My coworker was telling me that he occasionally put a quart of cheap transmission fluid in his fuel to help clean the injectors, is this a common practice or has anyone heard of this?

most around here use 2stroke as additive or regular diesel additive. Some good reading here http://www.dieselplace.com/forum/showthread.php?t=178848&highlight=lubrication+study

Do not use ATF in a common rail system.

Do not use ATF in a common rail system.

x2. This is true for older Diesels, but DO NOT do it on a Common Rail System. Only use REAL Fuel Additives.

just wonder why no atf in common rail?

Probably has something to do with lubricity and the sensitivity of the injectors.

just wonder why no atf in common rail?


I'm also curious. I just dumped about a quart of new atf in 100 gals of fuel. Will I be safe?

I think it has to do with the detergent in the ATF.

http://www.dieselplace.com/forum/showthread.php?t=148169&highlight=atf

Contrary to popular wisdom, transmission fluid isn't particularly slippery. It's formulated with with friction enhancers that keep clutches and bands in the trans from slipping under normal use. I can't think of a worse additive for your injectors unless your intention was to damage them.