I need advice on gears.

jaelmore12 · March 9, 2016

If anyone may be able to assist me it would be greatly appreciated. I am looking to re-gear my truck from factory to something else. I have read from multiple forums, good and bad things about some of these gears I've been in comparison between. The 4.56 and the 4.10. Most of my driving is done city, but I also travel from South Texas to West and Central Texas. Not very often but I do. I currently have a 5 inch suspension lift kit and 33" tires. I want to move up to 35" tires once these bald out. I don't rough up the truck, don't off-road or do anything like that. She is my daily driver. Any advice on which gear kit to purchase would be helpful and if so:

1. What do I need to purchase?

a) Is it just the ring and pinion, or will it have to be the entire kit.

2. Which gear ratio is best for both city and highway driving.?

a) As said before I don't rough it up but, occasionally I pull a single axle trailer with a motorcycle and quad.

3. How do I go about timing the gears to change properly?

Thanks a lot for any help I may receive.

God Bless America.

bgbdwlf2500 · March 11, 2016

First question is what gears do you have now? If you have 3.73s id say leave them alone, 3.43 or 3.08 a change will help. Only thing you need to remember is the higher the number the "lower" the ratio is, meaning you will pull and accelerate quicker than a truck with a lower number ratio but on the highway your engine will turn more rpms which hurts your mpgs. For example, unfortunately i bought my truck not knowing it had the 3.08 ratio. Acceleration from a stop as well as accelerating after slowing down, suck in my opinion but that being said 70 mph on the highway = 1500 rpm. 3.73 gears typically are 2000 to 2100 rpm at 70. Key is to find the happy medium. 4.11 is a factory ratio typically on HD trucks needing the tow capacity. With 4.56 gears you could pull a house down, but youre not going to pass a gas station. hope that helps

all you need to do to complete the swap is buy the ring and pinion and either install the gears or have them installed. they have to be meshed correctly or they will fail. i would love to swap mine out but i dont want to take the chance on them not being meshed and fail so i would have to get them installed. the gears i can get for about 250 but was quoted nearly 1,000 to have them installed. the trans will shift at the same points, changing gears doesnt have anything to do with it. also, if youre a 4x4 remember you have to do both sets

jaelmore12 · March 16, 2016

hey bgbdwlf2500 I really do appreciate the help. I will contact the dealership and have them run my vin so they can tell me which gear ratio I currently have. and I agree my acceleration is a little slower now that I have the bigger tires. i run around 2200-2400 rpm at 75-80mph. but again thanks for the help.

jaelmore12 · March 16, 2016

First question is what gears do you have now? If you have 3.73s id say leave them alone, 3.43 or 3.08 a change will help. Only thing you need to remember is the higher the number the "lower" the ratio is, meaning you will pull and accelerate quicker than a truck with a lower number ratio but on the highway your engine will turn more rpms which hurts your mpgs. For example, unfortunately i bought my truck not knowing it had the 3.08 ratio. Acceleration from a stop as well as accelerating after slowing down, suck in my opinion but that being said 70 mph on the highway = 1500 rpm. 3.73 gears typically are 2000 to 2100 rpm at 70. Key is to find the happy medium. 4.11 is a factory ratio typically on HD trucks needing the tow capacity. With 4.56 gears you could pull a house down, but youre not going to pass a gas station. hope that helps

all you need to do to complete the swap is buy the ring and pinion and either install the gears or have them installed. they have to be meshed correctly or they will fail. i would love to swap mine out but i dont want to take the chance on them not being meshed and fail so i would have to get them installed. the gears i can get for about 250 but was quoted nearly 1,000 to have them installed. the trans will shift at the same points, changing gears doesnt have anything to do with it. also, if youre a 4x4 remember you have to do both sets

hey bgbdwlf2500 I really do appreciate the help. I will contact the dealership and have them run my vin so they can tell me which gear ratio I currently have. and I agree my acceleration is a little slower now that I have the bigger tires. i run around 2200-2400 rpm at 75-80mph. but again thanks for the help.

bgbdwlf2500 · March 16, 2016

hey bgbdwlf2500 I really do appreciate the help. I will contact the dealership and have them run my vin so they can tell me which gear ratio I currently have. and I agree my acceleration is a little slower now that I have the bigger tires. i run around 2200-2400 rpm at 75-80mph. but again thanks for the help.

look in your glove box for the square sticker with all the 3 character number/letter combos. my code is gu4 which translates to the 3.08 ratio. obviously theres a few others, most do start with gu so if you see that code just google search gm rpo code ???

jaelmore12 · March 16, 2016

look in your glove box for the square sticker with all the 3 character number/letter combos. my code is gu4 which translates to the 3.08 ratio. obviously theres a few others, most do start with gu so if you see that code just google search gm rpo code ???

jaelmore12 · March 16, 2016

I appreciate the help. I'm running gh5 3.23 right now. I think i will upgrade but not too much, up to the gt4 3.73. Just enough to make a difference in the acceleration dept. But still be easy on my mpg on the highway.

bgbdwlf2500 · March 17, 2016

I appreciate the help. I'm running gh5 3.23 right now. I think i will upgrade but not too much, up to the gt4 3.73. Just enough to make a difference in the acceleration dept. But still be easy on my mpg on the highway.

Looks like you are correct that you have the 3.23 so going up will have a big impact with bigger tires and towing. The 3.73 is a good all around ratio and will increase your towing capacity also. as i said, if you are a 4x4 you MUST change out front and rear before you engage 4x4

jaelmore12 · March 20, 2016

Looks like you are correct that you have the 3.23 so going up will have a big impact with bigger tires and towing. The 3.73 is a good all around ratio and will increase your towing capacity also. as i said, if you are a 4x4 you MUST change out front and rear before you engage 4x4

thank you for the advice and again thanks for the help. I will definitely have this done soon.

bgbdwlf2500 · March 20, 2016

thank you for the advice and again thanks for the help. I will definitely have this done soon.

no problem, let us know what you think when you have it done. as I said my truck has the 3.08 and I'm used to 3.42 and 3.73 so I hate the feel from a stop and from accelerating from a slow down

jaelmore12 · March 21, 2016

no problem, let us know what you think when you have it done. as I said my truck has the 3.08 and I'm used to 3.42 and 3.73 so I hate the feel from a stop and from accelerating from a slow down

yeah its a bit of a drag to accelerate and as I said earlier I travel a little so the acceleration to pass another car is a bit slow as well. but I will definitely update after I have the new gears installed.

Big Whiskey · March 23, 2016

If you're going to run 35" tires in the future, then 3:73 will be a waste of money. Go with the 4:10....or maybe even 4:56. What engine & transmission do you have?