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Discussion Starter #1
Hello everyone,

I'm wondering if anyone can explain the benefits of 6 forward gears. I'm assuming first gear will be smaller than the typical first gear in a 5 speed transmission and the sixth gear will be larger, like an overdrive for better fuel economy?
 

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Scribble,

You are correct on both accounts. The 6th gear can allow for better fuel economy as well as allowing for lower gears. As in the case with the 2005 Tacoma, Toyota opted for the lower gears rather than the better fuel economy. However "Better" in this sense is relative because the 6th gear allows the 05 Tacoma to maintain the same fuel economy as its older brother the 95-04 Tacoma.

Here is an example without getting into exact gear ratios and tire sizes: For my 94 Toyota Truck, 5th gear at 3200 rpm maintains 70mph. The 95-04 Tacoma in 5th gear at 70mph is moving along at 2600 rpm. Now the 05 Tacoma in 5th gear is much like my 94. At 70 mph in 5th gear you are close to 3100 rpm, but pop it into 6th and you drop to 2600 rpm. With the 05 Tacoma, Toyota was able to give us back our closer gearing that we long time Toyota truck owners had grown accustom to. Adding the 6 speed allowed Toyota to accomplish this without compromising fuel economy.

We can only speculate the gearing in the FJC will be similar to the new Tacoma (if not just a little smaller).
 

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Scribble said:
Hello everyone,

I'm wondering if anyone can explain the benefits of 6 forward gears. I'm assuming first gear will be smaller than the typical first gear in a 5 speed transmission and the sixth gear will be larger, like an overdrive for better fuel economy?
Not to mention,
6 speeds are just cooler than 5 speeds!

It looks like the 6 speed is the natural evolution in manual trannies. Everybody is going with 6 these days...even Jeep!
 

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Scribble said:
Hello everyone,

I'm wondering if anyone can explain the benefits of 6 forward gears. I'm assuming first gear will be smaller than the typical first gear in a 5 speed transmission and the sixth gear will be larger, like an overdrive for better fuel economy?

The same reason 5 is an advantage over 4 and 4 over 3.
 

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2005 Tacoma gearing info:
http://www.toyotaoffroad.com/Articles/Toyota/2005_Tacoma/2005_Tacoma_s.pdf

Driveability has everything to do with the 4-5-6-speed OD tranny discussion. Highway fuel economy is achieved with the overdrive, which is .85 with the 6-speed and .81 with the 5-speed....behind identical powerplants and in identical rigs, the 5-speed will cruise at a slightly lower rpm and have the potential to offer better fuel economy. Both are also 1:1 in their next-to-top gear.

Having driven true 3-speed trannies before (column shift even), it is common to feel like you are "missing" a gear for in-town driving. Toyota's swap in 1974 to the 4-speed in the Land Cruisers was done to address this, allowing in-town driving in 3rd and on-road driving in 4th (4th= non-OD 1:1). It also allows you more gears for towing, helping keep the engine in it's powerband, and in it's performance band.

The NV4500 from GM was effectively a 4-speed OD with the addition of a granny gear, giving it all 5-speeds. Having driven a SM465 3-speed + granny trans (G-1-2-3), granny is effectively worthless for on-road use.

The 4.71 1st in the Tacoma is nice, but far from a true 6:5 or 7:1 granny like the older GM stuff.
 

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Discussion Starter #6
Gnzo said:
Scribble,

You are correct on both accounts. The 6th gear can allow for better fuel economy as well as allowing for lower gears. As in the case with the 2005 Tacoma, Toyota opted for the lower gears rather than the better fuel economy. However "Better" in this sense is relative because the 6th gear allows the 05 Tacoma to maintain the same fuel economy as its older brother the 95-04 Tacoma.

Here is an example without getting into exact gear ratios and tire sizes: For my 94 Toyota Truck, 5th gear at 3200 rpm maintains 70mph. The 95-04 Tacoma in 5th gear at 70mph is moving along at 2600 rpm. Now the 05 Tacoma in 5th gear is much like my 94. At 70 mph in 5th gear you are close to 3100 rpm, but pop it into 6th and you drop to 2600 rpm. With the 05 Tacoma, Toyota was able to give us back our closer gearing that we long time Toyota truck owners had grown accustom to. Adding the 6 speed allowed Toyota to accomplish this without compromising fuel economy.

We can only speculate the gearing in the FJC will be similar to the new Tacoma (if not just a little smaller).
Thank you Gnzo,

I appreciate the detailed explanation. I figured I was on the right track but I wasn't sure if I was missing anything. I like the option of 6 forward gears. The kid in me thinks its just down right cool but beyond that I can really appreciate the smaller 1st gear as I own a 94 Wrangler. I've always thought first gear was way too big. When in 4 high you really notice the loss of torque. - Thanks again.
 
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