A/T P tires in front, Highway LT's in back, any problem?

Does your owner’s booklet address this issue?

https://www.fordservicecontent.com/Ford_Content/catalog/owner_guides/02hdwog4e.pdf

Page 252 says “no” twice. Page 253 says it two more times.

As long as they are the same circumference. there should be no problem.. The problems come in when all tires aren't the same size

THanks, that's what i thought. i figure i'll buy the other two by the time i'm due t rotate them.

Different tires have different characteristics of handling properties.
One caution I can offer is to check that out.
Example if one tire has a much more flexible sidewall that the other, it could cause it to handle differently than you are used to.

But basically should be ok.

Since we are not driving high performance cars at LeMans, I'd think you are okay.

think of wearing different brand/size/type/etc shoes. Tennis shoes to hiking boots

Walking around the house would be fine...but...then try running as fast as you can to then 'maneuver' around things.

Those difference will affect during extreme conditions. Like braking & swerving trying to avoid something.

I'd not do it

Stability will be effected. I am betting the Tire store has a credit offer of some sort. Do it right.

Does nobody remember "snow tires"? Back in the day most people, on most vehicles, ran rear tires that did not match the front for about half the year.
(On my pickups, snow tires in winter, then spring I would name them "Mud Grips")
As for different size F/R. 2 wheel drive, this is not a issue. 4 Wheel drive, can be a problem unless on surfaces you need 4 WD, and tires can slip

I currently have LT all terrains on the back. and a matching set (Firestone Destination) but the fronts are P.
So,i assume the rears are stiffer. It handles like a 4 ton truck.

I'm thinking
replacing the rear with highway tread Michelins will have the same stiffness but better grip on asphalt.