Quote:
Originally Posted by malibu
GM went with the 3.08 gears when they came out with the 6 speed trany. The 6 speed shifts through the first three gears quickly so the gearing can be higher or lower depending on how you look at it. The older trucks had 4 speed trany's requiring the 3.73 or 3.42. I have an 06 chevy with the 3.42 and with tow/haul mode its not bad when towing. It all depends on how much weight you are going to tow?
Think snow!
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I agree with Malibu. The 4 speed used in Silverado's was a 4L60 and had the following forward gear ratio's
1=3.06
2=1.63
3=1.0
4=.7
The 6 speed that replaced this is the 6L80 and is geared as follows:
1=4.027
2=2.364
3=1.532
4=1.152
5=.852
6=.667
The gears in the axles then determine the final gear ratio i.e. 4.10 or 3.73 etc. Look at the 4L60 ratio of highest gear to lowest gear versus the 6L80. Much wider.
By the way I also have an 05 Silverado with 3.42 gears and occasionally tow a 5,000 trailer (can you say large flat plate front) and used to tow my 21' Four Winns. The truck does it. But it is more optimized for daily driving. I drove to Mcadoo PA and picked up that trailer getting 20 mpg. Pulling it back I got 13 mpg.
This issue comes up all the time on an RV site I frequent. One thing I've noticed from that site, a lot of folks claim you need a 3500 diesel dually to pull a 2000 pound trailer.