10R80 Owners - ULTIMATE M6G 10R80 Facts + Resolutions to harsh or no shift conditions

[overd0sed]

Does using 87 vs 91 gas has any affect on smoothness of a10 transmission?

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[Flyhalf]

No but you should really always put 91 anyway.

 

[njweatherman]

Does using 87 vs 91 gas has any affect on smoothness of a10 transmission?

Go with 93 octane from a top tier gas station. The car will run better.

 

[Snopro21]

Read through all the threads on 10 speed. Mine (2020) was harsh shifting in sport plus 4th into 5th. Brought to the dealer had tech check it warmed up. Sure enough from factory it was a quart low. Tech at first didn't believe me. It definitely fixed the issue. I would bet money most are low from factory as mine was.

 

[ChitownStang]

Read through all the threads on 10 speed. Mine (2020) was harsh shifting in sport plus 4th into 5th. Brought to the dealer had tech check it warmed up. Sure enough from factory it was a quart low. Tech at first didn't believe me. It definitely fixed the issue. I would bet money most are low from factory as mine was.

Did you happen to notice if the transmission takes longer to warm up now?
I am curious if low fluid level creates more friction which heats up faster

 

[Snopro21]

Did you happen to notice if the transmission takes longer to warm up now?
I am curious if low fluid level creates more friction which heats up faster

I would say it's about the same.

 

[ZXMustang]

I just sold my whipple GT but I ironically found the best 10r80 tuning by applying the 24gt TCC and shift schedules to my car. It shifted like butter now both at wot and part throttle. I had many other settings changed for tq management as well as shift properties. So it was a mish mash of stuff I pulled in from many sources. But man it was great. Shame it’s gone now.

 

[Cobra Jet]

Read through all the threads on 10 speed. Mine (2020) was harsh shifting in sport plus 4th into 5th. Brought to the dealer had tech check it warmed up. Sure enough from factory it was a quart low. Tech at first didn't believe me. It definitely fixed the issue. I would bet money most are low from factory as mine was.

This is a very puzzling - but as we know - ongoing issue with 10R80 owners, especially for a low mile or possibly “leftover” new car where the 10R80 was not topped off properly.

I myself don’t understand how a new trans can be slapped in at the assembly line but the fluid isn’t being checked…. I get it that the fluid level when cold may meet some level indicator, but Auto Trans fluid should always be checked at normal Op Temps for true accuracy.

From what we have seen just on this site alone from 10R80 owners is it’s been an issue since 2018 and up until 2023 on new S550’s….

I would def suggest to any 10R80 owner to have the trans fluid checked OR if you want to do the DIY check, hit the very first page of this thread, Post #1 and scroll down to the 10R80 fluid check FAQ.

 

[Buldawg76]

I checked mine myself since I have a buddy with a lift in his shop. It was not at the full 206 degrees the manual states but was at about 150 or so and was 1 1/2 quarts low. I bought it used with 5800 miles on it and was checked at about 6200 miles.

I am old skool and will not have a car that does not have a trans fluid dipstick, so I bought a factory dipstick/cap assy for the 10R80 and made a dipstick myself using a factory ecoboost engine dipstick.

I took the fill cap and drilled the center out of it at the top hex end and tapped it to 1/4 NPT threads so a pipe threaded nipple could be installed in the cap and then used some heavy equipment 3/8" ID high pressure hydraulic hose cut to the correct length so the engine dipsticks level marking stick out of the cap the same length as the factory plastic dipstick does when the engine dipstick is inserted in the hose. The engine dipsticks OD is a perfect snug fit for the ID of hose. Then made a bracket that bolts to the rear of the head that secures the top of the hose away from the exhaust and other components under the hood. Then bought some DEI brand heat shielding sleeve from local parts store to slide over the rubber hydraulic hose to protect it from exhaust heat and under hood temps.

So, with homemade tranny dipstick installed I can check my fluid level any time from under the hood when at the correct 206 degrees and can say it is at the exact level the manual states it should be.

My car shifts butter smooth at all times but will add the FP tune in my car also includes trans tuning along with engine tuning.

BD

 

[wynand32]

Go with 93 octane from a top tier gas station. The car will run better.

I wish I could do so myself, but alas, California.

 

[DrewT]

Does using 87 vs 91 gas has any affect on smoothness of a10 transmission?

Not in my experience.

 

[Cobra Jet]

I checked mine myself since I have a buddy with a lift in his shop. It was not at the full 206 degrees the manual states but was at about 150 or so and was 1 1/2 quarts low. I bought it used with 5800 miles on it and was checked at about 6200 miles.

I am old skool and will not have a car that does not have a trans fluid dipstick, so I bought a factory dipstick/cap assy for the 10R80 and made a dipstick myself using a factory ecoboost engine dipstick.

