Ok I know I am probably beating the crap out of a dead horse, and I am sorry for that, but I just need a good straight answer.
I bought my 99 TJ used and it already had a four inch suspension lift and a three inch body lift on 35's. It still has the 373 gears. I am getting about 11mpg. I have always felt like I had a loss of power somewhere.
Can those of you that have gone from the 373 to the 488 on 35's tell me what difference you experienced and if you would advise me to make the change. What type of mpg difference can I possibly expect?
definitely go for it, though you may have other issues causing that low fuel economy. i have 33s on 3.73 and still get 18-20. did you replace your speedometer gear? that would give you an lower number when you calculate it. 35s on 3.73 you also pretty much don't use overdrive... 4.10s are probably bare minumum but 4.88s give it plenty of power and up in the 17+ mpg range
this may help you visualize the situation: try starting off from stop in 2nd gear. think of that as your current setup. regearing would be a lot like starting off in 1st gear.
you would certainly get more power, less wear, and less strain on the engine. with 4.88s you can actually use overdrive any time you're up to speed. the key is your engine uses less effort to move the wheels so as long as its not too out of proportion you will gain power and fuel economy
I havent changed my speedometer gear, I am guesstimating it at 11-12mpg. its actually calculating out to be 10.5. Its my DD and at $3.80 and rising I am starting to stress over my milage. It is starting to slow down my travels in my jeep and we all know that is a BAD thing. I think i also have a small exhaust manifold leak but the exhaust shop swears that I dont...... 17+ is my goal.... i would be happy with that since that is what a typical truck would give me. Thanks for the input