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Help with 4l60e in Tahoe

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by cpqtim, Feb 11, 2002.

  1. cpqtim

    cpqtim Registered Member

    Aug 25, 2000
    Likes Received:
    Westport Ky.
    I have a 96 Tahoe (also 73 Blazer) and I am having a tranny problem. At this point I hear a whining noise that is timed to engine RPM. It is more pronounced while in gear. Almost sounds like a noise you would hear in an AM radio from ignition noise but I know it is not that. The sound seems to be coming from the tranny and I think it may be a pump or something like that. The truck has 96K on it with about 20K of those towing a 5600lb boat on the highway. I have serviced the tranny every 10 to 15K.

    Will a 4L60e whine when it is going bad? GM rated the towing capacity on this Tahoe at about 5 or 6K. I am considering getting a 4L80e from the junkyard and having it rebuilt. Is this a straight swap over or am I getting into a project with no end in sight?

    Is there any kit than actually beef up the 4L60e to handle the weight I am towing? I plan on someday needing to tow 9000 lbs. When that day came I thought about pulling the engine and putting in a 400 small block and a 400 tranny. What may be involved in doing this conversion? I know I would lose the OD and have some computer bypassing to do but has anyone done this?

    Any thoughts?
    Tim T.
  2. Gold Rush

    Gold Rush 1/2 ton status

    Feb 17, 2000
    Likes Received:
    Why would you want to kill yourself?? 9000lbs with a Tahoe??? If you really need to tow that kind of weight then go out and buy a 1 ton Dually that is perfect for towing that kind of weight. I got rid of my 1/2 ton pickup and bought a dually just because I tow my Blazer and the 1/2 ton was really squirely and unsafe pulling it.


    <a target="_blank" href=http://www.extremeblazer.com>ExtremeBlazer</a>
  3. 89GMCSuburban

    89GMCSuburban 1/2 ton status

    Nov 15, 2001
    Likes Received:
    Thornton, CO
    Or a Suburban... There's really not a way to beef up the 4L60E. The only recommendation would be to use a TCI Truck Rebuild kit in it and put a big cooler with one of those $30 shift hardener switches. That's about you're only option. I'm not sure if the 4L80E uses the same computer, but if you do that, you'll need to mess with the tranny crossmember and drivshafts because the 4L80E is longer than the 4L60E. I'd say, if you're gonna tow 9,000 lbs., find a 3/4 ton Suburban or a crew-cab pickup.

    Red 1989 GMC Suburban SLE V1500 - TBI 350, 700R4 w/ shift kit, Quad-shock front, 31/10.50/15 Pro Comp MT, 4.10 gears, Duals off cat
  4. HarryH3

    HarryH3 1 ton status Author

    May 31, 2000
    Likes Received:
    Georgetown, TX
    Hey Tim, a former Digital/Compaq FSE here. [​IMG] Sounds like front pump whine that you're describing. I had a 700R4 in an '87 K5 that whined from 66K miles until I traded the truck in at 125K miles. But it wasn't loud enough to hear it while driving. I mostly noticed it while idling, with the windows rolled down. The 4L60e is basically a computer controlled version of the 700R4, so it should be possible to beef it up. I've seen ads for Jet Performance, listing beefed 4L60e and 4L80e trannies.

    BTW, if you want to tow 9,000 lbs, a Tahoe isn't the safest way to do it. You can certainly build enough engine to get it moving, but with the short wheelbase any avoidance maneuvers could quickly turn into a really bad case of the tail wagging the dog. [​IMG] I'd suggest that you start looking for a used, late model 3/4-ton Suburban with a 454 under the hood. It will already have the bigger tranny, bigger axles, bigger brakes, etc. [​IMG]

    <font color=black>HarryH3 - '75 K5</font color=black>
    <a target="_blank" href=http://www.angelfire.com/super/ThunderTruck>www.angelfire.com/super/ThunderTruck</a>
    It's a great day to be alive...

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