I took the fill cap and drilled the center out of it at the top hex end and tapped it to 1/4 NPT threads so a pipe threaded nipple could be installed in the cap and then used some heavy equipment 3/8" ID high pressure hydraulic hose cut to the correct length so the engine dipsticks level marking stick out of the cap the same length as the factory plastic dipstick does when the engine dipstick is inserted in the hose. The engine dipsticks OD is a perfect snug fit for the ID of hose. Then made a bracket that bolts to the rear of the head that secures the top of the hose away from the exhaust and other components under the hood. Then bought some DEI brand heat shielding sleeve from local parts store to slide over the rubber hydraulic hose to protect it from exhaust heat and under hood temps.

So, with homemade tranny dipstick installed I can check my fluid level any time from under the hood when at the correct 206 degrees and can say it is at the exact level the manual states it should be.

My car shifts butter smooth at all times but will add the FP tune in my car also includes trans tuning along with engine tuning.

BD

Any images of what you did and what it looks like? I’m trying to picture the mod you did and how it works for checking…. But just can’t get the visual on it…

So with your mod, you can pull the dipstick for the 10R80 just like you would for oil and the readings are correct and there are no leaks at the trans?

 

[Buldawg76]

Any images of what you did and what it looks like? I’m trying to picture the mod you did and how it works for checking…. But just can’t get the visual on it…

So with your mod, you can pull the dipstick for the 10R80 just like you would for oil and the readings are correct and there are no leaks at the trans?

Yes, it is identical to any normal trans dipstick in terms of checking the fluid level. I have had it installed for over 10k miles now with no leaks or other issues.

I can get a few pics of it tomorrow to help clarify what it looks like but with the DEI heat shield cover in place you really can't see the hose or fill cap very well.

Keep in mind I have an ecoboost so there is plenty of room in the engine bay, not sure if a V8 would have room to allow for the mod to be accomplished easily. I tried to use a metal pipe such as copper tubing or brake line but could not figure out a good way to seal/attach to the top of the factory fill/dipstick cap.

I am using the fill cap portion of the dipstick/cap assy since its ID is close enough to the diameter needed for a 1/4 NPT pipe thread to be able to drill out the end of the fill cap where you loosen with a wrench and then tap the ID for 1/4 NPT threads. Then just installed a 1/4 NPT threaded fitting with a 3/8" hose nipple into the fill cap and clamp the high pressure hose on the nipple. Then measured the distance from where the plastic dipstick seats on the lower threaded end of fill cap to the correct full level marking on the 10R80 dipstick and cut the hose length so that when the ecoboost engine oil dipstick is inserted in the hose the low/full marking on the dipstick is sticking out the same distance as the plastic 10E80 dipstick low/full markings. So still using the factory aluminum fill cap and green flat o ring to seal to trans housing but with hose and dipstick coming out the top of fill cap.

BD

 

[GTP]

Terrific idea.
Seems like getting the tube length exactly right is super critical.

 

[Cobra Jet]

Yes, it is identical to any normal trans dipstick in terms of checking the fluid level. I have had it installed for over 10k miles now with no leaks or other issues.

I can get a few pics of it tomorrow to help clarify what it looks like but with the DEI heat shield cover in place you really can't see the hose or fill cap very well.

Keep in mind I have an ecoboost so there is plenty of room in the engine bay, not sure if a V8 would have room to allow for the mod to be accomplished easily. I tried to use a metal pipe such as copper tubing or brake line but could not figure out a good way to seal/attach to the top of the factory fill/dipstick cap.

I am using the fill cap portion of the dipstick/cap assy since its ID is close enough to the diameter needed for a 1/4 NPT pipe thread to be able to drill out the end of the fill cap where you loosen with a wrench and then tap the ID for 1/4 NPT threads. Then just installed a 1/4 NPT threaded fitting with a 3/8" hose nipple into the fill cap and clamp the high pressure hose on the nipple. Then measured the distance from where the plastic dipstick seats on the lower threaded end of fill cap to the correct full level marking on the 10R80 dipstick and cut the hose length so that when the ecoboost engine oil dipstick is inserted in the hose the low/full marking on the dipstick is sticking out the same distance as the plastic 10E80 dipstick low/full markings. So still using the factory aluminum fill cap and green flat o ring to seal to trans housing but with hose and dipstick coming out the top of fill cap.

BD

@Buldawg76

Again thanks for the info and sharing!

When you do have time, can you post some images of how it looks and the actual “modified” dipstick after it’s pulled from the trans?

Your posted responses are definitely interesting since the absence of a better way to checking hot 10R80 fluid is a pain point for 10R80 owners…

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