As some of you know from other threads I am trying to help my FIL find a Sequoia for grand kid duty.In doing general research I looked into the ratios of the 2005+ 5-speed (behind the 4.7) vs the newer body style's 6-speed (behind the 5.7) to see how much of an "edge" the newer 6-box brought to the table. I was surprised to learn that the 6 is just the 5 with an extra OD ratio-- no deeper first gear, identical ratios.Current gen 6-speeds are thought of as the cat's meow for towing, but if the vehicle in question is a Sequoia, there's no advantage to be had there except running empty on the freeway.No question that 6's have advantages over older 4's, but over 5-speeds- especially in Sequoias specifically- there's little to be gained by having the 6-speed.Just found it interesting; I expected a deeper 1st & different ratios but not in this case.

The overdrive would be an advantage when the vehicle is not towing which for many folks is the majority of the time.

Interesting. I know that is not the case with my GMs 1500's, as all the gear ratios are reworked. But that is going from a 4 spd to a 6 spd.It should help with your unloaded mpg quite a bit, though. My 6 spd '10 gets about 3 mpg better than my '05 did on the freeway (20-21 mpg vs. 17-18 mpg in the old one).

And then ther are the Allisons that are six speednwith sixth locked out making it a five speed.

It has always been the final ratio at pavement vs engine rev'sAll of the gear boxes in the drive train only factor it...yes the diff is botha differential and one speed gear boxFor us old time boy racers...these high number of gears are just close ratiogear boxes of old...with double OD and wonder if there is a triple OD out there?

The Allison 1000 GM uses started with 5-spds, and added a 6th while retaining the same ratios 1-5.Dodge/Ram has played a few tricks with its 4turned5turned6 speeds as well.What did Toyota do with the axle ratio? If it is the same, then lower engine speed on the highway unloaded is all you will see, maybe a little less fuel used. If the axle ratio was shortened (numerically higher), then you may get an improvement in gears 1-5 while retaining a 6th gear equivalent to old 5th.

Surprising discovery: 5-speed vs 6-speed automatic

bmanning
Explorer
Aug 20, 2013
BurbMan wrote:
bmanning wrote:
No question that 6's have advantages over older 4's, but over 5-speeds- especially in Sequoias specifically- there's little to be gained by having the 6-speed.

All things being equal I would agree, BUT, you can't look at just the transmission....maybe the 6 box Sequoias came with a higher (numerically) rear axle ratio than the 5 boxes...That would give them more towing grunt, while the extra OD at the top end gives them the same highway mileage as the 5 box models.

I'm no Sequoia expert and not sure if Toyota gives you the option of several rear axle ratios, but since you've got this much info I would look into the rear axle options as well.

I believe Sequoias all get a 4.10 rear regardless of model year.

My 2002 Land Cruiser had a 4.30 and launch was excellent even with the older 4-speed automatic with a relatively high 1st gear ratio.

My XC90 V8 has a great launch also despite a 3.20 diff; a 4.15 1st gear makes up for it.
wilber1
Explorer
Aug 20, 2013
The ZF 8 speed used by Chrysler and many European makes is a six speed with double OD.
time2roll
Nomad
Aug 20, 2013
Is the differential ratio also the same?
BurbMan
Explorer II
Aug 20, 2013
bmanning wrote:
No question that 6's have advantages over older 4's, but over 5-speeds- especially in Sequoias specifically- there's little to be gained by having the 6-speed.

All things being equal I would agree, BUT, you can't look at just the transmission....maybe the 6 box Sequoias came with a higher (numerically) rear axle ratio than the 5 boxes...That would give them more towing grunt, while the extra OD at the top end gives them the same highway mileage as the 5 box models.

I'm no Sequoia expert and not sure if Toyota gives you the option of several rear axle ratios, but since you've got this much info I would look into the rear axle options as well.
APT
Explorer
Aug 20, 2013
The Allison 1000 GM uses started with 5-spds, and added a 6th while retaining the same ratios 1-5.

Dodge/Ram has played a few tricks with its 4turned5turned6 speeds as well.

What did Toyota do with the axle ratio? If it is the same, then lower engine speed on the highway unloaded is all you will see, maybe a little less fuel used. If the axle ratio was shortened (numerically higher), then you may get an improvement in gears 1-5 while retaining a 6th gear equivalent to old 5th.
BenK
Explorer
Aug 20, 2013
It has always been the final ratio at pavement vs engine rev's

All of the gear boxes in the drive train only factor it...yes the diff is both
a differential and one speed gear box

For us old time boy racers...these high number of gears are just close ratio
gear boxes of old...with double OD and wonder if there is a triple OD out there?
nevadanick
Explorer
Aug 20, 2013
And then ther are the Allisons that are six speednwith sixth locked out making it a five speed.
Tystevens
Explorer
Aug 20, 2013
Interesting. I know that is not the case with my GMs 1500's, as all the gear ratios are reworked. But that is going from a 4 spd to a 6 spd.

It should help with your unloaded mpg quite a bit, though. My 6 spd '10 gets about 3 mpg better than my '05 did on the freeway (20-21 mpg vs. 17-18 mpg in the old one).
Road_Ruler
Explorer
Aug 20, 2013
The overdrive would be an advantage when the vehicle is not towing which for many folks is the majority of the time.

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Surprising discovery: 5-speed vs 6-speed automatic

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