What gears are factory and what should I run ?

[Jonpen]

I have an 07 Yukon Denali and it’s lifted 7” with 22x14 on 37s , what are the factory gears and what gears should I run

 

[Doubeleive]

I have an 07 Yukon Denali and it’s lifted 7” with 22x14 on 37s , what are the factory gears and what gears should I run

rpo code list in the glove box will show the ratio but generally the denali's are 3.42 oem.
it couldn't hurt to run 3.73 but there is cost involved unless you know how to do the ring & pinion, the front diff could be swapped out for a 3.73 it would be cheaper than tearing down. need to do this on my silverado but dragging my feet
@swathdiver

 

[AJMBLAZER]

At least 4.56’s. You’ve gone for a much bigger and heavier tire than OEM plus the aerodynamic drag imposed by the lift.

 

[TollKeeper]

I dont think I would go larger than 4.10, unless you are actually running off road.

It would come down to intended use of the truck.. Is this a mall crawler with the look of off-road, or is this actually used off-road.

Not judging you here, but honesty here will help you get the best results.

 

[OR VietVet]

With that big a tire and the ratio difference that causes, if in town the 4.10 gears would be my choice but if off roading, a 4.46 gear. I had a purpose built 73 Blazer with 1 ton axles and I had 38" tires and only off roaded with it, trailered to trail heads, with 4.88 gears. You will have to do both ends and will get pricey.

Welcome to the forum.

 

[Jonpen]

I dont think I would go larger than 4.10, unless you are actually running off road.

It would come down to intended use of the truck.. Is this a mall crawler with the look of off-road, or is this actually used off-road.

Not judging you here, but honesty here will help you get the best results.

It doesn’t do much off-roading , so if I go to 4.10 do I have to change the carrier as well or can I just get a re gear kit , sorry not very mechanically inclined

 

[Doubeleive]

It doesn’t do much off-roading , so if I go to 4.10 do I have to change the carrier as well or can I just get a re gear kit , sorry not very mechanically inclined

at 4.10 you might "maybe" find a front one out there already geared, but otherwise ring & pinion for the rear and not sure what is needed for the front but it cost's more to re-gear it than to just swap it out.
most of your cost is going to be labor parts are not that much a used front diff runs around $650 to rebuild/regear it is twice that

 

[Jonpen]

Yea I found a kit for 1,300 for both front and rear , just wanted to make sure I didn’t need a bigger carrier

 

[Marky Dissod]

I have an '07 Yukon Denali and it’s lifted 7” with 22x14 on 37s.
What are the factory gears?

Look in your glovebox.
M30 = 4L60E

GU6 = 3.42
GT4 = 3.73
GT5 = 4.10

 

[swathdiver]

I have an 07 Yukon Denali and it’s lifted 7” with 22x14 on 37s , what are the factory gears and what gears should I run

Your Denali has 3.42 gears and if you want to have about the same effective ratio (a little lower) with 37s run the 4.56s.

You do not need to change carriers in either axle for up to 5.13 gears.

You may want to consider getting the larger rear axle from the RWD Denalis and Escalades, 2007-2013, the 9.5" 14-bolt semi-floater. That can often be had for a song at LKQ. Again, that carrier will handle up to a 5.13 gear.

Remember that those AWD transfer cases demand that the tires be within 1/8 inch in height of each other.

 

[j91z28d1]

Your Denali has 3.42 gears and if you want to have about the same effective ratio (a little lower) with 37s run the 4.56s.

You do not need to change carriers in either axle for up to 5.13 gears.

You may want to consider getting the larger rear axle from the RWD Denalis and Escalades, 2007-2013, the 9.5" 14-bolt semi-floater. That can often be had for a song at LKQ. Again, that carrier will handle up to a 5.13 gear.

Remember that those AWD transfer cases demand that the tires be within 1/8 inch in height of each other.

I was going to say there's a gear calculator online. just punch in before and after tire size and it will spit out what gear you need to run to keep the stock ratio..

going rised big tire off road is kinda like going drag racing. it's very expensive if you're not doing it yourself. Maintaining the mods also goes up a lot. as everything wears faster and breaks sooner.

both are fun thou. good luck.

 

[OR VietVet]

Knowing what you just said about being mechanical, do not try to do the work yourself.

 

[swathdiver]

I was going to say there's a gear calculator online. just punch in before and after tire size and it will spit out what gear you need to run to keep the stock ratio..

going rised big tire off road is kinda like going drag racing. it's very expensive if you're not doing it yourself. Maintaining the mods also goes up a lot. as everything wears faster and breaks sooner.

both are fun thou. good luck.

I made a calculator with excel that's very precise and even accounts for tread depth. Here's an example of my compact one:

This is about what the OP is experiencing now:

And this is how his truck would perform with 4.10 gears:

So if you compare the before and after, you guys were correct and I was wrong about the 4.56s being more equal, the 4.10s would be more equivalent while running 37s!

That's why I made this! LOL

 

[Jonpen]

Your Denali has 3.42 gears and if you want to have about the same effective ratio (a little lower) with 37s run the 4.56s.

You do not need to change carriers in either axle for up to 5.13 gears.

You may want to consider getting the larger rear axle from the RWD Denalis and Escalades, 2007-2013, the 9.5" 14-bolt semi-floater. That can often be had for a song at LKQ. Again, that carrier will handle up to a 5.13 gear.

Remember that those AWD transfer cases demand that the tires be within 1/8 inch in height of each other.

Can you explain to me a little more what you mean the tires have to be within 1/8 of each other

 

[Jonpen]

Knowing what you just said about being mechanical, do not try to do the work yourself.

I have a mechanic

 

[swathdiver]

Can you explain to me a little more what you mean the tires have to be within 1/8 of each other

The tire heights have to be as close as possible to prevent damage to the axles and transfer case. You don't want tires on the same axle to be different heights nor do you want there to be more than 1/8 inch different in height between tires on the drive axle compared with the tires on the steer axle. This will cause the tires to be turning at different rpms causing undue stress on the clutches in the locker when engaged and in the planetary in the transfer case in your case.

 

[Jonpen]

I made a calculator with excel that's very precise and even accounts for tread depth. Here's an example of my compact one:

View attachment 402949

This is about what the OP is experiencing now:

View attachment 402953

And this is how his truck would perform with 4.10 gears:

View attachment 402954

So if you compare the before and after, you guys were correct and I was wrong about the 4.56s being more equal, the 4.10s would be more equivalent while running 37s!

That's why I made this! LOL

Does that also include having the 22x14 wheels as well ?

 

[AJMBLAZER]

The wheels make no difference other than adding weight the truck has to spin.

 

[Dustin Jackson]

I’ve been told that my 3.73 gearing wasn’t enough for my 32 inch tires

 

[Marky Dissod]

GM under-gears nearly everything they make - trying to satisfy CAFE MpG tests and avoid fines.

... been told that 3.73 wasn’t enough for 32" tires

4.10 would DEFINITELY be better - city MpG would improve, enough to overcome the highway MpG penalty, at least for me.

... So if you compare the before and after, you guys were correct and I was wrong about 4.56 being more equal, 4.10 would be more equivalent while running 37s!

If 4.10 is 'more equivalent' to GM's OE gearing, then 4.56 would be better.