I need help finding out what gear ratio my front end has I have a 01 grand Cherokee and need to replace front end
Unless you're the original owner the only 100% positive way to find out is to remove the diff cover. 99% of the time pulling a factory build sheet will be fine. You can also jack up the front or rear and rotate the driveshaft and see how many rotations compared to the tires on that axle. Stock gear ratios are 3.55's and 3.73's. Since those ratios are close it might be kind off difficult to see the difference between 3.55 and 3.73 rotations unless you're paying close attention.
All V8's received 3.73 gears, regardless of being equipped with the factory tow package.
I6 motors will have 3.55's if they do not have the factory tow package.
In the previous generation, the ZJ with an I6 and the tow-prep package came with 3.73 gearing. So you might check to see if that's listed on your build sheet. If it's got an I6 without either the tow-prep package or the tow package, then it will default to 3.55. This is if the rules for the ZJ apply to WJ's.