So I'm sure this question has been ask/answered quite a bit, so I apologize. I've got a 2012 FX2 5.0 and they told me the last time I took it in for brakes and the oil change that my transmission fluid was dirty and needed to be flushed. They also mentioned I have a leak in my rear diff and that needed to be done as well. My question is that my truck is at 82k miles and I've read that doing a flush can cause more harm than good. I'm not having any tranny issues at all. Every now and then a hard shift into reverse or park, but nothing that's out of the ordinary. So any advise would be great. Thanks!

 

I had my 2011 flushed at 100k miles. Worked great afterwards. I am about to do my 2018 at 50k miles. I tow a heavy travel trailer for about 25% of my miles . I would flush it.

 

Not sure what year it went itno effect but I saw a YouTube video recently indicating a flush won't actually work, at least on the 6 speed.

Fordtechmakuloco did a transmission lead frame swap. At one point he mentions how the thermo valve (forgot what it is) is sort of a pain to get back in without it slipping our during valve body (or maybe filter) installation. Anyway, the comment was that the valve won't open until a certain temp.
He goes on to mention how the shops that do a flush circulate out 17 quarts of fresh oil without out going into the transmission.

Yes, I've missed a few details there. Also maybe some mechanic from here can prove how it would work, such as if the vehicle is running at normal operating temperature during the flush, etc. I've had or seen a transmission flush take place to know what the process is.

Anyway, take a look for his YouTube channel with a video titled something like lead frame replacement.

 

No flush here, just fluid and filter change. I thought 161K miles was ‘bout time.

 

IF the rear diff is leaking get it fixed by another shop. I'd get a 2nd opinion on that. This shop is trying to rip you off. No need to service the transmission any time soon and with that lie I'd be concerned with the truth about the rear diff. Sounds like you're using a dealer. They offer free, or cheap oil changes as an excuse to get people into the shop and try to talk them into unnecessary repairs. Happens all the time.

 

The invoice from my last dealership oil change gave me green checks on everything, including my 70,000 mile brakes.

No suggestions for unnecessary service. So maybe it isn't all dealerships.
I had synthetic installed previously -they commented that it wasn't necessary but I could, both are fine but the synthetic costs more. They were upfront about everything. I switched to the Ford blend this time and they said similar, both are fine if I wanted to go with blend.

I am going to have the transmission serviced, but not by the dealership most likely (because of cost).

 

It probably makes more sense to pull the dipstick and check the condition of the fluid to verify the claim made by the shop than it does to just assume they are lying. None of us actually know what kind of condition the Op's truck is in. I know its a pain to check the dipstick underneath the truck, on the side of the trans when compared to checking a dipstick under the hood, but it's still really not that hard and only takes a minute or two.

 

Yeah, I was kinda thinking the same thing. After my brakes, they keep pushing it. It’s a local big Power Ford dealership here in NM. I wish I could do it myself but I don’t live in a house anymore.

Overall my truck is in very good condition. Mechanically speaking I’ve never had any issues, and the maintenance records from the previous owners ( 2 before me) was all oil changes and tires.

 

Transmission flush at my dealer are complete flushed, we put in 12 new quarts and take out 12 old quarts.
1 - Rack the vehicle up on a lift, wheels a few inches off the ground.
2 - Open transmission line connector where technician wants to, input adapters to the connector that have a fitting like an air hose fitting.
3 - Put 12 quarts of new fluid in the new fluid tank and make sure the old fluid tank is empty.
4 - Using IDS bring up the trans temp data.
5 - Start the vehicle, put it in gear and power brake, this is braking while revving the engine up, I do not go above 1500rpm.
6 - Keep power braking while watching the trans temp till you reach 190 degrees, which is where the thermostat opens for 90 percent of Fords.
7 - The flush machine will beep when fluid movement starts, listen for this beep then hit the start flush button on the machine.
8 - Keep power braking around 1000rpm to keep fluid pressure at required level.
9 - Watch the new fluid and old fluid level indicators on both jugs, the flush machine matches the amount of new fluid that goes in to the old fluid that comes out.
10 - The flush machine will beep a few times when 12 quarts has been flushed out.
11 - Put vehicle int park and leave engine running, lift vehicle up and check fluid level using trans dipstick, add fluid as needed to bring to correct level.
12 - Lower vehicle, turn off, remove transmission lines adapters and reconnect vehicle transmission lines.

 

Ford doesn't recommend flushing transmission for maintenance just the drop and fill of the pan. Flushing requires special equipment that can heat the new fluid so the thermostat doesn't close with the introduction of new cold fluid.