Gear Swap Help
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Fleet Mechanic
Joined: Sep 2002
Posts: 1,769
Likes: 7
From: Gretna ,LA.
SD Gear Swap Help
I have done searches, but come up with conflicting views.I have 3.73,s now, and if i want to change to 4.56 w/stock tires, do i have to do anything with the computer?I have heard that the speedo will be alright because it reads off of ring gear.I dont think the 4.56,s will be to extreme with the OD gearing and all.Maybe its just me being to extreme,but i think they would compliment my mods on my truck.Suggestions? Its just that i have been reading that there is not much noticable difference in 3.73-4.30,s.The 3.73 gear is to high for me.Could you imagine the towing capability then?
Last edited by V10KLZZ71S; Oct 31, 2003 at 06:33 AM.
Post Fiend
Joined: Jan 2002
Posts: 5,859
Likes: 7
From: USA
What your doing ,depends on what you want to do with that truck !
Towing heavey loads for short distance ,because your going to lose fuel mileage .
yes ,nothing needs to be done to the computer unless you change the tire size,with the ring gear size.
The way you should look at it is what rpm do I want to be turning at highway speeds ????(when towing)
Again what do you want to do with the truck???
4.56 with stock tires is not the way to go
3.73 gear is the best fuel milage gear out there for the v-10 auto .
4.30 would be my choice if I towed alot !
Just my $.02
Rich
Towing heavey loads for short distance ,because your going to lose fuel mileage .
yes ,nothing needs to be done to the computer unless you change the tire size,with the ring gear size.
The way you should look at it is what rpm do I want to be turning at highway speeds ????(when towing)
Again what do you want to do with the truck???
4.56 with stock tires is not the way to go
3.73 gear is the best fuel milage gear out there for the v-10 auto .
4.30 would be my choice if I towed alot !
Just my $.02
Rich
Senior User
Joined: Sep 2003
Posts: 275
Likes: 0
From: Anderson, SC
What are you towing with this truck? I don't know who said there's not a noticeable difference between 3.73 and 4.30, but I don't believe it. I can tell a noticeable difference between my 3.73 and 4.10s that friends have. I think 4.56 would be a mistake, even 4.30 if you drive on the highway. For someone who tows 50% of the time, I say the 4.10 is the best bet. I tow about 20% of the time, and run the Interstate alot, so I have no complaints at all with the 3.73, even running 305 tires. Everyone has a different opinion on this.
Laughing Gas
Joined: Oct 2003
Posts: 767
Likes: 132
From: Lynden, WA
Having towed for years with every possible gearing combo, I suggest you reconsider 4.56's. With an auto trans & 4.56 gears, RPM's are going to be about 21-2300 @ 60mph with stock tires (32"). I've towed for years with 4.56 and 33"-35" tires with no problems but would think that 4.10/4.30's with stock tires would be a better bet. My new truck has the V10 4.30 combo and should be great with 33" tires. Problem with 4.56 and autos are that you're geared low enough ahd have enough power to pull a pretty good load in OD which is not what you want to be doing for good trans life. Dropping back into 3rd and you're turning some pretty good RPM's. Seems there is the likelihood of keeping it in OD as long as it's pulling OK. I would suggest 4.10 with stock tires and 4.30 with 33" and 4.56's with 35" tires. But much depends on what you're towing and where you're towing it. I tow the west coast from Mexico to Alaska and the BC mountains have some hard pulls.
New User
Joined: Dec 1999
Posts: 17
Likes: 0
From: La Mesa USA
70 mph with stock tires and 3.73 gears is around 2000 rpm. the switch to 4.30 would raise the 70 mph rpm up to around 2300. There is a little more power available at 2300 rpm, when towing a load the truck will feel more responsive
