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Going to 35's plus lift... should i regear??

CJMOFFAT

CJMOFFAT

Full Member
Joined
May 12, 2012
Messages
49
Location
Tennessee
I just joined the forum and if this isn't the right place please let me know  :E: but i have a 6 inch fabtech lift on its way with 22 inch xd monster rims and 35 inch nitto trail grapplers... i was wondering if i need to regear or not and if so what should i regear too. Everywhere i looked gives me mixed answer saying 4:10 or 4:86 but i would like a good solid answer from someone with a similar set up... Also the most i would be pulling is two jet skis on an aluminum trailer thanks  :D

PS. I'm turning 17 tomorrow (May 14) so id like to know soon before i blow any money i get on something useless haha.
 
Yes, going to 35s you should definitely regear.  And yes, the 4.10 to 4.86 is the proper range for 35s.  You trade off will be fuel economy vs towing power.  Being that your probably not going to be towing that much weight, you would probably be fine with the 4.10.  Only if you plan on towing allot should you move up to the bigger gears. 

And Dam!  17 with a 2007 Av with a 6" Fabtech lift!  Your parents want another son??
 
alright thanks for the info, do i need to worry about regearing right away or can it wait? :E:

hahahaha nah i annoy them enough already you can try though if you'd like  :kidding:
 
Personal opinion, you should go with 4.56's for 35" tires. You'll have more power and get better gas mileage than with 4.10's.  I didn't look at your profile but if you're 4X4 you can figure at least $2000 for the swap. I you've got 3.73's now, there's no way in he!! I would try to run 35's. If you can't afford the gear swap, I'd wait until you can do it all.
 
Well everythings on its way here and i already have it set to install and theres no way i can spring another 2grand into it cause it is 4x4... Who would lift a 2wd (n)... Yall think if i go really easy on the gas ill be ok? Ive known people to run 37s and not regear and be ok it was a duramax or powerstroke and i know theres a huge difference but still haha.... I cant hold it off long enough to get new gears.... Is there a way to find out what gears i have? I really hope thats not a stupid question haha
 
Look in the glovebox. It will most likely be either GT4 or GT5; GT5 is 4.10 and GT4 is 3.73. If you have an 05 you could possibly have 3.42 gears (GU6 code) and if you do, you absolutely should not try to run 35's. You will have absolutely zero power and absolutely horrible gas mileage.

If you haven't budgeted for it yet, you also need to plan on purchasing a Predator programmer, Hypertech programmer, or other similar programmer to allow you to correct the speedometer for the larger tires. You should also be able to use it to correct for the new gears if and/or when you get them.

As far as someone lifting a 2X, you'd be surprised how many people do it. I agree with you as far as it being pretty silly. But then there are probably quite a few people who think I was pretty silly for trying to make a 6000 lb. truck that will outrun quite a few pony cars.
 
Sorry, I checked your profile and see you have an 07 LTZ. Here are the possible codes:

GT4      Rear axle, 3.73 ratio
GT5      Rear axle, 4.10 ratio
GU5      Rear axle, 3.23 ratio
GU6      Rear axle, 3.42 ratio

My truck's an 02 so I haven't kept up on all of the model-year-specific changes; I believe the tranny was still a 4-speed in 07 and went to a 6-speed in 08. If you have a 6-speed tranny, you could probably get by OK with 4.10's. 4.56's would still give you better acceleration and gas mileage.
 
MyBigToy said:
Sorry, I checked your profile and see you have an 07 LTZ. Here are the possible codes:

GT4       Rear axle, 3.73 ratio
GT5       Rear axle, 4.10 ratio
GU5      Rear axle, 3.23 ratio
GU6      Rear axle, 3.42 ratio

My truck's an 02 so I haven't kept up on all of the model-year-specific changes; I believe the tranny was still a 4-speed in 07 and went to a 6-speed in 08. If you have a 6-speed tranny, you could probably get by OK with 4.10's. 4.56's would still give you better acceleration and gas mileage.
Click to expand...

09 was the first year for the 6-speed so he has the 4-speed.
also only 2 choices for gear in 07-08.
GT4       Rear axle, 3.73 ratio
GT5       Rear axle, 4.10 ratio
The other 2 were with the 6-speed

Edit it was 3.42 and 3.08 with the 6-sped (only choices from factory)
 
Those 4 codes came from the resources section of the website (actually the 2007 and newer RPO codes sticky at the top of the section this thread is posted in); I figured it was correct.
 
Sweet... hopefully i have the 4.10 ratios... its dark so I'm not walking out to check right now haha...

Yes i have plans for a Programmer, Intake, Throttle body spacer, and Exhaust.

