Me, in my infinite wisdom, forgot to run codes BEFORE taking it to a dealer (for an alignment). Thankfully the services they're pushing aren't egregious nor unforseen for all her 23,000 miles, but alas I'm NOT willing to spend $1k on a brake fluid change, transmission flush (on a 6 speed), and fuel injection cleaning. My last car was a '94 Miata, so suffice to say I'm used to working on a... Specific type... Of car. My main 2 questions are:

1. Transmission fluid flush. My 2020 is a 6 speed and from what I know doesn't need a flush at this point, but it's supposedly recommended to change every 15k to 30k miles. I'd like to do it now/soon, is there a good video/written guide on where everything is located on a 6 speed? Anything I should do while I'm here? I've done basic trans work before. Also every guide I've seen is for CVT, I've only worked on manuals, so not sure if plugs/bolts/etc will be in much different locations, or style of servicing.

2. Fuel injection cleaning, never done this one before, and I'm not in a rush to do it since she shows no injection-related issues. How difficult is this with a kit, and again any good guides on this? Also I'm wary of cleaners in general, I know some people put (non-silicone) cleaners in their cars twice a year, is this recommended, and doesn't do any damage right? Again, anything I should do while I'm here?

I'd love to make my car last for a couple decades, so if yall have any recommendations for other annual services I should stay on top of let me know this is the first car I've had that's not only newer, but is also much younger than me lmao.

 

Welcome. Not sure what the dealer is charging you for each service, but here goes.

Tranny flush: Absolutely, every 30K at the least. Should be around $100 if you have someone else do it, obviously cheaper if you do it. I have a CVT so unfortunately no help on how to access MT fluid.

Fuel injector cleaning: Forget it. The best thing you can do is run Top Tier fuel exclusively, as these engines are prone to carbon buildup. The kind of cleaning they're offering is of no help with carbon buildup unless they're taking the engine apart and doing media blasting. Save your $.

Brake fluid - Yeah, you want to do that every 30K just like the tranny. Again, shouldn't cost that much, so how they got you to $1K at this point is a mystery.

I'm thinking any dealer who recommends fuel injector cleaning is one I don't ever want to go back to. That's a pure profit item that does absolutely nothing. My vote would be anywhere else.

 

Since I'm too lazy to work on my 2015 Fit 6 speed I go to my local Honda Dealer for all recommended work and service.

 

I am not aware of any normal manufacturer who recommends a "flush" for anything. No engine flush, no transmission flush, no radiator flush, no brake fluid flush, etc. All recommendations from manufacturers are simply drain and refill. I've come to the conclusion that the "flush" was invented by shops to boost their profit margins since I simply can't think what they do for your car.

 

Changing the trans fluid is quite easy. I have a 2016 Fit with 6MT as well and was able to access the fill hole by removing the aircleaner assembly, then snake a hose into the fill hole. I purchased a 2 foot section of plastic tubing from the hardware store for this task.
The first change will be a real hassle as the factory really has the plugs in there tight!
Also, make sure to remove the fill hole BEFORE the drain plug. Nothing worse than removing the drain plug to end up not being able to get the fill plug out.

As for interval, the MT don't need the fluid changed as often as the CVT transmissions do, so you can address this at anytime that works best for you.
Even under abuse, Honda MT's are very stout and durable.