My 2015 Edge manual liftgate is starting to sag. The two struts are different between the left and right sides. One side looks like a conventional lift strut and the other is bulkier and looks more like a suspension shock. I suppose one or the other (hoping not both) need to be replaced but would prefer not to have to guess which one. Any suggestions? It looks like I can get one for about $30 and the other is over $100. I suppose I could buy the cheaper one and see if that fixes it. Some web sites say the cheaper one can be used on either side. Any experience with that? Thanks!

 

Two options for testing.
Find another good vehicle same model/year/trim level and swap one strut from the good vehicle to your vehicle and see if that fixes it, if it does replace that one, if it does not replace the other one.
I suppose you could remove both struts and compress them and see how fast they extend, but you don't have a frame of reference for how fast a good strut extends.
Use something/someone to hold the liftgate up when a strut is removed, the liftgate is rather heavy and you don't want it to slam down on you.

Honestly since its only $30 I would just replace the cheaper one and see if that fixes it.

 

Change them both. Chances are if one is weak, the other can't be far behind. Why risk a potential injury.