The exhaust is last though cause I'm running straight pipes with the Cats still on. But not muffler and resonator >:)

You guys are awesome. I'm finally getting some clear answers. And I'm just gonna get my spedo recalibrated or whatever they do when you lift it so i don't need a programer right away do i? the whole lifting thing is new to me so if i have a stupid question sorry haha.... What do you guys/girls think of the Bully Dog chips and programmers? I've always heard good things about them but thats on Fords mostly and no one around here has an avalanche that isn't bone stock so talking to people around here is pretty useless :help:


PS. This is the best forum i have been on/read ever  (y) (y)
 
4.10 in a 07 is highly unlikely unless you have a towing package.

You will need a after market programmer for 4.56 gear, the dealer can't do that.
 
I bought it used with the chey towing package and from what ican tell it was used for towing A LOT so maybe things will work out nicely

Since im findin out about all this extra stuff... What about brakes? What are some good brands yalld recomend??
 
CJMOFFAT said:
I bought it used with the chevy towing package and from what I can tell it was used for towing A LOT so maybe things will work out nicely
Click to expand...

Just because it has a hitch does not mean it's a towing truck, do you have a tranny temp guage or a tranny cooler. You bought it used so I have to ask the questions
 
The only tranny temp gauge is when I scroll through the views where the odometer is but theres not on thats constantly visible unless i leave it on that.

Yeah I know that it doesn't make it one but it gives me a little bit of hope that i may have the 4.10 ratio so im not totally SOL on my power and gas milage.


As far as someone lifting a 2X, you'd be surprised how many people do it. I agree with you as far as it being pretty silly. But then there are probably quite a few people who think I was pretty silly for trying to make a 6000 lb. truck that will outrun quite a few pony cars.
Click to expand...

Yeah I know people do it but I think it just defeats the purpose of a truck to have it only 2wd in the first place and then lifting it? I don't understand it :beating: but I also don't understand doing huge rims but to each their own.
 
CJMOFFAT said:
The exhaust is last though cause I'm running straight pipes with the Cats still on. But not muffler and resonator >:)
Click to expand...

That can hurt mileage and power with the 5.3L motor, not enough back-pressure.
 
MyBigToy said:
Those 4 codes came from the resources section of the website (actually the 2007 and newer RPO codes sticky at the top of the section this thread is posted in); I figured it was correct.
Click to expand...

Well technically they are all for 07 or new AVs except "GU5      Rear axle, 3.23 ratio" should be 3.08 since the Chevrolet.com sight says they come with 3.08 standard or the optional 3.42.
 
I have some stuff to give me back pressure... Some sections of smaller pipe... Wait no i take that back... I have it cut off right after the flange... Im about to get a gibson dual extreme on there though... And i havent lost any mileage from it


And Ive checked i have the 3.73 gears.
 
just read thru this thread, I am getting a BDS 7" high clearance lift put on my 02 avalanche 2500 (32" tires as of now) in the next couple weeks and will be getting 35" tires in a couple more weeks following the lift install. I believe it has the 3.73 gears in it, atleast the code in the glove box matches the 3.73 gear code you all have posted. My question is, will I also need to re-gear my Av? even tho it has the 496 (8.1L) in it?
 
Unpredictable419 said:
just read thru this thread, I am getting a BDS 7" high clearance lift put on my 02 avalanche 2500 (32" tires as of now) in the next couple weeks and will be getting 35" tires in a couple more weeks following the lift install. I believe it has the 3.73 gears in it, atleast the code in the glove box matches the 3.73 gear code you all have posted. My question is, will I also need to re-gear my Av? even tho it has the 496 (8.1L) in it?
Click to expand...

wow i just looked at that BDS kit, looks very nice and actually not a bad price for 7"
The 4L80 has a slightly lower (higher) 4th gear than the 1500s 4L60 has, and lots more torque than the stock 5.3L.. That being said, i would still say 4.10s are better with 35" tires, because of all the benefits mentioned earlier in this thread. 4.56 gears would be more like stock power with the 35" tires, but it requires a carrier change - the 4.10 can be installed in the stock rear/front end. 
Looking forward to seeing your truck with the lift done, good luck!
 
which brand ring and pinion? I was looking at the yukon brand. 4.11 is what ill prolly go with. I was looking at them online, what is the difference in the GM9.5 or GM10.5? will they also be same part # for front and rear?
 
Unpredictable419 said:
which brand ring and pinion? I was looking at the yukon brand. 4.11 is what ill prolly go with. I was looking at them online, what is the difference in the GM9.5 or GM10.5? will they also be same part # for front and rear?
Click to expand...

Yukon is a good brand, that's what I'll be getting when I regear my rig. 

The gm 9.5 or 10.5 is righ gear size/diameter.  To the best of my knowledge the 9.5 is the semi-float 14bolt, where the 10.5 and new 11.5 behind the Dmax/ally are both full-float.  Best check your rear axle and confirm before ordering. 

They will be different part #'s for the rear, and front, depending on what model you got.  So if it's a 2500 with the 9.25IFS you order and a 9.5 14bolt semi-float your order accordingly.

If your looking to regear you might consider a better locker while you got the case cracked open... 

My .02 Cents
 
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