I thoiugh you had 3.55 gears.. In you last post you've typed 4;54's ..
I expect you do have 3:54's .. Those were normal..
You've got one of the best truck out there .. Be careful as to what you do to your truck.. & If you do change the rear axle I'd say save you old REAR AXLE BECAUSE YOU MAY WANT TO REINSTALL it after you find you don't like your changes. & You know yoiu old one is good.
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.......... I've never seen a fuel pump increase fuel mileage any.. So If you got your truck to 22 mpg.. Give yourself a big pat on the back. I've just installed a new rebuilt injection pump on mine. Because mine has alway gotten ''what i call terrible fuel mileage'' for a 2000 24valve. Mine get's maybe 14.5 on a good day.. & AFTER THE NEW injection pump . 3rd on by the way, I installed 6 new BOSCH INJECTORS ... THE MAN that owned the Injection house I'd don't business with for 40 years .. For my Farm & tractors & my Automotive store, I sent my pumps to him for him to rebuild .. But he recommended new injectors. I truly didn't expect them to help at all.. As we never replaced a set of injectors at the Stealership.. only the bad ones.. I even went back to one of the main 2 Diesel techs. No. 2 HAS PASSED AWAY. So I could ask him how he felt about replacing the set of injectors.. He was like me we never did that. But a new set since your man is giving them to you at his cost. can't hurt anything. Nothing changed at all. I'm still at 14.5 .. I've owned my truck since 2004 & this is what it's alway gotten .. The absolute best I've ever gotten was 18.9 FILLED UP & jumped on freeway flat run empty. & i DROVE ABOUT 300 miles cruise set @ about 75mph & Got off & filled again before I started a different section of my trip.. Winding road & up & down different mph & I got about 15 2nd trip. ALL Figured with the calculator. Not from the overhead. .
My truck doesn't get decent /good mileage. AS I Worked at the dealership I ask everyone what their truck go for mileage. Everyone told me theirs got from 16.5 to 22.5.. not mine . AS I said I worked there for about 10 years & We were the largest diesel truck dealer ship diesel shop in Texas.. DESPITE what Lame thinks .. my Noisy diesel get BAD MILEAGE.
........ But be careful with some changes .. Yes I now have a chip on my truck. Funny only thing I think mine does is I think it made mine Noisier. I can't tell it changes anything. Mine had a setting for 25hp 50hp 100hp more. & Fuel economy or one for pulling. I've never noticed any difference. That tech that passed away He swore by this one & He pulled it off his Truck & installed it on mine .. Just before he sold his truck as he knew he had cancer, & would not be with us much longer. SO i PAID HIM & shock his hand & told him thank you.
....... I'd sure be interested in any things you've done to your truck .. those that have helped & Those that haven't helped.
You mentioned buying a trailer . I'm going to say The size of the trailer will determine a lot... My truck 50 % of the time is hooked to a 18ft car/ tractor hauling trailer.. With either a samll 841 Ford tractor on it, or My 72 Bronco wt. about 6000lb. Because of the Cummins 4BT in it & all the wt. i keep in it. Or i also pull an 18ft cattle trailer with 2 or 3 cows in it. Or I have a 32ft flat bed with a Pick-up camper extended over the neck of the gooseneck & THEN some Bronco or tractor going to place in New Mexico It's a 555 mile trip one way. My truck gets 9 to 11 mpg going out there & 11 to 12.5 or 13 coming home down hill. Been doing it for 25 years now. 1st trips were with an old 1990 12 Valve .. On the floor all the way. app 65 to maybe 72 a few miles .. It didn't have an O/D trans. When I got the 24V WE Felt like it had twice the power. While i Still Love my old truck I wish it could get better mileage.
