gregamuffin

how much lower would my rpms be if i got 3.55s instead? just curious so i can see if it would be worth it at all, and really, thanks for all your answers sometimes i feel like my questions get ignored...

AdderMk2

~250 rpms.. and the reason we ignore your questions... is because we have answered them THOUSANDS of times...

something like this... a gear speed calculator would have worked wonders for you

http://www.google.com/#hl=en&q=gear+...6c7832dbb01be6

gregamuffin

ill try searching harder next time... everyone else, thanks

nitrous_bob

don't swap out the gears you will hate it... 4.10 is perfect, you'll drop about 250 rpms for every gearset you drop... so 4.10 to 3.55 will knock you down from 3k at 75 to 2500 at 75..... not even noticible for mpg... maybe 1-2 mpg TOPS. but performance will suffer greatly

my buddy went 3.73 in his notch and i did 4.10 in my first notch

they were both all stock w/ et streets and exhaust... i went 13.60's and he went 14.20's

traded cars to check driver error... pretty much the same thing, i got his down to 14.00 and the car still bogged a bit due to lack of gear, he drove mine about 13.80 and no bog.

swapping a single gearset (3.73 to 4.10) is almost pointless..... the only few times i would EVER consider was to go down numerically if i got a blower (4.10 to 3.73) or up numerically cuz the previous owner didn't know what they were doing or were afraid to go fast (3.73 to 4.10)

unless you make 350 or more REAL hp... your car will be slow with 3.55 or lower numbered gears and is sure to bog if you use a sticky tire.

and FYI, 4.10's on a stock 5-speed can lift the front tire on a 5k launch... can't do that w/ any lower numbered gear not even in an earthquake

the good thing about the 1990 t5 is it has a 7 tooth drive gear... so you can correct the speedo for the 4.10's w/ a new driven gear but have to use the white jeep gear. it will wear out but you will be 100% accurate. the newer t5's and all aod's use a 8t drive gear, and all you can correct to is either 3.27 w/ a ford part or 3.55 with the jeep gear.

more FYI, t5's have a removable drive gear and aod's have a drive gear machined on the output shaft and it is not fixable. t5's the best way to correct is use 6 tooth drive gear(black) then use a 20 tooth driven for 4.10's but the trans needs to be disassembled to swap it out. anytime you rebuild the trans though... spend the $15 for the black drive gear.. it just clips on the output shaft and will allow you to correct to 4.30's w/ ford parts and 4.56 w/ jeep driven gear