4L80 Tranny??

[AssKickinHD]

Whats the difference between the 4L60 that comes in the 1500's and the 4L80 that comes in the HD's? What makes it heavy duty? Any good info on it?

 

[RyanbabZ71]

check this out.  It has some of the technical info on gm trans

 

http://www.gm.com/automot....dex.htm

[QUIKAG]

Cool link, thanks!!

[Professor]

If you are used to the older stuff:

The 4L80 is basically a turbo 400 w/overdrive

The 4L60 (and the older 700R4) is basically a turbo 350 w/overdrive.

[AssKickinHD]

So should it hold up pretty well to towing and a set of 35" tires??  

[Professor]

You'll lose some on the GCVW due to the gear ratio change with the tire size. A 4L80 should hold up with moderate towing loads. The HD comes stock with 4.10, Use the trailering chart for the 2500LD and 3.73 gears.

 

Almost forgot...The 1st gear is also lower in a 4L60 than a 4L80.  The 4L80 has been used for at least 10 years. It is a good tranny.