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Thread: E39 Differential question for an LS swap

  1. #1
    Join Date
    Feb 2019
    Location
    Central VA
    Posts
    8
    My Cars
    1999 528i

    E39 Differential question for an LS swap

    Iím embarking on an LS/CD009 swap in a 99 528iT with a factory auto. And am trying to tighten up my budget numbers.

    To save a few hundred bucks getting it running Iím thinking of swapping in a 540i diff and half shafts now to prep for future LSD. My thinking is that I donít want to buy 2 driveshafts, and if I want a large case LSD later (and accompanying beefier half shafts), Iíll spare myself that cost. Itíll also be advantageous in terms of gearing to drop from my factory 4.10 to a 3.15 or even 2.93 with the ratios of the CD009.

    Power goals are a moving target still. Part of me wants to go turbo out of the gates to avoid fabbing 2 exhaust systems. Absolute max would be 450-500 whp. Iíve seen mixed reviews of failure rate at these power levels for a stock 528 diff.

    My questions are: am I missing anything? Will I have to rework my driveshaft if I later choose to go from 540 to M5 diff? Or should I just get an insert from Team M Factory?

    All of the help is appreciated. Iíve poured over these forums for the last few months and have gotten a ton of great information.

    Thanks


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  2. #2
    Join Date
    Jul 2009
    Location
    Washington
    Posts
    177
    My Cars
    BMW 525i
    I'll tell you what I'm going to do but its no means the best route. I'm going to get a 540 dif and later install a limited slip. My reasoning was M5 difs are about 1000 on ebay and probably need to be rebuilt. I'm not interested in investing more time to find one cheaper or have to rebuild it. I would rather install a wavetrac or similar unit. Preferably after talking to someone local that has done the swap.

    At least with the 540 dif you can continue your swap and drive it without worrying about it now and spending the money.

  3. #3
    Join Date
    Feb 2019
    Location
    Central VA
    Posts
    8
    My Cars
    1999 528i
    Thatís basically where I am. My project is going to be a long haul even if everything goes well so maybe a diff pops up on my radar in the meantime but 540s are plentiful and cheap if that doesnít happen. At this point Iíd rather spend that $1k on a control arm overhaul, big brakes, or coil overs.


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  4. #4
    Join Date
    Jun 2011
    Location
    Elizabethtown, PA
    Posts
    1,420
    My Cars
    99 540i6
    The M5 diff is longer, I can't remembeer how much, but if you give some extra room with your 540i diff driveshaft it will still fit. If I recall correctly it's about 1.25 inches.

    - - - Updated - - -

    I did e46 M3 3.62 gears in mine with new clutches and bearings, it wasn't too bad to do. I'd probably be OK with the stock 3.15's though too. Sometimes I wish I wouldn't have switched.

  5. #5
    Join Date
    Feb 2019
    Location
    Central VA
    Posts
    8
    My Cars
    1999 528i
    Thanks for that info. I read over your very well detailed build thread and subsequent wiring info posts several times. Your build is one of the ones that led me to believe I could tackle one myself.

  6. #6
    Join Date
    Jun 2011
    Location
    Elizabethtown, PA
    Posts
    1,420
    My Cars
    99 540i6
    Quote Originally Posted by CvilleTallman View Post
    Thanks for that info. I read over your very well detailed build thread and subsequent wiring info posts several times. Your build is one of the ones that led me to believe I could tackle one myself.
    Cool! Good luck!

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