with my 2002 jeep grand cherokee loredo…is it saving me gas to drive in overdrive all the time?

If you have the MPG meter in the cab, you can find out for yourself. Watch MPG at 50 MPH and OD off. Engage OD, watch the engine rpm drop 25% and a corresponding increase in gas mileage.
Else..take my word for it. The slower you can keep that engine, the less fuel you will use. The system will automatically shift out of OD when you need it.
Good Luck

Yes. Overdrive lowers the overall gear ratio so the engine sits at a lower RPM. Obviously, if your car is at a higher RPM then its burning up more gas. There’s not really any sense in not driving in overdrive, unless you don’t exceed 30 miles an hour. Basically, it’s like if you were going 25 miles an hour and just decided to keep it in first gear the whole time – it’s just going to waste gas & wear your engine out quicker.

Keep it in overdrive unless you’re towing something. In that case, do not put it in overdrive as that’ll put more stress on your transmission. And drive emits more torque than overdrive.

So yes, it is saving you gas.

no dont do that if u do it to much it may blow the transmition

Yes, if you drop it out of OD, your mileage will suffer. Watch the in cab display and see for yourself. You didn’t mention if you had a V8 or L6, in either case, don’t do any hard excellerations and that alone will help with your mileage.

Unless you are in hill country, or stop and go city driving-leave it in Overdrive-that’s what the manual will tell you. As others pointed out already, it will ‘automatically’ drop engine speed to save you maximum gas efficiency WITHOUT hurting the transmission one bit. If you are towing, or in very hilly terrain and you notice it really winding up to shift too often-then drop out of it. Otherwise, leave it in OD.
If you have to engage the 4wd, also shift out of it…. because you shouldn’t be in 4wd at high speed.

YES. That allows the engine to turn slower.
If you come to a hill with the cruise control on and the engine begins to pull a bit too hard the transmission will drop down a gear and ease the workload of the engine. On real hilly roads, I turn off the cruise so the trans is not shifting excessively. But in normal driving I like to use the overdrive as much as possible.