I am looking to pull our toy hauler which is about 6500 dry and maybe 8000-8500 loaded. I looked today at the code in the glove box and saw was 3:73 gears. Should I upgrade to 4:10, keep in mind we pull over mountains about 1500ft, at places a little steep. I am just not looking to drop 1500 bones to get it re-geared but I also don't want to blow anything up. Thanks.