6 speed 3.08 towing better than 4 speed 3.73??

Seapro21 · November 20, 2013

I am a little confused by the tow ratings of the newer Silverado's. I have a 2010 5.3, 6 speed, 3.08 with towing package. Normally, I wouldn't consider a 3.08 gear useful for towing anything more than a wagon. But as I have been reading more on the new 6 speed transmissions, it appears that the final drive ratio is more important than the engine (as long as it has adequate power). The 6 speed 3.08 combo has a better final drive ratio than my older 5.7, 4 speed 3.73 geared truck. The 4 speed 3.73 was a pretty good tow vehicle for a half ton and would pull anything I put behind it. I am curious if all the bad comments on the 3.08 as a towing gear is based on the older 4 speed trucks and if the 6 speed actaully has a better towing profile as the numbers suggest?

Final Drive Ratio's:

6 Speed with 3.08 4 Speed with 3.73

1st - 12.38 1st - 11.41

2nd - 7.27 2nd - 6.52

3rd - 4.71 3rd - 3.73

4th - 3.54 4th 2.62

5th - 2.62

6th - 2.06

Chris · November 20, 2013

Well if you look at application, you dont tow in overdrive. So for the 4 speed you would tow in 3rd and have a 3.73 final drive, the 6 speed you would tow in 4th and have a 3.54 final drive.

I will admit by numbers the 6 speed/3.42 should do better than 4 speed/3.73

redwngr · November 21, 2013

As always, the devil is in the details. How far, how fast, how heavy and how often?

What speed and gear are you towing now? Are you towing local or on the highway?

If you need/want to tow in high gear, and your current rig can do that, then perhaps the 6sp/3.42 will give the same ratio, with the benefit of deeper reduction for getting the lower gears. If the 2.62 ratio is border line, the 6sp/3.08 may not hold in high gear.

madmantrapper · January 5, 2014

I have 5.3 6 speed with a 3.73 locker. I pull a 8,000+ lb trailer with a skid loader on it several times a week. I think it does great. I also have a dodge 4.? that don't pull for nothing.

Elbert · February 17, 2014

Generally for towing I look at the ratio of the rear end on the truck first. 3.73 would be the general ratio you would start at when considerting towing. The different transmissions add flexability..ie auto with 4 speed, auto with 6 speed, or on the older GM trucks different manual transmissions. 3.08 is not very good in the towing department. I know the different transmission gear ratios factor in to this as well. Generally speeking a 6 speed auto adds more ratios between start (1st gear) and OD (6th), so that the engine is more efficient. A good way to understand that is in the older pickups there is a pretty good rpm drop when you went into 4th (OD) and TCC kicked in.

Torque and the range of RPM where that torque come into play also adds to the capabiliyt of the towing truck. I see the notes on the final drive calculations but I think 3.08 is too low of a numerical ratio for towing. Of course the weight of what you tow and how often you do that would have bearing. If towing light I would want 3.42 and if heavy 3.73 on a half ton.