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3.42-3.73 rear end change.

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Old Mar 15, 2014 | 11:58 PM
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Default 3.42-3.73 rear end change.

I have recently bought 3.73 gears for my 99 silverado 4.8, im debaiting throwing them in, Would i feel better pull at lower rpm? Im really struggling in the 1000-3200 rpm range.
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Old Mar 16, 2014 | 12:30 AM
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I swapped from 3.73's to a 4.10 once to be honest it was not worth the trouble, it felt a "little" better from red light to red light on the expressway it felt like i had less power on the top side, lost 1.5 mpg witch hurt I was driving about 30k per year at the time

a stall might be a better option just my $0.02
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Old Mar 16, 2014 | 01:21 AM
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Well it depends on what you are going for and what your setup is. ex when i had me rcsb with 24's i went with 4.10's to give a stock feel of it with a 3.73 and it did for the most part. now i was surprised on intestate it did turn kinda hard , but is still managed 18 mpg untuned. I have always been told 373 are best all round ,but i thinks its all in the application. use the gear calculators to figure rpm vs tire size as to where you would like to be.
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Old Mar 16, 2014 | 10:15 AM
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depends on the tire size. cruising on the interstate at 70-80 its going to raise your rpms up by about 200 or so. for the $500 or so its going to take for you to buy them and get them installed you would of been better off with a stall or higher ratio.
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Old Mar 16, 2014 | 10:59 AM
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I went from 3.42 to 3.73 when I blew my stock unit up because the rear end I got to replace mine had 3.73s in it. It does feel a little better but if I was buying gears I would have got 4.10s probably. I think you would be happier with about a 3000rpm stall really.
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Old Mar 16, 2014 | 11:26 AM
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I would do 4.10s at least if you want to feel a difference.
Also, tire size info would help.
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Old Mar 16, 2014 | 01:48 PM
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Originally Posted by Ricksilvy
I would do 4.10s at least if you want to feel a difference.
Also, tire size info would help.
I have a 4.10 in my 2004 6.0/4l80e hate it on the expressway 75/80mph its @ 2800 to 3000rpm's plus my truck fall on its face around 85mph.......running a 29.5 tire though might be ok for a 4wd with taller tires
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Old Mar 16, 2014 | 03:46 PM
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i understand what your saying but it looks to me your spinning 1-300 rpms higher then my calculator says. unless you have a 4l80e with a higher overdrive. 70-80 in the calculator says 2200-2600rpms.
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Old Mar 16, 2014 | 03:50 PM
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I'm running 4.10s, 2500 stall and 30" tires. 2004 RCSB 2wd 4.8L Hughes street/strip trans. I went from 3.42s and stock. I would NOT change back for anything. Yes it revs a little more on the freeway but damn it's a smile maker.
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Old Mar 16, 2014 | 04:07 PM
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Originally Posted by bobfig
i understand what your saying but it looks to me your spinning 1-300 rpms higher then my calculator says. unless you have a 4l80e with a higher overdrive. 70-80 in the calculator says 2200-2600rpms.
yeah if i was running those RPM's on the highway I'd be happy, I'm thinking of dropping to 3.42 I think since its going to be turbo's I might be ok




Originally Posted by Lilbro
I'm running 4.10s, 2500 stall and 30" tires. 2004 RCSB 2wd 4.8L Hughes street/strip trans. I went from 3.42s and stock. I would NOT change back for anything. Yes it revs a little more on the freeway but damn it's a smile maker.
what rpm's are you @ when doing 75mph?
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