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Old 08-24-2014, 12:39 PM   #1
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Will regearing save my mpgs

Currently I'm running 3.07 with 31 in tires would going from a 3.07 to a 3.73 boost my mpgs from 12??

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Old 08-24-2014, 01:49 PM   #2
Knows a couple things...

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Not enough to warrant the cost of regearing. But yes it could raise your mpg a tad but more importantly, regearing to a more appropriate lower gear ratio would remove the doggy performance caused by the terrible 3.07 gearing. The right gear ratio would raise your smile factor immeasurably.

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Old 08-24-2014, 02:26 PM   #3
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I get about 13-14 tops and that was before and after the regear. These engines are good for low end torque but a pig on gas no matter what. Just like chevy's 4.3. Another great engine but very poor fuel economy.
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Old 08-24-2014, 04:57 PM   #4
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I had 3.07 with 31 and full gas tank can only run for 170 miles top. I did the regear last week. Now I have 4.56 with 33 and it run around 210 miles with full tank of gas.
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Old 08-24-2014, 05:26 PM   #5
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As far as I know I have 3.07s with 33"s and it's not too fun. Probably get around 9 mpg and 160 miles per tank with a 15 gallon tank
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Old 08-25-2014, 12:37 AM   #6
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I recently found out my 97 2.5 has 4.10s from the factory. I was excited to learn that I didn't have anything in the 3s... I was disappointed to know that even with 4.10s and 31s... It's still gutless as hell. I can't imagine what 3.07s would be like.
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Old 08-25-2014, 12:42 AM   #7
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Will regearing save my mpgs

No, but buying a fuel efficient vehicle will.
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Old 08-25-2014, 05:15 AM   #8
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I have a 05 sport with stock 373 gearing running 33x12.5 mud tires. Going 60 mph I get 19mpg. I have a 4" lift, winch ect.. Don't know if mine is an odd one, but I get good mileage.. I am going to 488's soon tho..
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Old 08-25-2014, 05:30 AM   #9
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dumb question but how do I tell what gears I have?
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Old 08-25-2014, 08:17 AM   #10
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dumb question but how do I tell what gears I have?
Look for a tag @ 9°clock position with ratio stamped in lower left of tag
Pull cover and look for the numbers stamped on the edge of the ring gear and divide
Jack up and spin the wheel and count driveshaft revolutions....
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Old 08-25-2014, 09:26 AM   #11
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dumb question but how do I tell what gears I have?
This one is a 3.73. You should have a similar tag on your differential (if it hasn't been regeared).
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Old 08-25-2014, 09:32 AM   #12
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Probably get around 9 mpg and 160 miles per tank with a 15 gallon tank
math?
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Old 08-25-2014, 10:57 AM   #13
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I have a 05 sport with stock 373 gearing running 33x12.5 mud tires. Going 60 mph I get 19mpg. I have a 4" lift, winch ect.. Don't know if mine is an odd one, but I get good mileage.. I am going to 488's soon tho..
Unless you put in a new speedo gear your mpg/mph are not going to be accurate.
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Old 08-25-2014, 02:28 PM   #14
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math?
lol
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Old 08-25-2014, 08:38 PM   #15
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lol
eh it was a assumption, I give up. It's a jeep. Who cares what ya get. Just have fun. It's a brick on wheels.
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Old 08-25-2014, 09:29 PM   #16
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Other things can help for increasing mpg, i was getting 11mpg with 33 tires with 3.73 at first after the tire upgrade(saving up for axles and gears). I reset my ecu(so it would start over learning my driving habit), I turn off my Auto overdrive(run about 2500rpm at 65 highway), cause with the low gears, any incline would slow the jeep down and the negine had to work more. I started to use cruise control, changed injectors to Bosch 4-hole design.
After changing the injectors, the engine smoothed out so nicely, it now had a problem staying running it was so smooth. That lead to me finding that my IAC was bad and filthy in the throttle body(replaced & cleaned), guess the old injectors had extra unburnt fuel, it kept it idling and then added new plugs.
After all that i get about 13.75-14.25 mpg now and that is with about 10min idle run time also each day. It small, but still better then 11.
Hopefully when i get the axles and gears, being able to use my overdrive i can keep it about the same or a little bit extra.

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