So I had to have my transmission replaced at Infinity due to the Synchro not working properly. I have had the transmission now for (+/-) 15K miles. I am going to be changing the transmission fluid and was wondering what everyone recommends? Is OEM the best options to keep these transmissions running smoothly or is changing the viscosity something to consider?

Any advise is greatly appreciated!

 

Don't change the viscosity unless you live in an extremely cold or extremely hot climate. Even then it's not the best idea. Use OEM fluid or Redline MT-85 (my personal favorite). You shouldn't need to change it out at 15k miles anyway but you can go for it if you want.

 

I personally would suggest you stick with OEM in the mean time mainly because you are still within your warranty period.

 

^^ I agree with Mouse, keep the warrenty going.
I however, put in AMSOIL and liked it so far but only put on about 500 miles and then got deployed....
Side note, and might be stupid question as well, but how did you know your syncros were going? Mine are either going or I need to upgrade the CSC to a HD because my upgraded clutch might be putting out too much heat. OEM fluid would get that spongy feeling after 30 min, now I got RBF +600 and it was holding like a champ for 1000 miles....now when I shift seems like it misses or doesn't want to go into gear? More than likely my CSC though.

 

Sounds more like a CSC to me as well. Worn synchros will usually grind when you shift.

And OP, I forgot you were within warranty period as well, so I'd vote OEM rather than Redline like I said earlier.

 

why the hell would u change it at only 15k? u bored?

 

But you could still 'shift'? Because, I want to say it would not go into gear and I didn't force it into gear, once I felt my hand 'vibrate'(would that be the same as grinding?) I would just cycle the clutch and it would go in.

 

So is this a break in flush or something? Why are you changing it so soon?

 

im wondering if op is the cause of the initial trans issue that was replaced

 

It's good to change out the fluid after the break in period.