Hey guys i currently have an extended cab 2006 four-wheel drive 5.3 with the 4L60E transmission. I tow approximately 2200 to 2400 lb on a regular basis. I know that ...

Hey guys i currently have an extended cab 2006 four-wheel drive 5.3 with the 4L60E transmission. I tow approximately 2200 to 2400 lb on a regular basis. I know that is nowhere near the towing capacity of my truck. But this thing drives me nuts on the interstate shifting what feels like hundreds of times in a 2 hour trip. The slightest little hill that you come upon it will downshift two gears and the engine will be screaming like it's going up the side of a mountain. You absolutely cannot use cruise control. As soon as it loses 2 to 3 miles an hour it will down shifting gears again and start screaming until it gets back up to 70 and then upshift.
I've talked to several other Chevy owners with the same model year truck and they said theirs does the exact same thing. I have been doing some research and saw that the 2009 came with a 6-speed transmission. For those that have driven both does the 6-speed transmission shift constantly back and forth like the 4-speed does?
I know the 2009 had a revamped interior which I like a lot more than my 2006. I've been thinking about upgrading to a few years newer if that will help with the issues I am having. I cannot afford a new truck or even one that is a few years old. So I'm looking at possibly a 2009 to 2010 something around that year.
On another note my truck does go through probably a quart of oil between oil changes. I have read this is a very common problem with the 5.3 engines. What is the reason for this? I also have what I read is the very common piston slap when the engine is cold.
I have a buddy with the F250 and he swears up and down that his truck will pull a lot better than mine will. It's a 2008 with the 5.4 and claims his truck never uses any oil.
I like the Chevys better I just want to try to get the best bang for my buck. I definitely prefer the pushrod motor versus the modular motor. Does the 6.0 engine and transmission set up work that Much less than the 5.3 when towing?
Sorry for the long post but I would definitely appreciate any feedback

What gear ratio do you have in your truck now?

But in general, the newer trucks have some more power than the older ones, and the 6 speed transmissions definitely help.

It will still shift though, really the best way to stop that is to lock it out of overdrive. Shifting in and out of overdrive will absolutely kill the 4l60e. Run it in 3rd if it's doing that a lot.


And yeah, I'd bet the F*** 250 would out tow a 2500. At least I'd hope it would lol. Can't compare a 1500 to a 2500 platform. The HD trucks will run circles around the 1500s when it comes to towing. Their gearing is better, chassis handles it better, brakes are bigger, etc.

But in your case, that light of a trailer should be zero issue for your 06. Obviously if you have like 3.08 or 3.23 gears that is a big factor as to why it is shifting like crazy. 3.73 and 4.10 (mainly 4.10) are ideal for stock size tires on the 4 speed trucks. I had that combo in my 01 and loved it. It towed great and had nice pep around town when I wanted.

That makes alot of sense. To be completely honest i am not sure what gear ratio i have. I will see if i can find out what i have. I'm kind of at a crossroad now do I want to start dumping money into my truck that I like but don't love. Or do I try to get one a few years newer that has a much better interior in my opinion as well as stated more power and a better transmission. I don't want to start dumping tons of money into my truck when I don't feel it's really worth it. It has 208 thousand miles on it. What is a safe RPM to be cruising in 3rd gear down the interstate? Without overheating the transmission?

Well my 01, with 4.10s in it would run about 2100rpm at 70mph in 4th gear. I wouldn't be afraid to run 2000-2500 down the highway at all.

And your 06 is ahead of the gmt900 trucks in basically every way except for power. The gmt900 trucks are built cheap and it shows. Plus the 5.3 and 6.0 have AFM, which is a step backwards in the reliability department. Between the two choices, a gmt800, and a 900, I'd take a nice gmt800 any day of the week. You really only get nicer quality when you jump ahead to the k2xx trucks. The build quality is SO much better on them.

As far as gear ratios, look in your glove box for the silver sticker.

The gear codes are as follows.

GU4- 3.08
GU5- 3.23
GU6- 3.42
GT4- 3.73
GT5- 4.10
G80- Locking Diff

Ok just went and looked and it has gu6 and g80. Along with a ton more codes!!! Im a little lost with the truck references you made but i assume that the year range i am looking into 09/10 is what you referred to as the gmt900? I just cant afford a new or even few year old truck in my current situation unfortunately. But if one 3-4 years newer wont be much if any better it may not be worth looking into. I assume you mean the fit and finish being "cheap"?? Thanks for all the help and info. I really appreciate it

1999-2007 classic is the gmt800 and 2007.5-2013 is the gmt900

And yeah, the gmt900 build quality is pretty poor and the materials are cheap in my opinion. Plus you get the unreliability of AFM if you get a 5.3 or 6.0 (1500 only).

Really the only redeeming quality of the gmt900 trucks is the available 6.2 and the 6 speed trans. But I'd still take a nice gmt800 over a gmt900 truck. Just a more reliable, nicer built truck in my opinion. And a lot of guys will say they love their 900 trucks. And that's fine. They just aren't for me lol.

Thank you again for all the info. What exactly is the AFM you are referring to? Never heard that before.

It is a system that allows the engine to run on 4 cylinders instead of 8. It was dome to try and get better fuel milage, but often doesn't achieve that goal.

It is also failure prone. The lifters will fail, and ruin the cam, sending metal through the oil system. This can take out the entire motor if not caught right away. But it can happen fast with no warning signs. It also causes the engine to burn a severe amount of oil sometimes.

The only sure way to fix it, is to delete it entirely. This involves a new cam and lifters among other things.

cbibb wrote:Ok just went and looked and it has gu6 and g80.

I do believe it is because of your GU6 (3.42) gear ratio. I've pulled 2000-2500 lbs many times with my GT5 (4.10) gear ratio and rarely have it downshift (except on steeper grades...and I'm talking I-80 in Wyoming with elevation extremes of 5049-8640').

But as 19trax95 mentioned, that constant back and forth shifting is hard on the 4L60e transmission. Running it in 3rd will be better for the transmission.

i would shift myself and keep what you have. the engine will be fine even if you rev it hard when towing. you just have to get used to it.