your ideas on best all around rear axle gears

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markmitchinnh
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your ideas on best all around rear axle gears

Post by markmitchinnh »

I would like to know what you guys think about what the best all around gear ratio for traveling and general driving around.
Recently bought a 1989 Astro RS from Florida. Replaced stock engine witha 1997 5.7 vortec with TBI and replaced transmission with rebuilt 700R4 with mild shift kit.
Bought on Monday the 16th of April 2012
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Re: your ideas on best all around rear axle gears

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1Gary
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Re: your ideas on best all around rear axle gears

Post by 1Gary »

Copied that chart Timeless.It does leave alot to be questioned when it come to a torque/power curve.But is a ballpark ref.

I think a good all around gear is 3.73's.That is taking into account you V8 conversion as well.
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1989 Astro-Ole Yellar cancelled-still selling off parts
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1994 Astro LT RWD W4.3 rod knock RIP
1982 Winnebago single rear wheel-Chevy 350 Scraped 1/28/13-broken dreams......


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Re: your ideas on best all around rear axle gears

Post by MountainManJoe »

Gary, the numbers in the boxes are engine RPM with a 1:1 transmission ratio going about 65mph.

You decide where that fits into your performance curve.
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Re: your ideas on best all around rear axle gears

Post by 1Gary »

Oh.it didn't say that. #-o :muhaha:
1979 Malibu drag race only car
1999 Sonoma 4.3 5 speed-Rufus
1989 Astro-Ole Yellar cancelled-still selling off parts
1985 Astro-shop van R.I.P. my friend
1994 Astro LT RWD W4.3 rod knock RIP
1982 Winnebago single rear wheel-Chevy 350 Scraped 1/28/13-broken dreams......


Rochester,NY

LiftedAWDAstro
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Re: your ideas on best all around rear axle gears

Post by LiftedAWDAstro »

Mark, there are so many different factors it's hard to say what is best. A stripped down shorty cargo 2WD driving in the flat lands of the mid-west would do great with a 3.08 or 3.23's but a fully loaded 2005 AWD is a dog with 3.42's. It all depends on the driving style, type of terrain and ambient outside temperatures.
Current rides:
2013 Toyota Tundra DC 4x4
2008 Dodge Nitro 4x4
2005 Nissan Sentra 1.8S Special Edition

Mileage spreadsheet

Vans owned:
1986 Safari 2.5L 4 speed manual - scrapped
1995 Astro 2WD conversion 4.11 posi, shift kit, DHC rock rails - sold to Skippy
1998 Astro 4x4 D44, D60, NP231, full hydraulic system with 9k# Milemarker winch and snow plow - sold to Lockdoc
2003 Astro AWD all stock - traded for a 3/4 ton truck
2005 AWD, 4.10's - sold to skippy
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Re: your ideas on best all around rear axle gears

Post by doyoulikeithere »

I really liked the 3.08s in my 2wd shrorty, but it had a 5 speed, so not sure how it would be in an automatic...
Same van now has 3.73s, and on the highway I'm always wanting to shift up into 5th , but I'm already there...
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2016 Yamaha XSR900 - Silver.
1990 Astro - AWD - Brown.
1987 Astro - With 5 Speed & 4wd - Silver & Blue.
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1Gary
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Re: your ideas on best all around rear axle gears

Post by 1Gary »

doyoulikeithere wrote:I really liked the 3.08s in my 2wd shrorty, but it had a 5 speed, so not sure how it would be in an automatic...
Same van now has 3.73s, and on the highway I'm always wanting to shift up into 5th , but I'm already there...
Let me look in my crystal ball.........aaaaa there it is.I see a 6 speed Tremic in your future. :yikes:
1979 Malibu drag race only car
1999 Sonoma 4.3 5 speed-Rufus
1989 Astro-Ole Yellar cancelled-still selling off parts
1985 Astro-shop van R.I.P. my friend
1994 Astro LT RWD W4.3 rod knock RIP
1982 Winnebago single rear wheel-Chevy 350 Scraped 1/28/13-broken dreams......


