locked up

98k1500 · 02-21-2008, 07:37 PM

alright, check this out, i was thinking maybe i need to invest in some, shorter gears in the rear, in the process i would have to remove the third member, i have posi but why not a locker, maybe say automatic, any ideas, how much is say a 3.23 ring and pinion gonna set me back? any body have anything close to that?

75K30 · 02-21-2008, 09:45 PM

What gear ratio are you running now, and why the desire for a 3.23:1 ratio?
That seems like a very tall gear for a 4x4 truck. Why not at least a 3.73 or even 4.11?
Assuning that this is for your "K" truck, you will need to swap gears for the front and rear.

98k1500 · 02-22-2008, 07:27 PM

yeah ive got 3.73's and i dont get **** for mpg, figured some "taller" gears would get a little better... check out the "mpg SUCKS" thread... not a good idea? if you read the other thread and understand my problem, can you give me a better option that i could try? i just cant think of anything else.

75K30 · 02-22-2008, 09:22 PM

Well here is the thing. MAybe I replied n the other thread. If you have a heavy truck and you believe that you will get better mileage by going to a numerically lower gear, then you might want to re-consider.
Take a dew factors into consideration. One factor would be how often you are actually at highway speeds in overdrive on flat ground. Chances are not very often. The amount of additional effort the engine has to produce to get the heavy truck going, and keep it going usually offsets any milage gains by decreasing engine rpm at crusie speed.
Second factor would be how much towing or hauling you do. This is important because just like the trucks drivetrain having to work harder to get the truck going while empty, it has to work even more to get a load motivated. Most of the time you will be way below the optimum torque band of the engine and the thing wii actually get worse mileage.
Third factor could be argued but I will throw it out there and that would be the additional wear on the drivetrain,especially the transmission.
Remember trying to take off from a stop light, or climb a hill on an old ten speed bike when in the wrong gear? Pretty hard on the legs huh? Same is true for your engine and transmission. Will be like trying to take off in second gear all of the time. Can it be done, yes, but is it counter productive? Again I believe yes.
I am a fan of running a sick amount of gear in any vehicle. 4.10:1 with stock sized tires would be about the least gear I would ever consider. Believe it or not, when the engine is running efficiently it can get pretty geed mileage even at higer rpm's. It will have a machanical advantage over resistance with a lower ratio (numerically higher) and has the potential to get better mileage.
I feel you might be chasing your tail here and would spend way too much money and never see a return on your investment. Fact, this would probably be a poor investment. I believe you could obtain better mileage by trying other things to make the engine get a little better mileage.
I run 5.13's in a Tahoe woth 39" tires and have gotten as good a 14 mpg. Could not imagine trying to get my beast rolling with anything different than this. I have also considered 5.38's.

Other options could be just a driving style change. Good and proper tune is a must, and checking the little things. Tire pressure, rolling resistance, bearings, alignment etc.

98k1500 · 02-23-2008, 03:56 PM

well, i dont ever pull anything right now, most of my driving is on the open FLAT kansas highway and i have a really light truck, i am thinking of getting new rolling stock soon... i run the stock size tire, but i have aftermarket rims...am really just looking at getting better mileage out of my truck... thanks

02-21-2008, 07:37 PM	#1
98k1500 Senior Member Join Date: Jan 2008 Location: Kansas Posts: 82	locked up alright, check this out, i was thinking maybe i need to invest in some, shorter gears in the rear, in the process i would have to remove the third member, i have posi but why not a locker, maybe say automatic, any ideas, how much is say a 3.23 ring and pinion gonna set me back? any body have anything close to that?

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02-21-2008, 09:45 PM	#2
75K30 Senior Member Join Date: Jul 2006 Posts: 2,627	What gear ratio are you running now, and why the desire for a 3.23:1 ratio? That seems like a very tall gear for a 4x4 truck. Why not at least a 3.73 or even 4.11? Assuning that this is for your "K" truck, you will need to swap gears for the front and rear.

02-22-2008, 07:27 PM	#3
98k1500 Senior Member Join Date: Jan 2008 Location: Kansas Posts: 82	yeah ive got 3.73's and i dont get **** for mpg, figured some "taller" gears would get a little better... check out the "mpg SUCKS" thread... not a good idea? if you read the other thread and understand my problem, can you give me a better option that i could try? i just cant think of anything else.

02-22-2008, 09:22 PM	#4
75K30 Senior Member Join Date: Jul 2006 Posts: 2,627	Well here is the thing. MAybe I replied n the other thread. If you have a heavy truck and you believe that you will get better mileage by going to a numerically lower gear, then you might want to re-consider. Take a dew factors into consideration. One factor would be how often you are actually at highway speeds in overdrive on flat ground. Chances are not very often. The amount of additional effort the engine has to produce to get the heavy truck going, and keep it going usually offsets any milage gains by decreasing engine rpm at crusie speed. Second factor would be how much towing or hauling you do. This is important because just like the trucks drivetrain having to work harder to get the truck going while empty, it has to work even more to get a load motivated. Most of the time you will be way below the optimum torque band of the engine and the thing wii actually get worse mileage. Third factor could be argued but I will throw it out there and that would be the additional wear on the drivetrain,especially the transmission. Remember trying to take off from a stop light, or climb a hill on an old ten speed bike when in the wrong gear? Pretty hard on the legs huh? Same is true for your engine and transmission. Will be like trying to take off in second gear all of the time. Can it be done, yes, but is it counter productive? Again I believe yes. I am a fan of running a sick amount of gear in any vehicle. 4.10:1 with stock sized tires would be about the least gear I would ever consider. Believe it or not, when the engine is running efficiently it can get pretty geed mileage even at higer rpm's. It will have a machanical advantage over resistance with a lower ratio (numerically higher) and has the potential to get better mileage. I feel you might be chasing your tail here and would spend way too much money and never see a return on your investment. Fact, this would probably be a poor investment. I believe you could obtain better mileage by trying other things to make the engine get a little better mileage. I run 5.13's in a Tahoe woth 39" tires and have gotten as good a 14 mpg. Could not imagine trying to get my beast rolling with anything different than this. I have also considered 5.38's. Other options could be just a driving style change. Good and proper tune is a must, and checking the little things. Tire pressure, rolling resistance, bearings, alignment etc.

02-23-2008, 03:56 PM	#5
98k1500 Senior Member Join Date: Jan 2008 Location: Kansas Posts: 82	well, i dont ever pull anything right now, most of my driving is on the open FLAT kansas highway and i have a really light truck, i am thinking of getting new rolling stock soon... i run the stock size tire, but i have aftermarket rims...am really just looking at getting better mileage out of my truck... thanks