Reaction Elements in a 6L80


#1

This is a question about a 2014 Chevrolet Silverado pickup. I am studying the power flow of a 6L80 six speed automatic transmission. I can see the reaction elements for 1st, 2nd, 6th, and reverse gears. However I am having difficult with the reaction elements for 3rd, 4th, and 5th. Can you help? This sounds like a good question for Transman614.

Second question, what is the improvement in fuel economy between the 6L80 behind a 350 ci engine against a 4L80 behind a 350 ci engine, both with the same rear ratio; the same diameter tires and vehicle weight?


#3

transman hasn’t been active on this website in quite awhile

You’ll have to send him a personal message, I would think

otherwise, he won’t even know you’ve got a homework assignment for him


#5

The difference with the 5.3L LS motor isn’t tremendous
https://www.fueleconomy.gov/feg/Find.do?action=sbs&id=24511&id=25576
and
https://www.fueleconomy.gov/feg/Find.do?action=sbs&id=25584&id=24530

I suspect that the 6 speed truck would be noticeably quicker than the 4 speed truck, and that improved peformance was the driving force behind the change. GM’s compeititors went to 5 and 6 speed transmissions around the same time, if not sooner. Ford went to a 6 speed in 2009, Dodge had a weird 4/5 speed transmission with two 2nd gear ratios (one for upshifts and one for downshifts) as early as 2002 and had a proper 5 speed automatic in 2003 with a 6 speed automatic showing up in 2012. Nissan had a 5 speed automatic with the first Titans in 2005, and Toyota has a 6 speed automatic in their Tundra as early as 2007.


#6

I don’t know about power flow but every additional gear in a transmission improves fuel efficiency. There are diminishing returns as the number goes from 6 to 8 to 9 to 10 speeds.

If you want real numbers, GM went from 4 speeds to 6 in the mid 2000’s with few other changes. Look to the trucks with 5.3 liter V8’s since 350’s never got 6 speeds. They were gone by then.


#7

Was 2009 not the first year for GM to use the six speed? I had a 2008 Sierra for a short time. It had the 5.3 and a 4 speed.

I’m interested in what the plan is to get the 350 and the 6l80e to work together, if that is the plan. My truck has a 4.8 and I’d be interested in swapping in a six speed. GM never used the six speed with that engine for whatever reason. From what I’ve gathered, getting the electronic controls to work together is over my head and it would be more practical to just buy a truck with the 6 speed in it already.

OP, have you found anyone else that’s done the 350 with the 6l80?


#8

I finally figured out the reaction element for the 2, 3, 4, 5 and 6 gears. It appears to be the gear on the tail end of the stater mount. I still have not figured out how it is done but I am still researching.