Rear struts leaking

This is the strut.
In may opinion you can drive it for another ten years and let it leak, as long as it is not broken and you do not carry a load in the rear it should be okay.

You need to start a new question specific to your vehicle, and please be sure to list the engine size and transmission type. This post was a private conversation between two people and they are the only two who will get an automated e-mail message that you added to it. None of the other experts will see your addition or have the chance to reply. That will not get you the help you need.

Not many trucks use struts in the rear. Regardless, if you are expecting to replace rear struts or shock absorbers to cure a tire rub, you are going to be disappointed. Shock absorbers only reduce the vehicle's tendency to keep on bouncing after hitting a bump. They never hold the vehicle's weight up. Struts do the same but they are also structural, and hold the wheel upright. Neither of them affects ride height. That is the job of the springs. McPherson struts have the coil springs around them, but they do not get replaced during the typical strut service you described. The old, sagged springs are removed, then reinstalled on the new struts, so if your ride height was too low before, it will be again.

Removing coil springs has a degree of danger involved because they will be under heavy compression in a tool that can let them squirt out. Extra time is needed too. The cost you listed seems a little high, but it could be right for parts and labor doing the job this way.

"Quick Struts" are available for most vehicles today. Those come as a complete assembly with new coil springs, jounce bumpers, and upper mounts already assembled and ready to bolt in. No strut compressor is needed so the safety issue is eliminated. It is the new springs though, not the struts, that get the ride height back up to where it should be. If you want to check that first, every shop has a small book that lists every year and model, where to take the measurements, and what they should be.

You did not list any details about your vehicle so I do not know if the rear suspension can be aligned and how the adjustments are made. With some designs, the adjustments can slip and cause a wheel to tip out too far on top. That can cause a tire rub totally unrelated to ride height.

Here is a link to an article about replacing shock absorbers:

https://www.2carpros.com/articles/replace-shock-absorber

It is not practical to write an article about replacing struts because they are not exactly do-it-yourself jobs, and there is way too many variations of designs, attaching methods, and procedural steps involved, to cover all vehicles. Replacing shock absorbers rarely requires the vehicle be aligned afterward. An alignment is necessary after replacing struts on the majority of vehicles.