Gear Ratios

sam3 · December 22, 2004

Can someone please tell me of the pros and cons of a bigger gear ratio versus a smaller gear ratio in the back. Thanks.

vhato · December 22, 2004

Can someone please tell me of the pros and cons of a bigger gear ratio versus a smaller gear ratio in the back. Thanks.

<{POST_SNAPBACK}>

A ratio like 4.10:1 is considered Low. Low ratios in the rear axle place the truck load on the axle. It allows the engine and transmission to not work as hard.

Benefits:

1. Engine and Transmission don't work hard (no strain)

2. Trucks Accelerates FASTER from at Low speeds (-35 MPH)

Negatives:

1. Possibly LESS gas mileage

2. Truck Accelerates Slower at Higher Speeds. (+55MPH)

A ratio like 3.42:1 is considered High. High ratios place the load of the truck on the engine and transmission. The Engine and Transmission must work HARDER to move the truck from a dead stop.

Benefits:

1. Possbile Increase in Gas Mileage

2. Truck Accelerates FASTER at Higher Speeds (+55MPH)

Negative:

1. Engine and Transmission Work Harder (May Increase Possibility of Transmission Failure if larger than stock tires are added)

2. Truck Accelerates SLOWER at Low Speeds (-35MPH)

My Points will probably be argued by people with 35" tires with 3.73 or less gearing.

Chris97K1500 · December 22, 2004

I'd agree with vhato, I'd only add that the mileage thing could be better with lower (4.10) gearing if you drive mostly in traffic, stop and go. But if you drive mostly highway, the higher (3.42's) would give best mileage. Lot of it depends on your driving habits. I've got 4.56's with my 35's and it's night and day different from the 4.10's I had, couldn't imagine any less gearing than 4.10's with 35's or bigger, lots of power loss! Chris

sam3 · December 22, 2004

so from that vhato, if I just wanted freeway merging performance, 3.55 would be okay and if I wanted better stoplight performance I'd want to go with 3.73?

vhato · December 22, 2004

so from that vhato, if I just wanted freeway merging performance, 3.55 would be okay and if I wanted better stoplight performance I'd want to go with 3.73?

<{POST_SNAPBACK}>

Even though there isn't a noticeable difference between 3.55 and 3.73...You now have an understanding of the difference. Glad I could help.

sam3 · December 23, 2004

thanks vhato. I am getting an 05 F-150 in a few days and it came with a 3.55 limited slip. I am still keeping my silverado so I'm not a complete traitor. Just wanted to make sure the 3.55 was adequate performance wise.

Nice truck vhato, I'm going to have to pick up a set of cab-roof lights now!

vhato · December 23, 2004

thanks vhato. I am getting an 05 F-150 in a few days and it came with a 3.55 limited slip. I am still keeping my silverado so I'm not a complete traitor. Just wanted to make sure the 3.55 was adequate performance wise.

Nice truck vhato, I'm going to have to pick up a set of cab-roof lights now!

<{POST_SNAPBACK}>

Wow,

An '04 HD w/Dmax/Alli Combo and an '05 F-150. I am impressed.

On the Ford's 05 F-150 they are using the 4R70E Transmission. That 2.84:1 first gear is similar to GM 4L80-E which is found in HD and 2500LD trucks w/6.0 Engines. What this means to you is smooth, strong, precise shifts on the good side. The bad side is less than desireable 1st acceleration with high (3.55:1) rear axle ratio's. I drove a new Ford F-150 w/the new 300 HP/365 lbft Triton 5.4. It had the automatic and 3.55 gears. I was less than satisfied. The truck moved so slowly from a dead stop and at low speeds that it felt like I was towing a trailer. "I" wouldn't choose that axle ratio. If this were the wifes truck I would get 3.73's (because I would drive it sometimes) and if it was for me I would get 4.10's. The Low .70:1 Overdrive ratio will provide nice fuel economy with whatever rear axle choice you make.

Thanks for the compliment on the Cab Lights. When I ordered the truck I was nervous because this was my first 3/4 ton and m first w/Cab Lights. I love them. Every 2nd trucks wash I break out the Plastic Wax and shine up the Cab Lights, Tail Lights and other lights so they are nice and shiney. Plastic Wax REALLY brings out the shine in 03-05 trucks. I recommend everyone try it, you will see a difference.

sam3 · December 23, 2004

air intake, exhaust and a tuner will be my first mods

lesmore49 · December 24, 2004

Iagree with the comment on the benefits of high/low gears. I used to run a TH350 hydramatic with a 350 chevy small block V8. I don't know what the rear end ratio was but I think, as this was a 70s vehicle, prob. around a 3:08. It was OK.

Now my chevy has a 3:42 with a 4L60E. I ordered it with the 3:42 rather than the 3:73 because at the time, even though the 4L60E has an overdrive I was thinking it would rev too high at highway speeds with the 3:73s. When I ordered it my mind frame was thinking 3 spd auto rather than 4 spd. I did'nt think about the overdrive compensating for the 3.73s.

Although the 3:42 is ok if I was ordering again I would go with 3:73s or maybe 4:10s if I was towing a heavier trailer.

What I would like to see, in the near future is a GM auto (not counting an Allison) with 5 or maybe 6 speeds to replace the 4L60E and 4L80E. I believe some of the new light truck (Nissan?) have 5 speed autos have a 3:83 first gear in the tranny, compared to a 3.06 first gear in the 4L60E.

Benefits? Wider range of internal gears and you can have acceleration and economy. Anybody know if GM will come out with 5 or 6 spd autos for their light truck line in the near future?

vhato · December 24, 2004

6-speed auto (4-Forward/2-Overdrive) will be in the redesigned trucks due summer '06.

Mark_in_Tulsa · December 24, 2004

6-speed auto (4-Forward/2-Overdrive) will be in the redesigned trucks due summer '06.

<{POST_SNAPBACK}>

Thats awesome My Hemi Ram has a 5 speed auto, 3 forward, and 2 overdrives.

3 is 1: 1

4 is 1: .73ish

5 is 1: .63ish

Something like that.

But a 6 speed would be awesome.

vhato · December 24, 2004

6-speed auto (4-Forward/2-Overdrive) will be in the redesigned trucks due summer '06.

<{POST_SNAPBACK}>

Thats awesome My Hemi Ram has a 5 speed auto, 3 forward, and 2 overdrives.

3 is 1: 1

4 is 1: .73ish

5 is 1: .63ish

Something like that.

But a 6 speed would be awesome.

<{POST_SNAPBACK}>

And I think the Dodge SOMEWAY has two different 2nd gears. One for 1st-2nd upshifts and another for downshifts into 2nd. I remember the ratios were different because they combined one of the OD's.

Mark_in_Tulsa · December 24, 2004

6-speed auto (4-Forward/2-Overdrive) will be in the redesigned trucks due summer '06.

<{POST_SNAPBACK}>

Thats awesome My Hemi Ram has a 5 speed auto, 3 forward, and 2 overdrives.

3 is 1: 1

4 is 1: .73ish

5 is 1: .63ish

Something like that.

But a 6 speed would be awesome.

<{POST_SNAPBACK}>

And I think the Dodge SOMEWAY has two different 2nd gears. One for 1st-2nd upshifts and another for downshifts into 2nd. I remember the ratios were different because they combined one of the OD's.

<{POST_SNAPBACK}>

Your right I totally forgot about that, and I forget how they do it.

But so far this new tranny has been great for them.

But of course anything would of been an improvment over their last one.