Differential and MT-86 transmission fluid change track

[Walt]

My Mustang is mostly a garage queen which is mainly used for weekend cruises (both cold winters and hot summers) and track days. It's a 2017 model year so it's about 3 years old now and has +-5000 miles. I have done about 5 track days with it (road course).

Should I change the manual transmission fluid (MT-82) and the differential fluid? I can't really find any interval information in my owners manual, it just says that it doesn't have to be changed unless you drive through standing water. For severe usage it says see approved dealer.

What fluids (and viscosity) would you recommend and how often should they be replaced (based on my usage)? I've heard many good things about the BG Syncro shift II fluid, but I can't seem to find it locally here in Europe.

Thanks,
Walt

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[Elp_jc]

I'm going to change all drivetrain fluids at 1K miles, which is about a week away. It's never too early for the first time IMO, to get rid of all the assembly and break-in crap. So I think it's smart for you to do it now. I'm exaggerating a little, but since it's very easy to do, want to have clean fluids in there from now on. And also since the car had 66 miles when I bought it, it could have been abused a lot.

As far as fluids, for your non-D4 tranny, people swear by the BG Synchro Shift II fluid, so I'd probably use that one. With newer D4 versions like mine, there's hardly any difference reported, so I'll probably switch to the Ford-approved Redline DCT-F fluid. Having said that, there's a Motorcraft MT-82 additive that Steeda sells that if added to the OEM DCT fluid, it might behave like the BG fliud, but since nobody has reported that combination yet, I'd probably go for one of the 2 I mentioned.

Finally, the more controversial issue is which viscosity to use with the differential. I have the Torsen, but both come stock with 75W85. The choices are that, plus 75W90, 75W110, and 75W140. I called Optimum Performance, which is a distributor of BG fluids, and they recommended 75W140, even when I'll never track my car. They say it protects the diff much better, and if not really hot, that the viscosity is very similar. I live in hot TX, but it also gets cold, so not sure what to do about that. Oh, and still undecided between BG and Redline. Let's see if we can hear more opinions here .

 

[Walt]

I'm going to change all drivetrain fluids at 1K miles, which is about a week away. It's never too early for the first time IMO, to get rid of all the assembly and break-in crap. So I think it's smart for you to do it now. I'm exaggerating a little, but since it's very easy to do, want to have clean fluids in there from now on. And also since the car had 66 miles when I bought it, it could have been abused a lot.

As far as fluids, for your non-D4 tranny, people swear by the BG Synchro Shift II fluid, so I'd probably use that one. With newer D4 versions like mine, there's hardly any difference reported, so I'll probably switch to the Ford-approved Redline DCT-F fluid. Having said that, there's a Motorcraft MT-82 additive that Steeda sells that if added to the OEM DCT fluid, it might behave like the BG fliud, but since nobody has reported that combination yet, I'd probably go for one of the 2 I mentioned.

Finally, the more controversial issue is which viscosity to use with the differential. I have the Torsen, but both come stock with 75W85. The choices are that, plus 75W90, 75W110, and 75W140. I called Optimum Performance, which is a distributor of BG fluids, and they recommended 75W140, even when I'll never track my car. They say it protects the diff much better, and if not really hot, that the viscosity is very similar. I live in hot TX, but it also gets cold, so not sure what to do about that. Oh, and still undecided between BG and Redline. Let's see if we can hear more opinions here .

Yeah it's probably a good idea to change it anyway to remove the break-in shavings and such. It doesn't seem to be too difficult once you get the car on jacks. Just drain the fluid and pump in the required amount of fluid stated in the manual, or just fill it until it starts coming out again like some do. Although my European manual just says "see approved dealer" instead of a fluid capacity rating.

I didn't know there were differences between the MT-82 versions used for the s550 platform, good info! I have a performance pack ecoboost so I guess I have a Torsen too? Don't know if it's any different since I have a EU-spec car and the performance, premium packages are standard.

I'll probably get 75W140 too then, since they're all 75W I'd assume they have similar properties when cold. I don't know if I can make the change before my next track day at Spa, but I think I'll change both soon and then just change it annually.

 

[Elp_jc]

I think just the GT PPs (both 1 and 2) have the Torsen, but not absolutely sure. Maybe somebody else can verify that for you. And the latest version of the MT-82 (D4) started with 2018 cars. I really like the new gear ratios, but I won't track my car. The new one is called 'D4' because 4th is 1:1 now. With yours, it was 5th, and some folks like it better for track duty, since you have 5 gears up to 1:1, rather than just 4. But I like 5th because it's more or less between 4th and 6th. In yours, 6th is a huge drop from 5th. And I travel a lot, so use 5th and 6th quite a bit when traveling, and the jump in rpm is very decent. From 1.00 to 0.6x is huge, so if you have to downshift from 6th to 5th, the rpm jump a lot more than necessary. But it's all a matter of preference. I MUCH prefer the new ratios, so I'm happy with the new version. Plus it has many improvements too.

