4 Speed vs 6 Speed...what's the difference? How does it work?

I have had my '17 Taco SR5 DCSB since Thanksgiving and have been messing with the 4 speed vs 6 speed.

1) At first I did not under stand it coming from a Wrangler where what gear I "Manually" shifted to (in sport mode), the car would be in that gear. But it seems that my TACO works different. It seems that the 6s shifter tell the car how many gears it can use, not what gear it is is. AKA I put it into drive and double tap up to get the 6 speed but clearly i am still in gear 1.

2) I have been testing which gets better MPG. I drive about 50 miles a day (mostly highway). My findings are that 6s gets better mileage 90% of the time while the 10% is high speed highway travel for very long distance (75mph for 70 miles about).

3) In 4s, going up a hill and then down a hill and being around 3000 RPM....on the downhill the TACO downshifts at weird times therefore revving the engine obnoxiously. This does not happen when i do the same hill at the same speed in 6s....I just do not understand this and the other gear shifts that happen.



INFO: Taco since Thanksgiving with about 3700 miles.


feel free to answer any or all of those points with the # of the question in your post. Hopefully this is all comprehensive...if not oh well.

Thanks

 

1) The sport mode is just a gear limiter. What ever you tell it to go up to the trans still is an automatic and will shift appropriately to that max gear selected.

2) 5th and 6th are overdrive gears, however, no matter what vehicle, at 75 mph you will loose some mpg.

3)???