• First high torque N54 (335i/135i) steptronic transmission build completed by Level 10 Transmisisons - ~700 pound-feet capable

      As many of you know, BimmerBoost user LostMarine got his 335i Steptronic transmission built by Level 10 to handle increased torque as his upgraded turbos took their toll on the stock transmission. Turn around time was surprisingly quick and should be 10 days and under for all N54 transmission builds. LostMarine had the transmission built along with upgrading the torque converter with a higher stall and the valve body. Price will vary depending on options.

      In Lost Marine's words:

      So here are the details I can speak of. Car runs strong, very solid and strong now. Much improved over what I can remember even when I first bought the car. Here she is as the short journey began. Luckily the car was only down for about 1-1/2 weeks

      Clutches were fried in mine as you can see from this pic.

      They were replaced with stronger material obviously. Now rated up to 700ft/lbs

      Tq convertor was setup for mild street use and increased stall RPM by 500.

      Sorry no more pics on that

      VB Pressure was increased from the stock 60-70psi to 130 psi.

      Pump volume was also increased in total flow from 2qt's/30 seconds to 3 qt's/30 second

      All of this translates in the much stronger and firmer shifting that I have been noticing.

      I have to say, for being a BMW and asking for a mild street use Transmission , Level 10 Delivers.

      The higher stall has nearly no affect on the DD driving characteristics of the car. I do not feel any "slack", and had i not known the stall was increased, I could never tell.

      I had planned on attaching video of the car/trans going through the gears, but the angle was way off. I attempted to have it catch the sound and speedo/Tach so you could see the correlation, along with Datalogs. The roads today were not easily manuevered though.

      This article was originally published in forum thread: First high torque N54 (335i/135i) steptronic transmission build completed by Level 10 Transmisisons - ~700 pound-feet capable started by Sticky View original post
      Comments 64 Comments
      1. klipseracer's Avatar
        klipseracer -
        Does the X5 not use the same transmission as the 335ix? And aren't the X5 35's N55? I do see that the N54 was hooked up to the F01 740i. Not sure if the transmission is different though.
      1. alex@ABRhouston's Avatar
        alex@ABRhouston -
        whoops- typo my bad. X6!

        X5 only came with N55.

        but NG6 engines in general all look the same when you see a transmission like that... so that could have come out of a 3.0 N52 as well.
      1. Tamut's Avatar
        Tamut -
        Videos are not live any longer?
        didnt have a chance to catch them Click here to enlarge
      1. NniftyFour's Avatar
        NniftyFour -
        Me either. Repost!
        Now someone else has to chime in, but I think these original level 10 transmissions really needed custom TCU software to work properly. Now that we have the Alpina tune might these upgraded trans. fair better?

        Also if your gonna push big numbers its better to use a flash based tune. Using a flash based tune allows the TCU to see the higher load numbers from the ECU and be better equipped to handle the shift. DCT guys saw a big improvement when they ditched the piggyback (or at least ran a backend flash) These trans. do read engine parameters over CAN to help determine how they're gonna shift and don't see the true picture with piggybacks.

        P.S. not that I don't love JB4. JB4 is great for a basic bolt on setup. But IMO if you can take advantage of the comprehensive integration BMW designed into these cars then why wouldn't you. (Now we can with BBflash)