02-29-2012, 02:17 AM | #1 |
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3.42-3.73 gear swap?
I have an 02 silverado(2wd), that is running a 3.42 gear. My parts truck is sportin a 3.73 diff, & I know it will "bust" the mileage a tad going 3.73, but be nice behind that 4.8, pullin a stock car trailer My ? is how much tune do I need to play, to make it work properly? crazyL
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69 longhorn,4" chop,3/5 drop, 1/2 ton suspension/disc brakes,1 1/2" body drop,steel tilt clip, 5.3/Edelbrock rpm intake/600 carb, Hooker streetrod shorties,2 1/2" exhaust/ H pipe/50's Flows , 6 spd Richmond trans,12 bolt/ 3.40 gears.... |
02-29-2012, 01:29 PM | #2 |
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Re: 3.42-3.73 gear swap?
Just put them in and go, no need to wory about tuning the motor
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02-29-2012, 04:31 PM | #3 |
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Re: 3.42-3.73 gear swap?
Only thing the PCM would need to be programed for is to correct the speedo.
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02-29-2012, 04:34 PM | #4 |
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Re: 3.42-3.73 gear swap?
Thanks guys crazyL
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69 longhorn,4" chop,3/5 drop, 1/2 ton suspension/disc brakes,1 1/2" body drop,steel tilt clip, 5.3/Edelbrock rpm intake/600 carb, Hooker streetrod shorties,2 1/2" exhaust/ H pipe/50's Flows , 6 spd Richmond trans,12 bolt/ 3.40 gears.... |
03-05-2012, 08:03 PM | #5 |
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Re: 3.42-3.73 gear swap?
You can do without, but it should really be tuned to fix the shift points also. They will be different.
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2010 Basalt Black Porsche Cayenne GTS - Daily driver 1991 2500 Suburban, Black - 454/80E tow monster, soon to go under the knife... Again. 1979 16' Action Marine/"Johnny Cash" Merc Bridgeport Champ Motor - Metalflake Maniac |
03-05-2012, 10:24 PM | #6 |
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Re: 3.42-3.73 gear swap?
I had wondered about the shift points.....the old school stuff , always messed with the shift points ,running lower gears. Tiss my 1st rodeo on the 3rd gen , I love my 02 silverado(4.8), & that is what the diff swap is about. I have a 5.3 to roll in my old 69 longhorn/backed with a Richmond 6 spd box, & 3.42 gears. She will be goin "rock stock", with a little tune.....maybe add the cam upgrade& valve springs, next season. The old 383 has showed me all she has.....but fuel mileage was not in the picture. crazyL
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69 longhorn,4" chop,3/5 drop, 1/2 ton suspension/disc brakes,1 1/2" body drop,steel tilt clip, 5.3/Edelbrock rpm intake/600 carb, Hooker streetrod shorties,2 1/2" exhaust/ H pipe/50's Flows , 6 spd Richmond trans,12 bolt/ 3.40 gears.... |
03-06-2012, 01:25 AM | #7 |
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Re: 3.42-3.73 gear swap?
Its the same theory as changing speedo gears & calibrating a governor in a older ride, Just its all in the "Flash Memory" in the PCM.
3.42:1 to 3.73:1 isnt a huge change. It would run fine....But better with a good tune. |
03-06-2012, 01:37 AM | #8 |
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Re: 3.42-3.73 gear swap?
Any betts on mileage difference? My thoughts are probably about nothing in town....but I may need to slow down a tick on the hyway?
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69 longhorn,4" chop,3/5 drop, 1/2 ton suspension/disc brakes,1 1/2" body drop,steel tilt clip, 5.3/Edelbrock rpm intake/600 carb, Hooker streetrod shorties,2 1/2" exhaust/ H pipe/50's Flows , 6 spd Richmond trans,12 bolt/ 3.40 gears.... |
03-06-2012, 01:46 AM | #9 |
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Re: 3.42-3.73 gear swap?
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03-06-2012, 02:25 AM | #10 |
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Re: 3.42-3.73 gear swap?
235/75/16....they are a little shorter than what was on the 4wd parts truck. crazyL
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69 longhorn,4" chop,3/5 drop, 1/2 ton suspension/disc brakes,1 1/2" body drop,steel tilt clip, 5.3/Edelbrock rpm intake/600 carb, Hooker streetrod shorties,2 1/2" exhaust/ H pipe/50's Flows , 6 spd Richmond trans,12 bolt/ 3.40 gears.... |
03-06-2012, 11:21 AM | #11 | |
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Re: 3.42-3.73 gear swap?
Quote:
For the size tires that are generally considered truck tires these days, 3.73s are the way to go.
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2010 Basalt Black Porsche Cayenne GTS - Daily driver 1991 2500 Suburban, Black - 454/80E tow monster, soon to go under the knife... Again. 1979 16' Action Marine/"Johnny Cash" Merc Bridgeport Champ Motor - Metalflake Maniac |
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03-06-2012, 04:19 PM | #12 |
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Re: 3.42-3.73 gear swap?
we did a 3.73-4.10 swap in a 2000 Siliverado 5.3L 1/2 ton 2wd years ago without any reprogramming and the speedo was only about 1-2 mph off. no real effect on shift points either. It ran great. so we just left it alone after the install.
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03-06-2012, 09:04 PM | #13 |
Fabricate till you "puke"
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Re: 3.42-3.73 gear swap?
Thanks again, to all for the info....it sounds like I will bolt in & play. I may go with the tune later, but this one is my DD. Hotrods 1st! I am working on the 5.3 into my old 69.....dam, this old man has refound some sore muscles, tearing the parts truck down if it jacks with me too hard, I just lite the "smoke wrench" tho...thanks again,crazyL
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69 longhorn,4" chop,3/5 drop, 1/2 ton suspension/disc brakes,1 1/2" body drop,steel tilt clip, 5.3/Edelbrock rpm intake/600 carb, Hooker streetrod shorties,2 1/2" exhaust/ H pipe/50's Flows , 6 spd Richmond trans,12 bolt/ 3.40 gears.... |
03-06-2012, 11:40 PM | #14 |
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Re: 3.42-3.73 gear swap?
Hi, I have a 2008 4.3 2wd reg cab with 3.23's but I'm planning on going from the stock 245 to 285 tires so I want to get 3.73 or 4.10 gears but which one? And what are the pros and cons? I wouldn't mind the better acceleration either!
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