift to s, and then let it coast back to to
the speed it holds it at.

Or so I remember. I sur wouldn't use stock brakes to control my speed all
the way down our big grades.

> Agreed, pulling it down a gear while going downhill is an issue according
> to Manny.
>
> > On Mar 15, 2018, at 6:40 PM, John Shutzbaugh

> >
> > We have driven all over the West Coast & Rockies with a stock final
> drive. About 280000 miles on the 77 Eleganza before putting in a Manny
> Power
> > Drive chain when he did a precautionary transmission rebuild. You may
> spend a little more time in 2nd gear in the mountains. My rule of thumb is
> to
> > manually shift down before 45mph (do not wait for it to shift itself).
> Do the same thing on steep downgrades, shift in to 2nd before it gets above
> > 45, just don't wait to pull it down when you are going downhill fast.
> You may not be the first to the top or the bottom, but you should still
> will be
> > running OK when you get back to the Flatlands. Just What We Did.
> > --
> > John Shutzbaugh, Vacaville, CA, ncserv;
> > 77 Eleganza, bought it new, can't blame PO, and
> > 78 Buskirk stretch, "What were we thinking?"
> >
> > _______________________________________________
> > GMCnet mailing list
> > Unsubscribe or Change List Options:
> > http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
> Gary Worobec
> gtw5
> 1973 23 GMC Glacier
> 1935 Dodge pickup
>
>
>
>
>
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
 
RIGHT WAY TO DO IT!! Then use the brakes to slow down below a safe speed
when you're going too fast, then coast some more.

RonC

The list has been over this, don't just pop it into s at high speed, but
slow to a reasonable point, shift to s, and then let it coast back to to
the speed it holds it at.

Or so I remember. I sur wouldn't use stock brakes to control my speed all
the way down our big grades.
 
I plan on installing Dave Lenzi's mid axle discs this spring. Already have the larger 1 ton front brakes so I'm hoping the brakes will be good.

Sounds like I'm good with the OEM 3.07 final drive.

Thanks guys.

--
Bruce Hislop
ON Canada
77PB, 455 Dick P. rebuilt, DynamicEFI EBL EFI & ESC.1 ton front end
http://www.gmcmhphotos.com/photos/showphoto.php?photo=29001
My Staff says I never listen to them, or something like that
 
Nothing like a 3.70.

> I plan on installing Dave Lenzi's mid axle discs this spring. Already have
> the larger 1 ton front brakes so I'm hoping the brakes will be good.
>
> Sounds like I'm good with the OEM 3.07 final drive.
>
> Thanks guys.
>
>
> --
> Bruce Hislop
> ON Canada
> 77PB, 455 Dick P. rebuilt, DynamicEFI EBL EFI & ESC.1 ton front end
> http://www.gmcmhphotos.com/photos/showphoto.php?photo=29001
> My Staff says I never listen to them, or something like that
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
 
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