Looking for a cheaper alternative fuel source for your diesel Powerstroke? Maybe you work in for an automotive shop, know someone who does, or if you have access to used transmission fluid by the drum load, either way I may have some good news for you. Diesel trucks will burn almost anything* and transmission fluid is one of the more efficient choices. Extra benefit - smells great.
This is a pretty debatable topic in alternative fuels. Let's just start by saying that putting anything in your fuel tank besides the fuel that it requires always has the possibility of doing damage either immediately or in the long run. These methods are tried and tested by me, by to a small degree, but if you are unsure about taking a risk then maybe you shouldn't try this at home.
The first requirement is that you are driving a compatible diesel engine. Here at Expertswrite, I will be focusing on Ford Powerstrokes. I do know that some other diesels from Volkswagen, Mercedes-Benz, Cummins, and Duramax may be compatible based on the years produced. I do not have that information handy but if someone wants to email me their experience, I will surely share it.
Ford has offered several diesel engines over the last few decades. Pre-Powerstrokes were 6.9L and the 7.3 IDI. These engines will run on almost any petroleum product. If any damage is done to the injectors, they are easy and cheap to replace. I have seen reports of successfully running it in the 7.3L IDI. Not many of those are on the road these days...
Once the Powerstoke name came about, they offered the 7.3L, 6.0L, 6.4L, 6.7L. This is very important: You CAN ONLY use transmission fluid in the Powerstroke 7.3L made from Mid-1994 to Mid-2003. A 6.0L Powerstroke will run on it, but those injectors are finicky as is. They don't seem to like it and most likely will cause even earlier premature injector failure. One advantage you do have over the 7.3L Powerstroke is an additional filter. If transmission fluid is used as a fuel in either the 6.4L or 6.7L, it can certainly destroy all the high pressure fuel side components (injectors, pump). Those newer Powerstrokes that are high pressure fuel fed are very sensitive to any particles in the fuel.
My first hand experience came from my boss. He is the owner of the Ford Dealer I am employed by. He has driven many different models of diesels over the years. Specifically lately, he drives a 1999 F250. Its pretty amazing what he does with the transmission fluid. When we do a transmission flush, the machine outputs old transmission fluid into a 5 gallon container. We usually let this container sit for a day. We only do that because we generally empty them the start of the next day. He takes that approximately 3 gallons of unfiltered transmission fluid and pours it directly into his fuel tank. He doesn't add anything to it. He doesn't filter it - Just adds it straight. Being this is a Ford Dealer, we are burning Mercon V. He always recommended against using SP or LV.
He has been doing that for years into that same truck and others of his with no adverse effects. They smell slightly different, but he claims he feels no noticeable loss of power even when pulling a trailer. He doesn't even add in a few gallons of diesel fuel here and there in an attempt to dilute it slightly.
To me, that sounds scary. I have been talking to other guys who run with transmission fluid as fuel and they do have some recommendations. One fella has a 55 gallon drum at home that he puts fluid into. He then uses a hand pump to push fluid through a standard oil filter then directly into his tank. He has had success doing that for approximately 10 years in his 1995 F250.
Some other guys that I talked with had a even more elaborate systems. They would have a drum with a drain in the bottom of it, filled with fresh used transmission fluid. They would add around 5% gasoline to that tank and allow it to sit for approximately 48 hours, drain a little out of the bottom getting some really nasty stuff that they would trash. They then would use a pump to transfer the fluid through a 5 micron filter, through a 3 micron filter, to another drum. That second drum would be used to actually fill their fuel tanks.
UPDATE ::10/27/2015:: It has been two years since I originally wrote this article and all the while I had been using transmission fluid as my diesel fuel. I am happy to report that no problems have occurred. The truck has gained approximately 30K miles over these last two years. The truck did not have transmission fluid as fuel for all those miles and mostly I try to dilute 50% with diesel. At 210K miles on the odometer, I wouldn't even break a sweat or blame the fuel if an injector or two would fail because of the mileage and original injectors. Even use the SP and LV fluids.
UPDATE ::09/16/2016:: Ah, another year passed and hundreds of gallons of transmission fluid used. Finally had a tired injector that needed replacing. I actually came across a 4 used AD code injectors and mixed them in on every other cylinder in the firing order, but with 225K miles and counting I never sweated it.