Gearing 308 VS 342 What?

[BigBadSierra]

 

 

I still swear that my 2005 Silverado 1500 5.3L with 4.10's felt alot sharper than my 6.0 and 6.2L trucks with 3.73 and then 3.43 rear ends.

Your correct 4:10 that I've had before Snap right into it when you hit the gas.

 

One truck I had with the locker and a 4:10 would take off straight as soon as the locker dis-engaged it would light both back tires up under heavy acceleration. I always had to be careful when the road was wet...

 

That being given the 3:42 and even the 3:73 are a little better for just driving.... But the power with the 4:10 was good for the towing you have to put up with it misbehaving with no load... ha ha.. at least on a 2WD..

[crushNchowda]

 

 

No problems comprehending, it's that the current trucks are tuned like absolute dogs. My 6.2L & 6 speed didn't even wake up until I threw on headers and got a dyno tune. My 5.3L truck was alot better out of the box.

No and I get that too - like I said in another thread its the pulled spark & timing, torque mgmt, low shift torque/pressure, shift points, A/F mixture etc etc that all contribute to what some view as lackluster performance. A tune changes it night & day - you don't need headers either, tune alone will do wonders particularly for the trucks - see the performance vehicles that share the engine/tranny (or one of the 2) w/ the trucks have higher thresholds for performance potential & they're also not built to tow/haul stuff - so I think GM neuters the programming even more so on the trucks not just for gas mileage but also to help preserve drivetrain components should the truck be used hardcore as a workhorse like a fleet vehicle AND to prevent guys who are used to driving 200 HP dogs from quite literally killing themselves.

 

You tune a 6.2 & throw intake/headers on it you're essentially driving the equivalent of the old SRT-10 Rams power-wise.....more than enough to wind up in a ditch quite easily lol!

[dorkweed]

Engine size is often how we tend to measure our vehicles. Gear ratios, transmissions, and even wheel size play critical roles on the final outputs of our trucks. I just read that the 1985 Ford CC with 150 hp was rared to pull 12,500 lbs.! My 105 hp engine of the day handled very substantial loads as well. It is not totally accurate to compare vehicles by one or two parts of the powertrain.

 

 

IMHO; the best engine that Ford ever produced was the old 300cid I-6. Put the "3 on the tree" manual behind that, and you had a pulling machine.....................just wasn't very fast!!!

[Donstar]

 

 

IMHO; the best engine that Ford ever produced was the old 300cid I-6. Put the "3 on the tree" manual behind that, and you had a pulling machine.....................just wasn't very fast!!!

I agree. I owned 4 trucks with the 300. One with the 3 spd and three with the 4 spd! In my opinion any more power is simply a bonus. The new 4.3 has two and a half times the horsepower and more power than most will ever need in a 1/2 ton.

[dorkweed]

I agree. I owned 4 trucks with the 300. One with the 3 spd and three with the 4 spd! In my opinion any more power is simply a bonus. The new 4.3 has two and a half times the horsepower and more power than most will ever need in a 1/2 ton.

 

 

 

The problem I see with the "bit chin and moan in" here is that MOST members here didn't grow up towing and hauling things. I grew up driving a tractor, and a pickup around the farm.............torque is where it's at.................hence my prior 2 vehicles before this current Chevy were Dodge/Cummins 2500 pickups.

 

The "modern" diesels are much more "car-like" in their behavior. The old ones were "torque monsters" right off idle...............now it takes an "automatic tranny" and/or major torque management to handle the power the diesels give you because folks didn't like the slow acceleration..................even though you could pull your house off the foundation with the torque!!!

[Cowpie]

Yeah it "felt" quicker but it sure as hell aint.

 

Why is everyone having difficulty understanding that 4.10 gearing with a 4 speed or even a 6 speed is an apples to oranges comparison when you're jumping up to 8 and now 10 speed transmissions?

