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4L60E or T56

This is a discussion on 4L60E or T56 within the Drivetrain forums, part of the LSx Technical Help Section category; honestly how much does the t56 out perform the 4L60E i have a 2 trans ams one with each and ...

  1. #1
    Junior Member
    Join Date
    Feb 2007
    vivian, la

    1999 Trans Am

    4L60E or T56

    honestly how much does the t56 out perform the 4L60E i have a 2 trans ams one with each and both have there benifits, don't get me wrong the t56 is alot quicker to 100 but the 4L60E is pretty solid all the way through

  2. #2
    Junior Member SkreaminHawk's Avatar
    Join Date
    Sep 2005
    Fredericksburg, VA

    2000 T/A Firehawk

    What you're doing is comparing apples to oranges. What are you looking to do with it? The automatic you can build with a nice size stall and transbrake (depending on the size of your cam is when you'll want to decide how big of a stall you want to go with). This is based on the powerband of how much power you develop, and where at, in the RPM range, that it develops. With that being said, a factory automatic is alot smoother (and crisper) on the factory 10 bolt rear. I, personally, have seen factory 10 bolts well into the 11s, without even popping the differential cover off, for mods to upgrade.

    The Tremec 6 speed on the other hand (which is what I have dealt with my past 2 f-bodys), will use and abuse the 10 bolt. On my WS6, I shattered it in the first week. With my firehawk, I was already on my 3rd one. The red one being stock, the firehawk definately not. No need to go into detail, because as most on the board will tell you, if you have the T56, and you plan on doing any extensive work to your car, you may as well spend the money and buy the 12 bolt or Ford 9-inch. Its JUST THAT SIMPLE!

    Drag racing, your better off with an automatic. You will NEVER shift faster than an automatic with a shift kit... PERIOD! However, if you're like me, and just want to have the bragging rights of being able to beat automatics (half the reason being because you have more money in mods into the car), and you like rolling through the gears on the highway, get the 6 speed. And there you go


  3. #3
    Junior Member
    Join Date
    Feb 2007
    vivian, la

    1999 Trans Am

    appreciate it, i've just always heard about how much the t56 out performs the 4L60E

  4. #4
    Moderator Firebirdjones's Avatar
    Join Date
    May 2006
    They do perform a little better, mainly due to a couple things. The manual robs less HP and the other reason most people don't consider is the fact that the manual has a better gear spread 1st through 4th that keeps the engine happy. The only thing the sucks about the 6 speed is the 2.66 1st gear and the factory 3.42 rear gears. Gives you an affective gear ratio of 9.09 which isn't that great,,,but once rolling the gear spread is decent. A set of 4.10 gears cures that initial problem.

    The auto 4L60E is kind of a sucky transmission for any type of drag racing simply because the gear spread stinks. One advantage it has over the 6 speed is the effective gear ratio in 1st. With a 3.06 first gear and a 3.23 rear gear,,,you get an affective gear ratio of 9.88,,,which helps the car snap out of the hole pretty quick,,,but then comes the 1-2 shift and things go down hill from there. The gear spread and RPM drop on the 4L60E from the 1-2 shift is terrible and has not been a favorite among serious drag racers. If you want to do any serious drag racing the overdrive is not a good choice,,go for a glide or 3 speed auto. Couple that with the fact that the Auto will rob a little more HP,,,,then you begin to see why the 6 speed cars stock for stock tend to be a little quicker,,,but the margine is so small it would take an experienced stick driver to take advantage of it. Larry.

  5. #5
    Nitrous Tuner LS2Tuner's Avatar
    Join Date
    Aug 2006
    WestCoast AZ-CALI

    05 Goat SMASHED

    There is NO subsitute for dumping the clutch. I would say on a average just to throw a # out there I'd say 2-4 tenths depending on the driver.
    Plus the rear ratio is different most of the time from the factory so it's hard to compare the two evenly.

    I'll vote for the T-56.
    Don't be afraid of the bottle!!! Be afraid of your tune!!!

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