10R80 safer way to flush?

[rsonni]

I'm looking to do a transmission fluid change on my 2021 GT PP1 and found this video that suggests an interesting way of flushing the entire system:



I have zero experience in this kind of thing, but is this something that can be done with the 10R80? From what I've read we have no drain plug and no way to fill it from under the hood. But if I was able to disconnect a line running from the trans cooler to the trans, would I be able to flush the system by refilling at the fill plug/dipstick? If it's possible, does anyone know which line to disconnect? I was thinking I'd do it at smaller intervals like 1 quart at a time just to play it safe.

Is this a bad idea? Again I've never touched a transmission before but I'd like to avoid dropping the pan at all costs. I'm not due for a filter replacement but I suspect I have burnt fluid after a little overheating at the track, and I'd like to see if new fluid helps with shifting.

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[MiamiGT350]

Just because an idea might work doesn't mean it is a good idea. I would be very averse to any procedure that involves running the transmission with reduced fluid levels. Seems risky imo.

I would do it the right way or pay someone who knows how.

 

[MAGS1]

Just because an idea might work doesn't mean it is a good idea. I would be very averse to any procedure that involves running the transmission with reduced fluid levels. Seems risky imo.

I would do it the right way or pay someone who knows how.

I like his videos, he explains things in pretty simple terms. I personally wouldn’t tackle the 10r80 fluid change, especially on jack stands. Looks like a pain in the ass

 

[MiamiGT350]

I like his videos, he explains things in pretty simple terms. I personally wouldn’t tackle the 10r80 fluid change, especially on jack stands. Looks like a pain in the ass

If the GT has a transmission fluid dipstick and a drain plug (I don't happen to know), I suppose you could try to drain out the bottom and fill at the dipstick, equal to the fluid amounts you drained.

I don't think I would try to do anything more than that.

 

[MAGS1]

If the GT has a transmission fluid dipstick and a drain plug (I don't happen to know), I suppose you could try to drain out the bottom and fill at the dipstick, equal to the fluid amounts you drained.

I don't think I would try to do anything more than that.

The fill location is a pain in the ass. The plug/dipstick is hard to get to and if your car has been running you’ll burn yourself. First post in this thread has a few good pictures

https://www.mustang6g.com/forums/threads/a10-fill-plug-impossible-to-remove-help-plz.141548/

 

[MiamiGT350]

This post looks useful for @rsonni

https://www.mustang6g.com/forums/th...ssible-to-remove-help-plz.141548/post-2900858

 

[Optimum Performance]

Go to BG's website and find a local BG shop to do a real fluid exchange. BG spends a ton of money on R&D to make these services 100% effective.

https://bgfindashop.com/

 

[MAGS1]

Go to BG's website and find a local BG shop to do a real fluid exchange. BG spends a ton of money on R&D to make these services 100% effective.

https://bgfindashop.com/

That’s good info thanks. My dealer that does all my service work is a gold shop, never knew that.

 

[Optimum Performance]

That’s good info thanks. My dealer that does all my service work is a gold shop, never knew that.

There ya go

 

[bankyf]

I've done what you are proposing with a 6r80 and it worked well. In reality, it's the same way a BG transmission fluid exchange machine works. The problem with most newer Ford's is that it is difficult to get it up to and maintain operating temperature to open the thermostat so fluid flows through the cooler lines.

 

[rsonni]

Thanks all for the feedback – an update for anyone interested.

I purchased everything I needed to flush the transmission and got the car up on stands a few days ago. I bought a manual pump to pull fluid from the filler hole and pump the same amount of new fluid in. I'd also disconnect the line coming from the trans cooler, start the car to drain 1 quart, pump in 1 quart, and repeat until it was all clean.

The first thing I did was measure the fluid level cold, and it threw the entire plan out the window.

According to things I've read and FordTechMakuloco's video, the cold fluid level should be under the 6 and fully warmed up should be between 5 and 6. My cold fluid was at the 3. I measured it at least 5 times because I couldn't believe it. I guess that explains why my temps shot up to 230° during the last track day and spat some out onto the exhaust. Ford....what the f*ck???

The color of the fluid was good so I didn't see a need to spend the effort on a full flush. I was only able to pump out 2 quarts from the hole and put a small amount in to get the cold level under the 6.

I've heard of these things being underfilled from the factory but haven't heard about overfilling. I'm just hoping it didn't damage anything. Check those levels people!

 

[K4fxd]

Was that cold with the engine running?

 

[Cobra Jet]

Thanks all for the feedback – an update for anyone interested.

I purchased everything I needed to flush the transmission and got the car up on stands a few days ago. I bought a manual pump to pull fluid from the filler hole and pump the same amount of new fluid in. I'd also disconnect the line coming from the trans cooler, start the car to drain 1 quart, pump in 1 quart, and repeat until it was all clean.

The first thing I did was measure the fluid level cold, and it threw the entire plan out the window.

According to things I've read and FordTechMakuloco's video, the cold fluid level should be under the 6 and fully warmed up should be between 5 and 6. My cold fluid was at the 3. I measured it at least 5 times because I couldn't believe it. I guess that explains why my temps shot up to 230° during the last track day and spat some out onto the exhaust. Ford....what the f*ck???

The color of the fluid was good so I didn't see a need to spend the effort on a full flush. I was only able to pump out 2 quarts from the hole and put a small amount in to get the cold level under the 6.

I've heard of these things being underfilled from the factory but haven't heard about overfilling. I'm just hoping it didn't damage anything. Check those levels people!

be careful - there are MULTIPLE 10R80 dipsticks out there - don't know why, or the reason, but it's fact. I've documented them here:
2 threads on checking 10R80 fluid levels:
https://www.mustang6g.com/forums/threads/10r80-fluid-check.137537/#post-2827033

This thread discusses the (2) very different 10R80 dipsticks - thanks to @leonrudi and @speedup for their findings!):
https://www.mustang6g.com/forums/threads/a10-fill-plug-impossible-to-remove-help-plz.141548/

Owners cannot base a 10R80 fluid level dipstick reading for a Mustang comparing it against an F150 or any other product... the sticks are different between products thus the reading are different. Plus, we have also seen dipsticks with different markings as well (again but sure why).

As we know, most are under filled - again that question has never been answered either as to "why".

I haven't heard of many being overfilled...

What did you use as a reference to determine the reading on the stick; the threads here, a manual or another online source? Just curious.

The above threads came out of our main 10R80 FAQ's thread, within post #1:
https://www.mustang6g.com/forums/th...tions-to-harsh-or-no-shift-conditions.135463/

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