I have the 2475 on a ck3510se, so not exactly the same, but I'd warn against running at lower rpm's for backhoe work. It might be more comfortable in terms of control and noise, but you'll trigger regens much much earlier. When I bought my machine new last year, my first projects were digging, and I ran between 16-1800 rpm for most of it. First regen was at only 18hrs. I bumped the rpms up to 2200, and 2nd regen was at 63 hrs. Since the tech is fairly new, and DPF's are expensive to replace, I'd rather have the longer intervals between regens. Haven't done the math to determine how much more fuel I burn at the higher rpms, but I think it's fairly minimal. Good luck with the oil leak, luckily my machine has been trouble free (so far).