Answer
Feb 27, 2022 - 10:12 PM
Hi!
Since you are referring to "transmission" fluid used in an engine, I would tend to think that you are referring to how engine oil was once used interchangeably in manual transmissions, for instance in older Hondas. However, it's important to understand that things changed a lot since then, so let's start by clearing some things out.
While it's true to say that 5W20 engine oil is similar in thickness to 75W90 gear oil, very different additives are added by the manufacturers to cater to the very different needs and conditions of both components. When it comes to older vehicles, it's also true that in some cases, engine oil could be used instead of gear oil, especially since engine oil was significantly cheaper, but never the other way around.
However, these older trannies were much simpler, contained much fewer sensors, and relied a lot less on operating data (not to forget that we are talking about manual gearboxes here; never automatic one).
Nowadays, transmissions are much more delicate, and as a general rule, should only be filled with the manufacturer's recommended oil type and grade — same for the engine.
In this case, the manufacturer recommends the use of API-certified SAE 5W-20 engine oil and MOPAR ATF+4 automatic transmission fluid — anything else would just prove to be detrimental to your engine and transmission in the long run.
If you need any help changing either your engine oil or transmission fluid, take a look at this 2013 Chrysler 200 Service and Repair Manual. You'll find every service and repair procedure you might ever need in there! ✌
