Rear axle, 3.08 vs. 3.42 Explaining the difference

WhiteMike · October 18, 2013

I'm in the market for the 2014 Sierra SLT. I have found a truck which includes all of the options I am looking for, but I realized it has a 3.08 rear axle ratio, instead of the 3.42 I normally see. Can someone please explain to me in laymen terms the difference and exactly how it factors in? I do plan on pulling a 24' boat and I just want to make sure I have enough power. How important is the difference of 3.08 vs 3.42? Even noticeable?

Thanks in advance.

Chris · October 18, 2013

If deciding for the boat(right away I would choose 3.42), what is the weight of the boat and type of terrain it will be towed on?

crushNchowda · October 18, 2013

I actually think most of the trucks - especially earlier builds - had the 3.08

I think this because I actually traded in y 3.08 2014 SLT on a 3.42 all terrain model because it felt neutered.

The gear ratio makes a whopping .6 second difference to 60mph

Get the 3.42 no matter what, it does lose 1 mpg but who gives a shit its a truck

Chris · October 18, 2013

I drove a 3.42 truck and it felt neutered. Not sure why? The 5.3 has numbers on par with my 6.0 stock for stock and I have a 4 speed 3.42

blckthree · October 18, 2013

If you have a boat to pull, get the 3.42. Drive them both, you will feel the difference. I'm sure your dealer has at least one of each for you to try out.

Mike

6.2max · October 18, 2013

I'm in the market for the 2014 Sierra SLT. I have found a truck which includes all of the options I am looking for, but I realized it has a 3.08 rear axle ratio, instead of the 3.42 I normally see. Can someone please explain to me in laymen terms the difference and exactly how it factors in? I do plan on pulling a 24' boat and I just want to make sure I have enough power. How important is the difference of 3.08 vs 3.42? Even noticeable?

Thanks in advance.

Its all about torque multiplication. The 3.42 is going to have more towing power (torque to the rear wheels) than the 3.08.

If your boat weighs more than about 5K, I would not want to be towing it with a 3.08.

GMC-AT · October 18, 2013

get the 3.42... and get the SLT loaded. Too many guys on here wishing they had this.. or had that after the fact. And the 3.42 is a common one....

WhiteMike · October 18, 2013

That's all I needed to hear.... I'm going to wait until the 3.42 comes available with all the options I am wanting. I'd estimate the boat is @ 4 - 5000 lbs. I live down here in Texas with relatively flat terrain except when I plan on pulling the boat to East, Tx where there are hills.

I'm not concerned about losing the 1 mpg. Heck, I'm coming from an old 2005 2500HD gas which avg. 12 mpg.

3.42 it is! Thanks guys.

crushNchowda · October 18, 2013

I drove a 3.42 truck and it felt neutered. Not sure why? The 5.3 has numbers on par with my 6.0 stock for stock and I have a 4 speed 3.42

Cuz you have a well broken in, bolted, tuned truck and you're comparing it to a factory fresh, bone stock, 2014 w/ all the torque mgmt dialed in.

These trucks are substantially more powerful throughout the rpm range compared to the old 5.3, and are comparable if not slightly ahead of the 6.0 you mention considering the tranny and direct injection.

I can wait to get a solid tune on mine

Chris · October 18, 2013

It felt weaker than my 4.8/4L60/3.42 did. But this 14 I drove was the day after my friend bought it. It just felt weak. Hard to explain

kstruckcountry · October 18, 2013

That acceleration vid looked pretty quick!

Chris · October 18, 2013

It had balls, but felt like it was shooting blanks. Best way I can describe it. It wanted to move, but was restricted. Too much TM maybe

kstruckcountry · October 18, 2013

My 2006 had a lot locked up. I can't imagine how much they're hiding on the new trucks.

Matt in Houston · October 18, 2013

It probably felt weak because the initial throttle sensitivity is really dialed back, I think to help with mpg. It works great when trying to keep it in V4 mode while cruising, but to make it really run you have to put your foot way down in it...then she will run.

It takes a few minutes for me to adjust after driving my truck all week and then I hop in my wife's SUV...I'm almost peeling out because the pedal is way more sensitive.