WOW... there are so many uninformed people here regarding they're diesel engines and the fuel they put in them... oil wont hurt your engine
first of all, this isnt meant to get everyone excited or saying that they dont know what they're doing, because everyone has a right to do it how they want to, but information is good. but it is meant to say that concerning any engine, top end or bottom end, a little more lubrication is better than too little..... everyone needs to understand the modern diesel fuels are very low sulfer which has taken a lot of the lubricity out of it.... so without the lubrication in the fuel, you should run an additive, for the longevity of all the moving parts. you dont have to, but depending on your engine and how many hours you put on it will determine how the modern fuel will affect it.
you can buy the high dollar additive which may work better, but in some cases, it is no more than colored hydraulic oil.... sometimes not even colored. it all depends on the brand and the marketing. it is branded as an "additive" and that it may help with (whatever it says on the label) with promises that cant be proven one way or another, then it is stamped with a high price and people buy it thinking they are getting premium stuff, when transmission oil and its properties may be somewhat better and way cheaper. it will not hurt the engine and in most cases will help it.....
it helps clean and lubricate the pump and injectors and people have been using it for years and it is still a very common additive. the advertising and promises that some of the "dedicated" additive companies make have steered the public towards their products,(some people think more money equals a better product) but there are some people who continue with the transmission oil and they have no problems with it.... why change something when you are using a proven product?
a diesel engine will run fine on STRAIGHT transmission fluid without missing a beat.... some of the older diesel engines were actually marketed as multi fuel engines.... one company you may have heard of John Deere, that had several multi-fuel models.. you could run anything in them that would burn.... diesel, kerosene, turpentine, trans fluid, used motor oil, rendered oils, gasoline(they also had spark plugs to help with combustion)..... whatever would burn, or that you could make burn... you could dilute the thicker products with another thinner product that would burn so as to get it to be able to run thru the system....
and they were good engines...
BUT this is not to say you should try it, but in a pinch you can burn about anything in a diesel engine.....as long as its filtered well so it doesnt plug up the injectors and can be made to fire on compression....
if you want to have doubts about what is ok to burn in your engine and mainly the political push and theories surrounding it, think about bio-diesel..... yet people pump it in without another thought.
I can tell the original poster, from many years of real life experience with diesel engines and fuel systems, modern or ancient, the transmission fluid as an additive will definitely do more good than harm to his engine..... no matter whether its a diesel engine or a gas engine. but I will also add that there are some good brand name additives that may be better.....