 

8 speed w/ 3.73 > than 4 or 6 speed w/ 4.10

 

 

But the top gear of either the 6 spd or the 8 spd is virtually the same. The only difference is the steps between gears being a tad shorter with the 8 speed. At the top, no advantage to the 8 speed at all. And the ability to get moving is also a function of the diff ratio as much as it may be with the trans ratio. Only a very deep reduction trans will compensate for a tall diff (lower numeric number). And that is all GM did. Offer a little deeper reduction on the bottom of the 8 spd, along with some shorter ratio spreads, all to compensate for the goofy tall diff ratios they are using now. And then torsional stresses come into play on everything. The taller the diff ratio, the stronger the drive shaft and U-joints have to be to compensate. In other words, something like the 4.10 still wins out when you factor in everything. Unless you are trying to set a new land speed record.

[Bobber]

I'm not sure that an improvement in fuel economy is to be had with the 3.08s over the 3.42s (like others have stated). I thought so initially when I got my 2014 CC 5.3L (and asked for one with 3.08s for that reason). I do a lot of highway driving, and didn't expect to be towing much more than my 500# total weight fishing boat/trailer - (I now have 83k miles since Jan 2014). I hadn't really included the AFM V4/V8 mode impact on fuel economy when I chose the 3.08 ratio.

 

One thing I do notice, there are times when I expect the AFM to transition to V4 mode and it doesn't unless I lighten up just a little on the throttle (which sometimes means maintaining/losing speed rather than increasing/maintaining speed), or wait for the insignificant grade to "flatten out" or "fall off". I think I'm just below a point on the power/torque curves where the computer thinks V4 mode could handle the load so it either doesn't go there, or transitions back to V8 mode sooner.

 

And now, I've recently acquired a 7x16 enclosed trailer for my Polaris Ranger and related gear (trailer has 105" OAH). I definitely "feel" this new trailer in the throttle pedal (even when it is empty) and I'm certain that my mileage suffers when towing (maybe less-so if/when I go "manual mode" on the trans). But, it definitely suffers in pulling/torque demand conditions.

 

I don't drive this like its a drag truck or a sports car... so I don't really care about measured differences in 0-60 or 60-100 times. My truck does fine (for me) when passing at speed, but would probably do even better if it was running higher on the torque band/curve and just needed to jump from V4 to V8 mode instead of dropping a gear too. I have rarely been at Max HP (5600 rpm) - even when towing the 4000# loaded trailer; but I'm sure I've been at Max Torque (4100 RPM) many times with the trailer.

 

There is an age-old saying: "Horsepower Sells, Torque Wins"; or "You buy Horsepower, but you drive Torque"... for more info check out:

http://ateupwithmotor.com/terms-technology-definitions/horsepower-vs-torque/

[GRN69CHV]

I sure as heck don't miss AFM and V-4 mode. Last week I made a 270 mile round trip leaving and coming home at rush hour, including stop/go, low speed highway construction zone as well as maybe 50% highway cruise and averaged 19.9 mpg. Made another shorter trip up I476 yesterday, no traffic either way. 60 mile one way trip on the highway with some rural driving in between. Ran 70 mph on way up, 80-85 on the way back. Truck averaged 22.2 mpg combined, 25 mile avg mpg was over 25 on the way there, 23 something on the way back. A couple times, just to see how it ran, speedo hit the triple digits. It had absolutely no problem pulling 80+ mph without any sign of straining or wanting to downshift, running in 6th gear with 3.08 gearing.

 

Reminded me of running one of our big diesels, high gear at 1800 rpm, settled right into a nice cruise.

 

If/when I replace this truck, it will have preferably have at least 3.42 gears. If I could get aftermarket gear sets to fit the factory carriers, I'd have already swapped out gears for either 3.42's or 3.73's. Personal preference would be 3.73's.

 

Using 70 mph as a reference, with 32" tires, cruise rpm is:

3.08 = 1517 rpm

3.42 = 1684 rpm

3.73 = 1837 rpm

4.10 = 2019 rpm