1500hd Thinking About Regearing To 456 Or 488?

Mayfieldsa1 · February 23, 2011

Ok, I have a 06 1500HD with a 6" lift and 35" tires and 373 rearend. I had my tune done by black bear performance which I love. I was getting about 9mpg before the tune and I average about 12mpg now, and the best Ive gotten is 13.2 mpg. Which Im very happy with considering the truck I have.

I have issues with holding it in OD, most of it was taking care after the tune, but Im looking for a little more for take off. it's not terrible, but its not that great either, and I would like to be able to hold OD longer than what it is now. I called 4 wheel parts in nashville, and Im looking about $1700 to regear both front and rear, I don't think thats a bad price, I would rather pay that kind of money to have it done right and have a peace of mind about it. Right now @ 60, I'm turning around 1800rpm. I know that regearing would increase my rpm but I was wondering by how much? My theory is that, I think my truck would be more efficent because it want be working as hard to get up to speed and maintain it, and I might see an increase in fuel milage? I guess im trying to bring it back close to stock, I don't know what that would be cause I bought the truck already lifted with the tires. I heard that the 4l80e is doggy off the start factory, because of the first gear ratio, is this true?

I have searched this forum for answers, but they all seem to relate to the 1500's with the 4l60e. i guess I'm asking for answers from the ones that have done this, did you go with 456, or did you go a little lower with 488? Where you happy with your decision, did you regret it? Did it bring back performance that you lost from large tires and a lift? Did your gas milage increase or decrease? I'm sorry for the long drawed out page, but I would really like some answers before I spend that kind of money for a gear change. Thanks for your time!

Mike G · February 23, 2011

I don't think you need to go any bigger than the 456's, but the guys at 4WP should be able to calc what you need to get back to stock equivalent.

--Mike

Diesail · February 23, 2011

I'm not sure you need any more than 4.11s. Here is a Gear Calculator for you

Mayfieldsa1 · February 23, 2011

I don't think you need to go any bigger than the 456's, but the guys at 4WP should be able to calc what you need to get back to stock equivalent.
--Mike

Yes, they did calculate it out for me and recomended the 456's to get back close to stock. I was just wondering if I should go a little bit lower to help with the low end grunt. I know there is some on here that has an identical setup, I was just curious how they liked it. Thanks!

beave84 · February 23, 2011

I don't think you need to go any bigger than the 456's, but the guys at 4WP should be able to calc what you need to get back to stock equivalent.
--Mike

Yes, they did calculate it out for me and recomended the 456's to get back close to stock. I was just wondering if I should go a little bit lower to help with the low end grunt. I know there is some on here that has an identical setup, I was just curious how they liked it. Thanks!

4.11's got me real close to stock and MPG but mileage suffers from rolling resistance of the 35 12.50's they are alot heavier then stock tire's

Silverado4x4 · February 23, 2011

I don't think you need to go any bigger than the 456's, but the guys at 4WP should be able to calc what you need to get back to stock equivalent.
--Mike

Yes, they did calculate it out for me and recomended the 456's to get back close to stock. I was just wondering if I should go a little bit lower to help with the low end grunt. I know there is some on here that has an identical setup, I was just curious how they liked it. Thanks!

4.11's got me real close to stock and MPG but mileage suffers from rolling resistance of the 35 12.50's they are alot heavier then stock tire's

Your right, your biggest drop in MPG is the tires and the lift as your trapping more wind load under the truck plus if your figureing it up buy hand thats going to be off now due to the larger tires as the truck is going faster then the speedo is saying by about 3-4 MPH. Gears are not going to bring back your normal MPG.

Mayfieldsa1 · February 24, 2011

I'm not sure you need any more than 4.11s. Here is a Gear Calculator for you

according to the calculation I will need a 4.35, so yes a 4.11 would get me closer to stock, so for more grunt off the line 4.56 should be plenty.

Anyone on here has went from 3.73 to 4.56 gears?

Stevens03 · February 24, 2011

Thats a common gear swap. I wouldn't do any less than 4:56's though and would even consider 4.88's. Because of the weight of the tires to help. You might find your mileage better with the 4.88's than you would with the 4.56's unless your doing mostly highway.

If you want more grunt, then the 4.88's would be what I'd get.

Diesail · February 24, 2011

Will all the gears fit the same carrier?

hy_69 · February 24, 2011

i currently have 4.56 gears with 35x12.5 tires in my 99 silverado 4x4 ext cab.... someone told me it was a very high gear! that i could be running 37's easily maybe 39's with those gears.... i couldnt be happier with the gear/tire combo! in highway you see slightly higher rpm's than with stock gears/tires, nothing to worry about, but the trucks just feels with so much power! you wont feel like you have bigger tires! and it does help with city mpg! that is if you can keep your foot out of the gas! if you do lot of highway then 4.11 shlould do the job! you'll still have plenty of power and wont mess up that much with highway mph...

