FMTV High Speed Gears

[ramdough]

Im curious..... most info I've read was the 3116 got around 6.5-7mpg. Why do you think your's was at first getting half what has been suggested as the norm? Or is my recall of the "norm" way off base?

I have heard the same thing....6.5-7 was stock normal.


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[mkcoen]

I have heard the same thing....6.5-7 was stock normal.

Last long drive I did I was keeping steady at about 55mph and got 6.3mpg. I'm willing to bet if I was going convoy speed at 45mph it would have been closer to 7.

 

[Keith Knight]

I can't explain why mine was originally getting such terrible gas milage besides the obvious high RPM's at 55mph. But with over 2,000 miles on it prior to the gear change and checking it a few different ways, thats what I was getting. It surprised me to, but with no trouble codes or any other obvious cause I just have to accept it.

 

[expeditionnw]

Keith also has an A1 with a C7 cat. Perhaps his economy is due to that. my 3116 sees a bit over 6mpg with factory gears.

 

[sjohn116]

Can anyone advise about the speedo input and recalibration for a WTECII 3116 A0 truck?

 

[scottmandu]

I can't explain why mine was originally getting such terrible gas milage besides the obvious high RPM's at 55mph. But with over 2,000 miles on it prior to the gear change and checking it a few different ways, thats what I was getting. It surprised me to, but with no trouble codes or any other obvious cause I just have to accept it.

That's weird my 1084A1 with the C7 gets 5.8 mpg at approx 60 mph, and it's almost 9000 lbs heavier.

 

[Keith Knight]

Please tell me the secret to better MPG. LOL!

 

[scottmandu]

Please tell me the secret to better MPG. LOL!

IDK I run the MRAP CTIS computer which I believe keep the tires at 100psi, versus the 75.

 

[ramdough]

So what is a typical 1083+ MPG?


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[scottmandu]

So what is a typical 1083+ MPG?


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I'd wager 5-6mpg..

 

[ramdough]

So you lose 1 MPG for the added axle and weight? That does not sound too bad of a trade. Percentage wise it is huge, but by absolute numbers not so bad.


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[Jcbawn]

who makes these gears? is there a make / model? Are there any directions or TMs on this conversion?

 

[scottmandu]

who makes these gears? is there a make / model? Are there any directions or TMs on this conversion?

Meritor part number B416561

 

[1951M1078]

B416561 Is this the 3.07 set ?

 

[scottmandu]

The hub reduction isn't 2:1 it's 1.71:1.

 

[NDT]

The hub reduction isn't 2:1 it's 1.71:1.

This statement is in direct contradiction of the info published in TM9-2320-365-10 section 1-13 equipment data.

 

[scottmandu]

Whoever wrote the book didn't count the teeth.

 

[scottmandu]

24/14 = 1.7143

 

[Suprman]

So would that make the fina drive ratio approx 6.70?

 

[steve6x6x6]

The hub reduction isn't 2:1 it's 1.71:1.

Where do you get this info.? The chunk is marked 3.07 and the housing is marked 6.14 finial drive.