Re Gear Or Not?

Silverado2009 · June 15, 2010

Im getting so many mixed signals about regearing a lifted truck. I hear it saves gas, tranny life etc etc. I know a guy with an 09' Silvo ext cab, 4.3 ltr 2wd with the RC 7.5" lift and 35x12.5 tires and did not regear and has no power loss or anything. I want to put that RC lift on mine with same size shoes. I have the 4.8ltr V8 4x4 ext cab, it currently has 3.42 gears in it. I have been told by some people that the Chevys have pretty good gears and its not needed. I have no intentions on doing serious off roading just the occasional backwoods camping trip, it will be a street ride mostly but i do want the true suspension lift?

Whats the best way?

Stevens03 · June 15, 2010

If your only going to run 33" tires, your 3.42's will feel a little sluggish but do just fine for you. If you run 35" tires your gonna feel the pain. Who ever told you the 4.3 lost no power running 35" tires was lying to you. He had no power to begin with so the loss didn't feel like much imo.

Since you have the 4-speed, the 3.42's are going to be WEAK for 35" tires and you should Regear to 4.10s at a min. and 4.56's would be best to keep your truck within the power band it came stock with. The 4.8 is a good motor but lacks on torque and being under geared with 3.42's and 35" tires, your mileage will be horrible, the extra stress on your transmission will/could cause problems shortly down the road. If 35's are what you want to run, then do it right and you'll be happier.

Do that and you'll be fine.

Good luck

Silverado2009 · June 15, 2010

If your only going to run 33" tires, your 3.42's will feel a little sluggish but do just fine for you. If you run 35" tires your gonna feel the pain. Who ever told you the 4.3 lost no power running 35" tires was lying to you. He had no power to begin with so the loss didn't feel like much imo.

Since you have the 4-speed, the 3.42's are going to be WEAK for 35" tires and you should Regear to 4.10s at a min. and 4.56's would be best to keep your truck within the power band it came stock with. The 4.8 is a good motor but lacks on torque and being under geared with 3.42's and 35" tires, your mileage will be horrible, the extra stress on your transmission will/could cause problems shortly down the road. If 35's are what you want to run, then do it right and you'll be happier.

Do that and you'll be fine.

Good luck

Thats the best answer I have gotten yet.I agree, I just wasnt sure and didnt want to waste money if I didnt need to. Thanks for the info.

BrockwayMT · June 15, 2010

Mathwise a ~3.90 with 35s is the same as 3.42 with ~31 stock tires. I'd tend to go with 4.11 although the 4.56 may not hurt since the highway mpg won't be anything special with 35s.

hockeypro1411 · June 15, 2010

I have the 6.0 with 4.10's sitting on 35's. I can tell you that if I had 35's on a 4.8, there's no doubt that I'd be running 4.56's or maybe even 4.88's.

lbkthree · June 15, 2010

If your only going to run 33" tires, your 3.42's will feel a little sluggish but do just fine for you. If you run 35" tires your gonna feel the pain. Who ever told you the 4.3 lost no power running 35" tires was lying to you. He had no power to begin with so the loss didn't feel like much imo.

Since you have the 4-speed, the 3.42's are going to be WEAK for 35" tires and you should Regear to 4.10s at a min. and 4.56's would be best to keep your truck within the power band it came stock with. The 4.8 is a good motor but lacks on torque and being under geared with 3.42's and 35" tires, your mileage will be horrible, the extra stress on your transmission will/could cause problems shortly down the road. If 35's are what you want to run, then do it right and you'll be happier.

Do that and you'll be fine.

Good luck

What he said ^^

jro909 · June 15, 2010

who told you that 4.3 lost no power needs to stop smoking crystal meth, i'd regear...

Matt_ · June 15, 2010

Mathwise a ~3.90 with 35s is the same as 3.42 with ~31 stock tires. I'd tend to go with 4.11 although the 4.56 may not hurt since the highway mpg won't be anything special with 35s.

That math doesn't take into account weight and rolling resistance.

Not to mention 3.42s are not an ideal "towing" gear to begin with... having 35s on the truck is like towing a trailer on a constant basis; so using 3.42s as your "base" gear is not a good idea.

4.56s or 4.88s are the best for 35s (on the 1500s with the 4L60E). With the 4.8, i definitely would go with 4.88s.

FYI, i had stock 4.10s in my 5.3L truck and it was a dog when i put 35s on it. I got better HIGHWAY mpg (70 miles DD) when i swapped my 4.10s for 4.88s. Just some food for thought....

hockeypro1411 · June 15, 2010

Mathwise a ~3.90 with 35s is the same as 3.42 with ~31 stock tires. I'd tend to go with 4.11 although the 4.56 may not hurt since the highway mpg won't be anything special with 35s.

That math doesn't take into account weight and rolling resistance.

Not to mention 3.42s are not an ideal "towing" gear to begin with... having 35s on the truck is like towing a trailer on a constant basis; so using 3.42s as your "base" gear is not a good idea.

4.56s or 4.88s are the best for 35s (on the 1500s with the 4L60E). With the 4.8, i definitely would go with 4.88s.

FYI, i had stock 4.10s in my 5.3L truck and it was a dog when i put 35s on it. I got better HIGHWAY mpg (70 miles DD) when i swapped my 4.10s for 4.88s. Just some food for thought....

Random question... Do you know the trans. gearing differences between the 4l60 and 4l80? I know the 4l80 has a lower first gear for getting everything rollin', but I don't know the specific numbers.

Matt_ · June 15, 2010

actually the 4L60 has a lower 1 to 2 ratio than the 4L80.... so if you swap your 60 for an 80 you'll likely lose some performance (edit: see you have a HD already.. so obviously the swap statement doesnt apply to you.)

4l60e

1st 3.06

2nd 1.75

3rd 1.00

4th .70

4l80e

1st 2.48

2nd 1.48

3rd 1.00

4th .75