Older Model Short Tahoe vs. Suburban For Towing

Yeah I'd avoid AFM but it is possible to disable / remove. [I wonder if you could get a deal on a vehicle with bad AFM? then slide in a better cam. More work I know, but maybe you can get a good deal going this path.]

I think, and going off memory, when the 6AT came out, it became harder to get "good" rear gearing. Thing is, it became less important. The 4L60 and related had a 3.06:1 first gear. The 6AT's were like 4:1. That deeper first gear ratio "makes up" for the rear end being a bit taller. That said, I always thought 3.42 was a bit too tall, and 3.73 was better. I'm just not sure if you could get 3.73's.

Casual looking and I almost never see the build sheet / RPO codes given. A few sites will state what the rear gears are. If you can get the VIN though, there is a VIN lookup site that will tell what that truck got for rear gears. I think I usually find it under "GM VIN decoder". That's for if you are doing online shopping--if you are going in person, jot down the RPO codes for the rear gears and have that handy, and find the RPO sheet (is it still in the glovebox?).
Couldn't have said it better!

In SUV form 2000-2006 would be Generation III LS-based which is a 24x crank and 1x cam gear. No AFM in these engines. 2007-2014 would be Generation IV LS-based which is 58x crank and 4x cam gear. Some of these have AFM.

Don't forget you have the Cadillac Escalade ESV as your Caddy Suburban variant.

In 2001-2006 Yukon XL Denali's came with the LQ4 6.0. They do have an AWD transfer case. Additionally, similarly, yet different 2003-2006 Escalade ESV's came with the LQ9 6.0. Same thing, AWD transfer case.

Also, the 2006 Suburban LTZ (kinda a unique model/trim/config for the year), has a LQ4 6.0, AWD transfer case, special interior and other body items. Think of it as a close cousin to the Yukon XL Denali.

In all 2000-2006 1/2-ton GM SUVs, you'll have a 4L60e, 4L65e in the Caddilac and Denalis.

2007-14 trucks -- 2007 and 2008 you will again have a 4L60e, 2009 and up will have a 6L80e. 2009 and up you also have a potential for a 6.2 V8. All Escalades from 07-14 are 6.2 with a 6L80e. I don't know for sure but think the 6.2s in the Escalades were without AFM.
 
Is the 6.0 L with 4 speed 3:73 gearing as dependable for towing as the 5.3 with 4 speed 4:10 gearing?
Is the 6.0 as easy to work on and as dependable as the 5.3?
Fuel economy of 6.0 vs 5.3?
How about the AWD on the Denali's? I am not sure about full time 4WD vs 4x4 on demand. Seems like more wear and more parts to break to me.
I love my '03 5.3 from a mechanical perspective. very easy vehicle to work on and has been very dependable so far, other than fuel pump, rear main and some typical GM dash and headliner issues.
I have a lead on a low miles (70k) 2005 denali. 15k asking price - still seems pretty high, but if I can get the type of mileage out of it as I get from my Suburban, may be worth it.
 
Regarding gas mileage, I have a 2008 3/4 ton Burb with a 6.0 and 6 speed transmission and Auto Trac 4WD selectable in 2WD, 4WD or Auto. Driving on a level road with at 60 mph would yield about 9 mpg with a 6300 lb travel trailer. There was no use trying to tow in 6th gear, and I would use the manual button to hold it in 5 th. It has a 3.73 rear end. Going up a grade meant shifting into 4 th. RPM would be 3200-3500. The LS engines are made to rev, not like Grandpa’s 454. Gas mileage at 65 mph is about 15 mpg without the trailer.
 
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Ooh almost forgot, 2007 model year only, the 3/4 Suburban... new body style is a Generation IV 6.0 with a 4L80e. One year only.
 
Is the 6.0 L with 4 speed 3:73 gearing as dependable for towing as the 5.3 with 4 speed 4:10 gearing?
Is the 6.0 as easy to work on and as dependable as the 5.3?
Fuel economy of 6.0 vs 5.3?
How about the AWD on the Denali's? I am not sure about full time 4WD vs 4x4 on demand. Seems like more wear and more parts to break to me.
I love my '03 5.3 from a mechanical perspective. very easy vehicle to work on and has been very dependable so far, other than fuel pump, rear main and some typical GM dash and headliner issues.
I have a lead on a low miles (70k) 2005 denali. 15k asking price - still seems pretty high, but if I can get the type of mileage out of it as I get from my Suburban, may be worth it.

AWD will use more fuel, No way around that other that converting in to 2WD;) The Borg Warner 4481 AWD Transfer Case is actually more reliable than the part time New Venture NV246.
Change the fluid in the front differential often on AWD models as it works all the time.

The 6.0L & 5.3L are identical far as serviceability, Service life is pretty much the same between the two......Outlast the vehicle usually.
 
Ooh almost forgot, 2007 model year only, the 3/4 Suburban... new body style is a Generation IV 6.0 with a 4L80e. One year only.
Also the 2009 Tahoe LTZ with the 6.2…..not sure if all Tahoe LTZs had those engines that year, but at least some did. Considered the unicorn of NBS Tahoes. Sellers often don’t know what they have and let them go for a 5.3 price :)
 
Is the 6.0 L with 4 speed 3:73 gearing as dependable for towing as the 5.3 with 4 speed 4:10 gearing?
Is the 6.0 as easy to work on and as dependable as the 5.3?
Fuel economy of 6.0 vs 5.3?
How about the AWD on the Denali's? I am not sure about full time 4WD vs 4x4 on demand. Seems like more wear and more parts to break to me.
I love my '03 5.3 from a mechanical perspective. very easy vehicle to work on and has been very dependable so far, other than fuel pump, rear main and some typical GM dash and headliner issues.
I have a lead on a low miles (70k) 2005 denali. 15k asking price - still seems pretty high, but if I can get the type of mileage out of it as I get from my Suburban, may be worth it.
My boss loves Yukon XLs. It’s all he’s ever bought since I’ve worked for him for 20 years. He buys them used with a lot of miles on them, and then drives them until the repair frequency gets too high. His two oldest ones probably lasted the longest, and by oldest I mean around year 2000. Idk the generations in these. I think one was a 97. Interior plastics became sad, and the rear end needed a rebuild, but mechanically it was solid and leak free. It made it about 225000 when recurring electrical issues took it down.

his second one, probably a very early 2000s model, was about equally long-lived. He traded it for another at around 200k as it was starting to show the same pattern- an increase in broken plastics, increase in small repairs, and after something that needed real work happened he started looking before it started needing more.

the newest one is probably around a 12? It has the bigger motor. the original engine shredded valve lifters around 150,000 miles on it, and his mechanic installed a jasper…. and then another jasper. at 215000+ where he’s at now, it drives solidly, though not luxuriously at all, and the interior rattles like a can of beans and to my hand the steering feels a little laborious. (I also can’t stand that GM couldnt center the steering wheel to the driver’s seat). Air still blows ice cold. It just got new air shocks for $1200 from the dealer. He bought a used f150 to protect the Yukon from doing the messy house restoration he’s doing. The ford is a significantly more comfortable and cleaner truck, but he still dailies the Yukon. Transmission shifting great on oem juice (I’m shaking my head, he’s scared to change it now).

if memory serves, there were improperly hardened camshaft complaints for a while innthe mid-00s to early 10s? Symptom was a mild stumble at idle, I’m not sure if there was anything worse. It happened with another friend of mine who was picky enough to care.
 
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