Dexron VI fuel efficiency?

[the skull]

All Right!!!!
I got a bunch of Dex/Merc hanging around up here just
begging to go in a tranny, I just changed the transfer case
fluid out an hour ago!!!

 

[98G]

They gained 4 mpg, which is nothing to sneeze at, but they had to do ALL the fluids to get that.


."[/QUOTE]

I am VERY impressed. Somewhere between a 10% and 20% increase in fuel economy, from reduction of friction. And this when most of the drag probably comes from aerodynamics. That's HUGE, and the most convincing endorsement of synthetics that I've seen...

 

[cbear]

In what vehicle? Was it a 3 ton brick?

 

[rustystud]

TexAndy, the transmission parts are NOT fully submerged in transmission fluid. The actual fluid level of the average transmission is only about 1/2" above the oil pan edge. The bulk of the fluid goes to the torque converter and cooler and lines. The rest goes to fill all the little passages in the transmission valve body and case. In fact when a transmission is over filled the rotating parts will whip up the fluid into a froth which is really bad ! Since froth does not pump ! When I was referring to the proper viscosity I'm also referring to the ability of the clutch plates to clamp together without too much slippage. Slippage is bad in a automatic transmission. The reason GM does not make Dexron III is the same reason they don't make TH400s anymore. They don't have too. No GM vehicle has used this transmission for almost 30 years now. Yes some trucks used it into the 1990's but only a few. So why continue to make fluid for a discontinued transmission ? Let the aftermarket do it. As far as being backwards compatible goes, how is that new Low "E" engine oil doing in your flat tappet engine ? It is also backwards compatible just ask the engineers. Granted your cam lobes will all wear out, but then you can buy a new roller camed engine ! Seems to me you have already made up your mind about using this newer fluid and that's OK. I just gave you free information I have learned from 35 years rebuilding these units. Since it's free you get what you payed for.