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Towing

Rug38

Full Member
Joined
Nov 16, 2020
Messages
9
I have a 04 avy z71 4x4
Was trying to figure out what are my options for transmission swap for a new model 2005-2020 better tow mpgs and stronger since I will be full time rv for some time about 2 years so I’m towing a lot tt will be about 6k
 
2003-2006 will have the same tranny.
Replacing tranny does not increase towing capacity.

2007 is when they started having options for different trannys like the 6 speed but came with different engines options

What rear end gear do you have as that can give you a few extra hundred pounds towing as does an equalizer hitch.

Doubt any mode will increase mpg when towing other then a diesel or 2500 version.
 
Regular towing near capacity with a 16+ year old tow vehicle may not be your best possible choice.

The 4L60E transmissions are not known to be the most durable.

The rest of the driveline and braking system in your 2004 has also aged.

Most likely, the wisest choice for heavy and regular towing, like you describe, would be to search for and purchase a tow vehicle better designed for the task.

If you insist upon only driving an Avalanche, a first generation 2500 series would make a much better choice for a tow vehicle than a 1500 series truck.

However, even though the 2500 Avalanche will be far more capable in terms of the weight being towed, the fuel mileage will be worse than what you are experiencing now.

Gas engines just aren't known for delivering the best fuel mileage when pressed.

Fuel mileage when towing is usually better with a diesel setup and the driveline hardware tends to also be more robust.

The right tool for the job is never a bad idea.
 
2003-2006 will have the same tranny.
Replacing tranny does not increase towing capacity.

2007 is when they started having options for different trannys like the 6 speed but came with different engines options

What rear end gear do you have as that can give you a few extra hundred pounds towing as does an equalizer hitch.

Doubt any mode will increase mpg when towing other then a diesel or 2500 version.
4.10 I know it wont increase the capacity I just was asking if the more robust design and larger (more gears) would make a difference
 
4.10 I know it wont increase the capacity I just was asking if the more robust design and larger (more gears) would make a difference
Sorry 3.73 rear end I do have the 17 rims so will be rebuilding the brakes with 07 parts and redoing the lines
 
Many owners who tow have been happy with a Magnussen supercharger on their stock AV. It gives more torque in lower rpms but doesn't hurt gas mileage unless you really stomp on it. In effect it helps you get to cruising speed quicker.
 
Is the 4L65E better and bolt in
From wiki:
The two transmissions cannot be differentiated from the outside. The 4L65E shares the same exterior parts but have stronger internals such as 5 pinion planets compared to 4 in the 4L60E. 4L60E uses a 6.5" depth bell with 6 bolts for non gen 3 LS applications and a 7" depth bell with 7 bolts for LS applications. The 4L65E/70E uses a 7" depth bell and 7 bolts.
 
The 4L65E in my 2004 EXT went bad on me with burned out 3-4 clutches at 125K.

The EXT has the factory aux transmission cooler.

The 4L60E in my 2003 Avalanche has 250K on it with no service issues, so far.

The Avalanche does not have a factory trans cooler installed.

I know from my research that the EXT lived it's early life on an Indian reservation in Oklahoma and was used for trailer towing.

It had a trailer brake controller installed when I got it and the rear bumper is well used and abused.

I found hay, dirt, bullets and other ranch debris all over the truck when I first detailed it.

The Avalanche was not used to tow anything more than a rare duck boat during duck season.

I'm not sure what, if anything, that all means.

But I thought I would just throw it out there.
 
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