Hello everyone and let me begin. I have owned a auto repair shop for 20+ years and am semi retired. I have Tn mountain property that I want to build my last home, and for some reason i thought it was good idea to buy a dozer to fix it the way I want. I got a 1995 cat d4c series 3 6yl1 from a 78 year old gentleman who hasn't keep up maintenance very well the last few years and no records. I did find out from others that the engine and trans have been rebuilt in last 3 to 4 year. Seem to run and push hard. Looking for sources for used parts or where to new parts besides Cat. I was going to change all filters. On pulling plugs on trans, finals, etc. the fluid looks good but should I pull samples and have tested or just change all or since it looks goods don't change. I was of course change engine oil and filter. I just wounding how others would start this process if they had did the same. thanks