Mayfieldsa1 · February 25, 2011

i currently have 4.56 gears with 35x12.5 tires in my 99 silverado 4x4 ext cab.... someone told me it was a very high gear! that i could be running 37's easily maybe 39's with those gears.... i couldnt be happier with the gear/tire combo! in highway you see slightly higher rpm's than with stock gears/tires, nothing to worry about, but the trucks just feels with so much power! you wont feel like you have bigger tires! and it does help with city mpg! that is if you can keep your foot out of the gas! if you do lot of highway then 4.11 shlould do the job! you'll still have plenty of power and wont mess up that much with highway mph...

Thats what I'm hoping for with the 4.56 gears. I'm still torn between the 4.56 and the 4.88 I don't drive a lot of highway but I still not sure because the 4l80e has a taller first gear. I'm going to regear, I just don't want to regret not getting one or the other! Factory is a 30" tire and now I have 35". With the online calculator it shows I'm between a 4.10 and 4.56. i'm thinking that if i go with the 4.56 it would be close to running the factory tires and a 4.10 rearend?

hy_69 · February 25, 2011

i currently have 4.56 gears with 35x12.5 tires in my 99 silverado 4x4 ext cab.... someone told me it was a very high gear! that i could be running 37's easily maybe 39's with those gears.... i couldnt be happier with the gear/tire combo! in highway you see slightly higher rpm's than with stock gears/tires, nothing to worry about, but the trucks just feels with so much power! you wont feel like you have bigger tires! and it does help with city mpg! that is if you can keep your foot out of the gas! if you do lot of highway then 4.11 shlould do the job! you'll still have plenty of power and wont mess up that much with highway mph...

Thats what I'm hoping for with the 4.56 gears. I'm still torn between the 4.56 and the 4.88 I don't drive a lot of highway but I still not sure because the 4l80e has a taller first gear. I'm going to regear, I just don't want to regret not getting one or the other! Factory is a 30" tire and now I have 35". With the online calculator it shows I'm between a 4.10 and 4.56. i'm thinking that if i go with the 4.56 it would be close to running the factory tires and a 4.10 rearend?

i dont know how different are hd gears from the non hd trucks... but in my case! i have a 1500 non hd! that it also came with 30 tires and now im running 35... 4.56 was the best choice! has lots of power! feels like a different truck from a stock one.... i think 4.88 for me! wouldnt be a good choide! it will mess up too much with highway... my truck right now says i'm doing 75mph when my gps actually says i'm doing like 67-68mph like at 2000-2200 rpm... soo imagine what the numbres would be if i had 4.88... i dont think i would enjoy that very much and as for off-roading it is great! never felt the need for different gears... but i do light off roading! climbing here and there not rock crawling or something like that... so it all depends on what are you using your truck for... if gears work the same way in the hd than in the non hd! i would 100% recommend you to go with the 4.56! but not sure if it works that way! just sharing my thoughts with my truck running those gears/tires... is the best in power you feel so much torque without messing up that much the speedo and highway dirveability

Stevens03 · February 25, 2011

Refer to the chart for help

http://www.4lo.com/calc/geartable.htm

Mayfieldsa1 · February 25, 2011

Refer to the chart for help

http://www.4lo.com/calc/geartable.htm

Thanks for the chart! I guess I will go with the 4.56. I think I will call them today and set up a appointment. Has anyone had trouble with the ABS light after changing gears? Thanks for all the replys. I will post on here what it's like after I get it done.

hy_69 · February 25, 2011

Refer to the chart for help

http://www.4lo.com/calc/geartable.htm

Thanks for the chart! I guess I will go with the 4.56. I think I will call them today and set up a appointment. Has anyone had trouble with the ABS light after changing gears? Thanks for all the replys. I will post on here what it's like after I get it done.

yeS!! i have!! be prepared to deal with having abs/p.brake on all day but i'm planning on getting blackbear so that will be fixed... but every morning when i start my truck abs/p.brake lights are off... and after driving 2-6 miles it will pop up! there is no way to avoid this i think! because the readings the computer is receiving are all messed up! but it does not affect your ride! but i hate seeing lights on in my cluster! when i save up enough money for blackbear ill get rid of the abs/p.brake lights that i have because of the gears/tires and the SES light i have because i removed my cats since installing plugs non foulers in the o2 sensors didnt work for me