A little history!
Several months ago I noticed the truck (engine) was getting a little noisy, louder than normal, It does have 120K on the odometer! After reading allot of the post's on here and on some other forums this is what I did.
I changed ALL fluids in the truck, font to back! $300. worth.
I put Rotella 5w-40, 15 qts synthetic in the eng, Mercon 18+ in the transmission, Napa antifreeze almost 6 gal (the one for diesel engines) Synthetic 75w-90 2 qts plus 6oz of the limited slip additive in the rear end. At every fill up I put 1 bottle of diesel power additive (cetain booster) and 32 ounces of Marvel Mystery oil. Since then, its been about 3 weeks now, The engine is at least 30% quieter and runs much smoother.
I expected some results but not the amount I did get!
For those of you with an engine that seems a little noisier than is used to be, Give this a try, The synthetic eng oil and additives to your fuel, It works.
Rich

 

Yeah I've noticed that the ULSD makes my engine louder than running a mix of offroad/home heating oil........man she really loves that stuff.....there something to be said about feedin it alittle sulfer