4L60E rebuild help

Discussion in 'Transmissions' started by Morten, Nov 30, 2020.

  1. Morten

    Morten Newbie

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    Hi all, I have a tahoe 96 5.7 with the 4L60E, last year I had a 2rd to 3rd 2-300rpm shift flare, I put in a corvette servo and it helped with the flare, but now when in 4th and light throttle it revs up and holds or looses speed until about 3-3500rpm then downshift to 3rd and moves fine again, so guess the 3rd/4th clutch pack is gone, the oil is pure red and does not smell burnt, the apply band moves in about 0,15", no codes, lockup is also working. The truck has about 170000miles on it, and from what I know never rebuild. I live in europe so parts are a little more work to get, and it's winter so it will be some months before I start but would like to hear what would be good to do with it, so have time to get the parts.

    I have not done a automatic transmission before, but I should be ok with it.

    First, is it just a rebuild or do you have any ideas to try before that?

    If a rebuild - is there any kit that is just the right one to get?

    I would like a firm shift, but nothing thats hard on the truck.

    Any help is appreciated.


    Regards Morten
     
  2. Schurkey

    Schurkey I'm Awesome

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    Surprising. The "Corvette" servo applies the 2--4 band in second gear, releases in 3rd. I'd think a flare going into third would be more likely the 3--4 clutch, or the 2--4 band RELEASING too quickly.

    The 3--4 clutch is engaged in both 3 and 4. If it failed, you'd lose both gears, not just 4th.

    If the 2--4 band was weak/worn, or the part of the servo assembly that controls band application in 4th gear--which is not the same as the part of the servo assembly that engages for 2nd gear--is weak, 4th gear would be crippled.

    "I" would pull the servo out of the case for inspection. This can be done without disturbing the rest of the trans, so it should be pretty easy..

    If there was ANY HINT of problem engaging 1st gear, I'd replace the 1--4 shift solenoid.

    I suppose you could have a broken accumulator for 4th gear also...but I don't have any experience there.

    How old is the trans filter?
     
  3. Dropped88

    Dropped88 I'm Awesome

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    Could have a cracked accumulator piston most are plastic. But also could be band being its flaring in 4th so its alsoprobably about burned up cause the band can barely handle in slippage before its gone.
     
  4. Supercharged111

    Supercharged111 I'm Awesome

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  5. thegawd

    thegawd I'm More Awesome!

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    What is the definition of "trans flare?" Could this be related to a faulty tps? Easy to test and replace... Al
     
  6. Morten

    Morten Newbie

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    Hi, thanks for your answer.

    I read somewhere that the 2-4 servo also acts as accumulator for 3rd so the corvette servo was also to adress the 2-3 flare? - it helped in my case.

    I got the truck 3 1/2 year ago and I have about 3000miles on it, I guess I will take out the servo and check, when I installed it I pulled out the o-ring and cut it and pulled the servo out, the new servo came with new o-ring/seals - is it possible to just stretch the o-ring so I can pull the cover and reuse?

    Only problem in 4th, I drive the truck very light, 85% of the time it never gets in 4th.

    Transfilter, properly never been changed.

    Regards Morten
     
  7. Schurkey

    Schurkey I'm Awesome

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    The servo may act as an accumulator. I don't know. Gonna have to read up on that.

    Around here, I'd say you should just buy another O-ring. I suppose that's not so easy where you are.
     
  8. Morten

    Morten Newbie

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    Could it be as simple as a clogged filter?
    I will take my chance on reusing the o-ring, otherwise I don't need to drive my truck so it can stay as long as needed.

    Could it be as simple as a clogged filter?

    Broken accumulator for 4th gear - can that be done without pulling the transmission?


    Regards Morten
     
  9. Morten

    Morten Newbie

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    Found this about the servo acts as accumulator.

    upload_2020-12-14_20-16-22.png
     
  10. Schurkey

    Schurkey I'm Awesome

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    I have a Trailblazer with a 4L60E. Currently 250K miles.

    For perhaps ten years, it's been slow to engage Reverse when the temperature drops in the winter. Spring, summer, fall--works perfectly. When the temp gets to or below freezing, it's slow going into reverse first thing in the morning. The colder it gets, the longer it takes to get Reverse. Once the trans warms up, it's fine.

    I ignored this for years because a local trans shop thought "maybe" it was a warped valve body, distorted when the cold contracted the aluminum. They didn't seem to have any certainty about it; and once the trans warmed up, it worked just fine.

    I started getting a 1--2 flare last summer. Not always, and not real bad. I figured the trans was toast, at a quarter-million miles it wouldn't be too surprising to have genuine problems. But a fluid flush and pan-drop seemed like a first-step in the repair. Last fall, I flushed the fluid and installed a new filter.

    PROBLEMS SOLVED. No more flare, no more delayed reverse. (although it has yet to get genuinely cold, but at least so far there's no trace of delay going into reverse, and it's well below freezing now.)

    Point being...a fresh filter and new fluid can--sometimes--work miracles.

    You should see where the accumulator is for 4th gear. You might have to drop the pan and pull the auxiliary valve body, or even the main valve body--but I wouldn't expect you'd have to pull the entire transmission.
     

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