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1994 Chevy gear change

Howdy, 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?

-NW

Reply to
NetWeasel
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Weasel,

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.

GMdude

Reply to
GMdude

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!

-NW

Reply to
NetWeasel

Weasel,

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.

GMdude

Reply to
GMdude

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.

Doc

Reply to
"Doc"

Inline..................

Wrong. Higher gear ratio = higher RPM = more fuel being used.

Overall mileage will increase when changing from 3.08 gears to 4.10's? You must be smoking the same stuff Marsh Monster is!

Doc

Reply to
"Doc"

Usually yes... but in this case, there is another variable outside of the axle ratio.

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 overdrive.

What'dya think?

-NW

Reply to
NetWeasel

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.

Doc

Reply to
"Doc"

Cool. That I can handle! Thanks!

-NW

Reply to
NetWeasel

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