My truck is in the shop right now, and when it comes back to me, it'll have
a brand new set of 4.10 gears stuffed into its axles, and a beautiful new
paint job. I can't wait to see it!
Anyway... My truck has the 4.3L vortec right now, and 33x12.5 tires,
standard cab, long bed. Does anyone else have a truck similar to mine with
4.10 gears? Are you happy with the way it drives (it was a dog with the
3.08's in there)? Is there ever a chance that my truck will seem "peppy"
with the little V6 pushing it down the road?
You will have plenty of off-the-line pull/pep. Your gas mileage is
another issue. Your vehicle will suck gasoline at an enormous rate, with a
4.10 ratio. On the other hand you could pull the Loch Ness Monster out of
the lake with that gear.
If you run that truck down the highway with a 4.10 ratio, you will learn
very quickly about fuel economy.
It can't be much worse than the 3.08's that were there. With 33" tires, I
had to bury the gas to get it moving, and I couldn't use OD because the
transmission couldn't pick a gear. Engine RPM was way too low even at 60-65
MPH on the freeway. It did the torque converter shuffle and the 4-3 shuffle
constantly. Who knows, I might even get better fuel economy with 4.10's in
OD than with 3.08's in 3rd gear!
You might be right about better mileage with 33" tires. I missed that
in your original post.
Yes, you need more torque to get those big tires moving. The over-all
mileage will increase at a cruising speed, with a 4.10 ratio. On the other
hand, you should really have a V8 in that truck for best performance. A V8
will provide more torque at a lower RPM.
Usually yes... but in this case, there is another variable outside of the
I don't use overdrive with the 3.08 gears.
I ran a calculator online... at 65 miles per hour... The engine spins
faster in 3rd gear with 3.08's than it will in OD with 4.10's. I'm thinking
my milage will improve some simply because I'll be able to finally use
There is roughly a 33% difference between the 3.08's and 4.10's, or a 33%
difference in driveline speed between the two. If you weren't using OD
before and left it in third, you had a 1:1 ratio in that gear assuming the
TC was locking. OD is 0.70:1, so you'll be reducing your driveline speed by
30%, but you have a 33% increase due to the lower gears, leaving you with a
3% surplus. So, you'll likely have the same MPG figure you did before with
some more zip off the line.
Ya know what's really funny? For what you're paying for the ring and pinion
plus installation you could have grabbed a junked 350 and rebuilt it to
around 350hp, which would have given you way more oomph off the line than a
gear change. Just cause you have lower gears doesn't mean your engine
produces more torque! Running 33's with a 4.3 and expecting it to be
"zippy" just ain't gunna happen, regarless of rear end ratio.
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