I know most of you guys use AC Delco fluid.
I changed mine this March and have put another 10k miles on it (a lot of hwy commute)

My question is:
How often (what milage interval) do you guys change the tranny fluid?

 

I think MT tranny fluid is every 30k miles?

 

^correct.
every 30K

 

IIRC, the MID will tell you when to change it. I think anytime a 3 pops up, that's when it's recommended to be changed.

I've been switching mine out around the 30k mark. I'm not sure what other members are doing so I'm sure someone else will chime in.

 

25-30K miles sounds right.

 

0-60k miles is your first then like everyone said every 30k miles change it

 

in case anybody wants a different example, i did my first at 40K, then 80K, and i'll do my next at about 120K miles. I haven't noticed any real degradation.

 

30k

 

My car had it done at 45k right before I bought it, when the dealership rebuilt my 3rd gear synchros. Dealership put in Honda fluid obviously.

At 65K I replaced it with GM Synchromesh and noticed a huge improvement. There was also a ton of gold dust in the old fluid. (20K interval)
At 80K a year later I noticed a slight degradation of shift quality, so I replaced with GM Synchromesh again, well ahead of schedule. (15K interval)

These intervals are probably overkill, but I don't mind the labor of changing it, and the fluid is only ~$30 depending where you find it. My car sees a lot of short trips on very cold mornings in the winter, where the trans fluid probably never gets up to temp. My uneducated guess is that operating at very low temps makes the fluid shear more quickly.

If you don't mind getting your hands a little dirty, and you can find the fluid for cheap, I don't see any reason not to do a drain/fill after every winter.

 

I change it if/when I start experience irregular notchy shifting on my cars. Though the TL is quite a PITA to do relative to my Civic & CRX.

 

This is debris from your synchronizers.

 

Yep. It was almost nonexistent the second time around. I'd attribute it to double-clutching 100% of my downshifts since the drain/fill, along with better lubrication from the GM fluid versus Honda's stuff. And of course, a slightly shorter interval.

 

Yep. Doubling clutching downshifts will result in a huge reduction of material loss from synchronizers. Initially, there is going to be some when they are new... that is to be expected. But once the mating surfaces have been "married", you will get very little debris floating around in your box when you double clutch.

 

i always thought you don't need to change the tranny fluid for any MT cars, as i was told by my mechanic. never changed in my last car which had 110k miles. runs n feels fine

 

all fluid wears. or in other words, loses its efficiency

 

Yup ^ I switched to GM SM at 27k and will probably change again at 50k or so.