Will 5.3 to 6.0 (LQ4) make a big difference in towing?

[Mudsport96]

Im in the gear ratio advantage camp. Yeah a 6.0 makes more power everywhere but at what point do you stop adding.
The trans is the next weak link, so now you have to repace it when it breaks. Do you go back to a 60e? A 65e? Find a 70e? Yes you can use a 70 in a 60 application with minimal effort to swap from what ive read.
Or take the big jump to an 80e? Wiring, tune, driveshafts.
Find out what gears put you at a good towing rpm and get those.
Personally, if its mainly for towing the boat, i would go straight to 4.56s. More mechanical advantage everywhere. And has the added bonus of taking some load off of the transmission because of the ratio increase, making it easier to move the load.

 

[George B]

I am also in the lower gears camp.

 

[THarber]

wrong post

 

[Teamwieland]

I tow with an LQ4 in my 2006 Denali xl and I also live in the mountains. Town sits at about 7,000 feet in elevation. While my towing has not gone over about 4500lbs, my LQ4 and my rebuilt 4L65E trans handle the boat I haul up and down the mountain roads for a close family friend, pretty easily. I’m not necessarily winning any speed races going up the grades when I’m towing but it pulls and pulls and pulls faithfully and doesn’t struggle. All I’ve done under the hood is a spectre intake, and a mild magnaflow muffler in pace of the factory muffler, and had blackbear performance do a tune. That’s a piece of the puzzle I would absolutely recommend. He tweaked a lot and adjusted for being at altitude most of the time. Here’s what I tow most often behind my Denali.

I’m at about 7000 lbs, plus the Suburban is usually loaded with 7 adults and all the stuff that goes along with it.

 

[Teamwieland]

What kind of altitude are we talking about? I appreciate the feedback from @adventurenali92 , but to be honest, the mountains in Ca. altitude are a whole different ballgame. We start out at 5280, and go up from there (5,861 here in my town). Once you head to the mountains, we’re usually at 10k+ pretty quickly. So I think that’s a pretty important piece to the puzzle.

From a quick glance, I’d say gears are the cheapest, most effective option to make a dramatic difference. Not that I don’t also want to swap an LQ4 in my ride…

My house is at 7600', and we usually go up to Denver at 5280. I'm wanting to go to Lake Powell before it turns into a small pond but I need to get over Eisenhower Tunnel which is over 11000' and Vail Pass.

 

[Teamwieland]

I do like the gears idea, although I've got 3.73s already. Since my motor has almost 230k on it already, it's got to be getting a little tired as a lot of those miles were pretty tough. I've got a line on a few LQ4s already and think it makes sense to try that route first. On a 4x4 I have to think a gear swap is at least $2-3k.

 

[Teamwieland]

I just looked up the towing capacity for 2003 GM full size vehicles. Interestingly, the main difference in capacity, whether 5.3 or 6.0, or 1500 or 2500, is rear axle ratio. Very little difference (few hundred lbs) between 5.3 and 6.0. Considering my 5.3 should tow 7400 lbs (at or near sea level presumably), getting more power should get me close to where I need to be with the new boat.

 

[adventurenali92]

I just looked up the towing capacity for 2003 GM full size vehicles. Interestingly, the main difference in capacity, whether 5.3 or 6.0, or 1500 or 2500, is rear axle ratio. Very little difference (few hundred lbs) between 5.3 and 6.0. Considering my 5.3 should tow 7400 lbs (at or near sea level presumably), getting more power should get me close to where I need to be with the new boat.

Nice boat setup! She’s a beauty!
I had four GM 6.0 equipped SUVs belonging to the family that I was living with at the time(my youth pastor and his whole family) when I decided to jump into a GM full size. I knew I loved the three Denali Yukon XLs, but my first thoughts were “do I really need a Denali, with the bigger engine?!” So I looked at Z71 package suburbans and SLT package Yukon XLs. Until i went and test drove a non Denali Yukon xl and knew the 5.3 wasn’t gonna satisfy me, especially knowing in my head I was gonna be pulling that sea ray for quite a bit more than I already was. I had driven the three Denali package Yukon XLs previously over the course of detailing them all and already knew the feel of the 6.0, and that was kinda it for me. When I found mine and I was everything I was looking for, that was all there was to it. Lol. Fortunately my Denali was already factory equipped with 3.73 gears.

 

[S33k3r]

If you are going to go through the engine, why not upgrade the LQ4 to LQ9 specifications? I think there are only three components' worth of differences -- pistons, rods, and something I forget. DISCLAIMER: No an engine builder -- I just read a lot. I also forget a lot... :-(

 

[Teamwieland]

LQ9 is higher compression and requires premium.