It was time to service my manual transmission, shifts were notchy and crunchy and at times I had trouble putting it into first gear and reverse. I wanted to put new fluid in as soon as possible that would replace the degraded fluid and would help clean out the system before I put expensive BMW fluid in. After doing some research on forums and reading I settled on synchromax from Royal Purple. I wrote an email to customer service at Royal Purple confirming that it would be appropriate for an E90 335 manual (and it was). I bought two new plugs, drain and fill for the fluid service and off I went. After getting it done the change in the feel was night and day, as of today I have had it in the car for just over 2,000 km and the smoothness is fantastic. It has made the car feel so much better. I am planning to put the BMW fluid in the vehicle in a month or so after the synchromax has had its chance to work it way into the gearbox and clean out the 98,000 km of grime in there, since the fluid had clearly never been changed before.
Changing out the manual fluid in your E90 or in any car is something I cannot stress enough. Not only for the reason of preventative maintenance and extending the life of your transmission but for the every day feel of your gearbox. Based on how cheap this service is ($20 CAD per bottle of synchromax, you need two quarts) I am definitely adding this on the list of annual spring service no matter how many miles I put on the car; the smooth buttery shifts are worth it to me.
