[travelin texans]

I wouldn't wait 15k miles, my plastic bushings were toast at 5000, at which time I installed the MorRyde heavy shackles/wet bolt kit with all bronze bushings, now have close to 60k miles & no problems.
In my opinion on these heavy 5ers I prefer the bronze bushings with some grease over the Never Fail, to me they are plastic bushings, maybe tougher, but plastic & no grease recommended.