I have 100k miles on my truck and decided to upgrade my 2018, 2.7 Lariat, 4wd with Billstein 5100 shocks and struts. My plan was to just have them switch over the existing coils to the new struts. However, I can get a set of struts taken off of a 2020, 4wd, 2.7 at 4,000 miles and I was thinking about using those springs instead of mine. However, the part numbers don't match up on the struts or coils.
my part number on the strut is JL34-18045, theirs is GL34-18045.
my coil is stickered jl34sa theirs is fl342ah.

Does anyone know, is the difference in part numbers due to the different model years? I tried looking it up, I thought it might have something to do with a heavier spring, but I just don't know. Am I just over thinking this? Should I just use my existing springs and be done with it? Or, should I try to update with a newer spring?

Appreciate any help.

 

Those springs will fit. The only difference should be spring rate, which I'd assume would be nearly identical since they're coming from nearly identical trucks. The easy way to know what springs are in each truck is to look at the door jamb sticker. Under 'SPR' there should be a four digit code like BBVV or whatever. B would be your front spring, and V your rear leafs. If both trucks have the same code, the springs should be the same.

 

Is one truck an FX4 and one a regular 4x4? If so, that’s the difference. FX4 came with different front coils.

 

I think this is one of those situations where you might as well keep your old springs. The spring is rarely ever the wear part of the coil over, it's going to be the shock absorber that goes bad. The spring should still be just as effective as brand new.
When you think of cost vs. benefit, I'm going to the say the sight possibility of the ride being even ever so slightly better (or worse for all we know) and possibly having fitment issues does not outweigh the work involved in taking on this experiment.
That's just me though.