[fleetfoot]

Over the last 100,000 miles in my e92 328i and 100,000 miles in my old Acura TSX, I always changed the transmission fluid every 30,000 miles. And after every flush, the shifts always felt smoother. I think there's definitely some fluid degradation that happens despite the "lifetime" fill guidance. I use Redline MTL now and previously used GM Synchromesh FM in the Acura.

I had my e92 in the shop this week for my SECOND leaking valve cover gasket, so I went ahead and had them do a transmission fluid flush even though my fluid was only 2 years and 20,000 miles old. And there was still a noticeable improvement in shift action. It feels like the synchros aren't working as hard.

So from now on, my MT fluid changes are going to happen every 2 years or 30,000 miles, whichever comes first.

[E93Dude]

Originally Posted by fleetfoot

Over the last 100,000 miles in my e92 328i and 100,000 miles in my old Acura TSX, I always changed the transmission fluid every 30,000 miles. And after every flush, the shifts always felt smoother. I think there's definitely some fluid degradation that happens despite the "lifetime" fill guidance. I use Redline MTL now and previously used GM Synchromesh FM in the Acura.

I had my e92 in the shop this week for my SECOND leaking valve cover gasket, so I went ahead and had them do a transmission fluid flush even though my fluid was only 2 years and 20,000 miles old. And there was still a noticeable improvement in shift action. It feels like the synchros aren't working as hard.

So from now on, my MT fluid changes are going to happen every 2 years or 30,000 miles, whichever comes first.

That's encouraging to know, since I'm getting ready to replace tranny fluid on my '07 335 MT with 100K this weekend. Am using the exact same fluid. Looking forward to some noticable affirmation that my car appreciates me.

[Phil325i]

Good to know. I do my diff fluid at the same time.

[edycol]

Originally Posted by fleetfoot

Over the last 100,000 miles in my e92 328i and 100,000 miles in my old Acura TSX, I always changed the transmission fluid every 30,000 miles. And after every flush, the shifts always felt smoother. I think there's definitely some fluid degradation that happens despite the "lifetime" fill guidance. I use Redline MTL now and previously used GM Synchromesh FM in the Acura.

I had my e92 in the shop this week for my SECOND leaking valve cover gasket, so I went ahead and had them do a transmission fluid flush even though my fluid was only 2 years and 20,000 miles old. And there was still a noticeable improvement in shift action. It feels like the synchros aren't working as hard.

So from now on, my MT fluid changes are going to happen every 2 years or 30,000 miles, whichever comes first.

For those living north of ATL, I would go MT-LV in gearbox or D4. I have currently D4 in gearbox and shift exceptionally well.

[nicholasn]

Originally Posted by fleetfoot

Over the last 100,000 miles in my e92 328i and 100,000 miles in my old Acura TSX, I always changed the transmission fluid every 30,000 miles. And after every flush, the shifts always felt smoother. I think there's definitely some fluid degradation that happens despite the "lifetime" fill guidance. I use Redline MTL now and previously used GM Synchromesh FM in the Acura.

I had my e92 in the shop this week for my SECOND leaking valve cover gasket, so I went ahead and had them do a transmission fluid flush even though my fluid was only 2 years and 20,000 miles old. And there was still a noticeable improvement in shift action. It feels like the synchros aren't working as hard.

So from now on, my MT fluid changes are going to happen every 2 years or 30,000 miles, whichever comes first.

Good to hear. I will try to do a transmission fluid change in my 328 soon, as going through the gears isn't as smooth as I'd like. I believe I put Pennzoil Synchromesh in my GTI when I replaced the clutch in it about 16k miles ago, and despite having a lot more miles than my 328, it goes through the gears much more smoothly (at least once the fluid is up to temp - when it's cold, you're double-clutching through every gearchange, lol).

[E93Dude]

Did my manual transmission fluid exchange this past weekend with the Redline. At 100k miles, the old stuff was black... New fluid looked like honey, smelled MUCH better that the wretched rear differential fluid I exchanged a few weeks ago. Car now shifts almost exactly....the same. Wasn't all that knotchy before, but is now maybe a little smoother. I don't care. At that mileage, it needed the refresh, so no "ragrets"....

[mapleleaf1773]

That movie was hilarious

[fleetfoot]

Originally Posted by E93Dude

Did my manual transmission fluid exchange this past weekend with the Redline. At 100k miles, the old stuff was black... New fluid looked like honey, smelled MUCH better that the wretched rear differential fluid I exchanged a few weeks ago. Car now shifts almost exactly....the same. Wasn't all that knotchy before, but is now maybe a little smoother. I don't care. At that mileage, it needed the refresh, so no "ragrets"....

Just a hypothesis, but I wonder if you go 100k before changing transmission fluid do you wear the synchros to the point that even new fluid doesn't make them feel any better?

As I mentioned, my forward gears are easier now...but the biggest difference was actually reverse gear. I was really struggling with that gear sometimes. No issues at all since the flush.

[E93Dude]

Originally Posted by fleetfoot

Just a hypothesis, but I wonder if you go 100k before changing transmission fluid do you wear the synchros to the point that even new fluid doesn't make them feel any better?

As I mentioned, my forward gears are easier now...but the biggest difference was actually reverse gear. I was really struggling with that gear sometimes. No issues at all since the flush.

Sure, you may have a good point. I should have changed the MT fluid at 50-60k, but I didn't. Regardless, if the synchros have worn down a bit over the years, at least I got rid of a good amount of the microscopic (or larger?) metal residue circulating in the old fluid that for sure wasn't helping anyone. I've been pretty religious about changing oil, coolant and brake fluid, anyway.

[skpatel1975]

Redline's website says to use "D6 ATF" fluid for my 2009 E92 6MT. Probably will be the first transmission fluid change at 64K miles.

Anybody use D6 ATF fluid in the manual? Confused to say the least. Inclination was to get Redline MTF but seriously confused now.

Thanks In Advance.

[Phil325i]

I use this with no issues:

https://www.amsoil.com/p/manual-sync...uid-5w-30-mtf/

[mapleleaf1773]

Since its your transmission, I've always put back in what the manufacturer uses, period. Who else knows the car better? So for my 328 6mt I use the bmw stuff. Expensive but not as expensive as a new transmission.

https://www.fcpeuro.com/products/bmw...ml-83222339221

[edycol]

Originally Posted by mapleleaf1773

Since its your transmission, I've always put back in what the manufacturer uses, period. Who else knows the car better? So for my 328 6mt I use the bmw stuff. Expensive but not as expensive as a new transmission.

https://www.fcpeuro.com/products/bmw...ml-83222339221

BMW is using basically ATF stuff.
The reason is twofold:
1. People complaining about shifting during cold weather.
2. MPG.

BMW stuff is good, but there is better.
Motul Multi ATF proved exceptional in BMW gearboxes, and Redline D4, MT-LV, and MT90 too.
I use D4 in my 6 speed and works like a charm. Unlike BMW fluid, on track does not get too thin where it starts to fade in resistance and with that gets messy with shifting.