Rochester,NY
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Re: your ideas on best all around rear axle gears

Post by Smiliesafari »

I changed from 3:42's to 3:08's when I built the 12 bolt. It works fine. I really didn't feel much difference. My van is primarily a highway vehicle. I did the change to get a bit more MPG.
Nice chart TL. Thanks.
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6spd_monte
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Re: your ideas on best all around rear axle gears

Post by 6spd_monte »

1Gary wrote:
doyoulikeithere wrote:I really liked the 3.08s in my 2wd shrorty, but it had a 5 speed, so not sure how it would be in an automatic...
Same van now has 3.73s, and on the highway I'm always wanting to shift up into 5th , but I'm already there...
Let me look in my crystal ball.........aaaaa there it is.I see a 6 speed Tremic in your future. :yikes:
+1!
-James

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249,000 miles
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madslammer
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Re: your ideas on best all around rear axle gears

Post by madslammer »

I have an 87 shorty with a 4 inch lift, 235-75-15's and I'm planning on 3.73 with a Gov-Loc... I know I need to get a set of 28 spline axles... The question is, Is the 3.73 too high a gear??? I'm not sure but the one the van has now is a 3.28 I think...
:-k
'97 Astro 2wd, lowered 4" w/Belltech spindles and drop leafs.
'87 Astro 2wd, lifted, pretty close to 4" all around.
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Re: your ideas on best all around rear axle gears

Post by doyoulikeithere »

6spd_monte wrote:
1Gary wrote:
doyoulikeithere wrote:I really liked the 3.08s in my 2wd shrorty, but it had a 5 speed, so not sure how it would be in an automatic...
Same van now has 3.73s, and on the highway I'm always wanting to shift up into 5th , but I'm already there...
Let me look in my crystal ball.........aaaaa there it is.I see a 6 speed Tremic in your future. :yikes:
+1!
Never gonna happen,
Its in a 4x4 1987 Shorty - with 3.73 and a G80 and 235-75-15 tires... (To MadSlammer - sound familiar?)
Do they make that transmission in a 4wd style? :rolleyes:
2021 Yamaha Tenere 700 - Blue.
2016 Yamaha XSR900 - Silver.
1990 Astro - AWD - Brown.
1987 Astro - With 5 Speed & 4wd - Silver & Blue.
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madslammer
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Re: your ideas on best all around rear axle gears

Post by madslammer »

The table above is supposed to be for a "1:1 transmission ratio going about 65mph.", The 700r-4 has a fourth gear that's .70:1 s... That's pretty close to the .73:1 5th gear on the T-5. So i guess it would be better to run 3.42's or fit 31"s under the van... ???
'97 Astro 2wd, lowered 4" w/Belltech spindles and drop leafs.
'87 Astro 2wd, lifted, pretty close to 4" all around.
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Re: your ideas on best all around rear axle gears

Post by doyoulikeithere »

madslammer wrote:The table above is supposed to be for a "1:1 transmission ratio going about 65mph.", The 700r-4 has a fourth gear that's .70:1 s... That's pretty close to the .73:1 5th gear on the T-5. So i guess it would be better to run 3.42's or fit 31"s under the van... ???
I'm quite thankfull for the 3.73 when in the bush starring up a steep gravel hill, or towing a heavy load !
What do you want to use the van for?
mine isnt really intended for a lot of highway use, I have other vans for that.
2021 Yamaha Tenere 700 - Blue.
2016 Yamaha XSR900 - Silver.
1990 Astro - AWD - Brown.
1987 Astro - With 5 Speed & 4wd - Silver & Blue.
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madslammer
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Re: your ideas on best all around rear axle gears

Post by madslammer »

doyoulikeithere wrote:
madslammer wrote:The table above is supposed to be for a "1:1 transmission ratio going about 65mph.", The 700r-4 has a fourth gear that's .70:1 s... That's pretty close to the .73:1 5th gear on the T-5. So i guess it would be better to run 3.42's or fit 31"s under the van... ???
I'm quite thankfull for the 3.73 when in the bush starring up a steep gravel hill, or towing a heavy load !
What do you want to use the van for?
mine isnt really intended for a lot of highway use, I have other vans for that.
I don't really use it off road, but rather I need it to perform well all around... It's mostly highway used, with the occasional dirt road and slightly muddy situations...
Thanks...
'97 Astro 2wd, lowered 4" w/Belltech spindles and drop leafs.
'87 Astro 2wd, lifted, pretty close to 4" all around.
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