 

[EFI]

I'll probably get 75W140 too then, since they're all 75W I'd assume they have similar properties when cold.

That's an incorrect assumption. One would think that the XXw number would all mean the same viscosity at cold, but the 2nd number also has something to do with it and if it's higher it will be thicker throughout the range both cold and hot. It's alot like engine oil, a 5w50 is alot thicker at cold startup than a 5w20 even though both have the same 5w.

But you should still be using the 75w140 if used on track as it provides a little better protection when it gets super hot.

 

[Walt]

That's an incorrect assumption. One would think that the XXw number would all mean the same viscosity at cold, but the 2nd number also has something to do with it and if it's higher it will be thicker throughout the range both cold and hot. It's alot like engine oil, a 5w50 is alot thicker at cold startup than a 5w20 even though both have the same 5w.

But you should still be using the 75w140 if used on track as it provides a little better protection when it gets super hot.

Makes sense, didn't think about that. Would you still recommend 75w140 if the car is used on the street as well? I drive when it's freezing too or even do a track day close to freezing temperatures. Any downsides when using 140 vs 90?

 

[EFI]

Makes sense, didn't think about that. Would you still recommend 75w140 if the car is used on the street as well? I drive when it's freezing too or even do a track day close to freezing temperatures. Any downsides when using 140 vs 90?

Yes you should definitely run 75w140. I've been using that on my car for going on 4 years now and it's also a daily in the winter and summer. No issues as long as you let your fluids come up to temperature before you beat on it.

The downside is a little more drag and a little less efficiency but nothing that you would ever notice.

 

[PRG3k]

None of the Ecoboost's come w the Torsen. For that reason also, I think all of our diff's need the friction modifier as well.

 

[Superspirit]

None of the Ecoboost's come w the Torsen. For that reason also, I think all of our diff's need the friction modifier as well.[/QUOTE

Not entirely correct, the wife's Ecoboost performance pack car has the torsen 3.55

 

[PRG3k]

Not entirely correct, the wife's Ecoboost performance pack car has the torsen 3.55

I just saw they started putting it in the 2018's+. Thanks for the correction.

 

[Elp_jc]

Hey gang, since this thread was about the MT-82, and not the differential, I'm steering it back to subject . Talked yesterday with a Redline tech support guy, after not finding their DCTF fluid listed for my 2019 Bullitt, and he said it's because it doesn't meet Ford specs, which really surprised me. That was the reason I was going to use it. Ha ha. Now what? At least it's a DCT, which is what the tranny has from the factory. The BG fluid is not a DCT, so I assume thicker than DCT, which could negatively affect its winter operation making the tranny even notchier? At only 1K miles, should I stick to the Motorcraft fluid? Wanted to change to a better fluid, to see if the slight notchiness goes away, and also the 2-3 'nibble', but they reportedly go away on their own after some break-in. Comments welcome.

 

[Walt]

What transmission and differential fluid would you recommend if BG products are not available? Motorcraft fluids are not available in Europe and my dealer won't to tell me what they use so... . Anything from Motul, Ravenol, Castrol, ... that's as good or better than BG Products? Like I said it needs to whitestand both trackdays (cold or hot) and daily driving (even at winter).

 

[thelostotter]

Hey gang, since this thread was about the MT-82, and not the differential, I'm steering it back to subject . Talked yesterday with a Redline tech support guy, after not finding their DCTF fluid listed for my 2019 Bullitt, and he said it's because it doesn't meet Ford specs, which really surprised me. That was the reason I was going to use it. Ha ha. Now what? At least it's a DCT, which is what the tranny has from the factory. The BG fluid is not a DCT, so I assume thicker than DCT, which could negatively affect its winter operation making the tranny even notchier? At only 1K miles, should I stick to the Motorcraft fluid? Wanted to change to a better fluid, to see if the slight notchiness goes away, and also the 2-3 'nibble', but they reportedly go away on their own after some break-in. Comments welcome.

The BG fluid has worked fine for me for the past couple years. It assists with the things you mention but it doesn't cure it completely. Installing the Blowfish racing shifter bracket made a much more appreciable difference in my experience.

Red Line MT-LV (I think it is a new product?) says it is a suitable replacement for Ford XT-11-QDC and I plan on trying it next time I replace the fluid.

 

[Elp_jc]

Thank you for that info. You know, decided to wait on the tranny and differential until next oil change, to give them a chance to fully break in, and see how the tranny feels after 5K more miles. I might decide there's no reason to switch, and keep using OEM fluids. We'll see. Please post results after you switch to that new Redline fluid.

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