locking down the downshift lever?

Engine, Transmission & Driveline

  1. WissaMan

    WissaMan Member

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    When I was a teenager, on my 68 New Yorker I strapped the downshift lever down so that it was always in the WOT position. I did this so it would give me maximum shift pressure at all times (or so I thought back in the day) and delay upshifts even under light throttle

    It seemed to do what I wanted, but was this a wise thing to do? But now that I'm older I am wondering if that is bad for the long term health of the transmission?
     
    Last edited: Oct 27, 2019
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  2. Davea Lux

    Davea Lux Senior Member FCBO Gold Member

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    Sooner or later, probably sooner, it would kill the transmission because it is not designed to operate that way full time. Probably not very healthy for the engine either as it would likely be over reving.

    Dave
     
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  3. CBODY67

    CBODY67 Senior Member

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    I'd suspect that your "backdoor hack" might have raised the line pressure a bit for firmer shifts at all times. But the TFs were already known for firm up and down shifts already, so were you trying to reap the benefits of a shift kit without having to install one?

    It seems that the recent GM 4L60E family has a high-mileage issue where the pressure-determining solenoid fails and puts full line pressure into the unit. Usually after it has been in operation for an hour, from my observations. I had TWO Impalas that had this issue, once past about 150K miles.

    I figured out what it was doing, so I didn't use a lot of throttle in normal driving. Once it was in OD on the highway, no problems. But on the 2005, it ended up cracking the flywheel, due to some stretch of the flywheel-to-torque converter bolts. Stretch that was not discovered until warranty had paid to replace TWO of them, plus having to buy a new GM Reman torque converter (which is a story in itself!). When it was in for another drivability issue, the tech got all bothered that the trans was going out. I told him to worry about the engine, I'd worry about the trans.

    Problem was that to do the solenoid was about a 5 hour job, although the solenoids were not that expensive. I'd planned on getting that done, someday, but since they allegedly knew more about them than little 'ole me did, I opted for the GM Reman transaxle. 100K warranty, too. More of the car is under parts warranty now, for what it's worth. I've spent far too much money on a car with such a low resale value! But it's a durable car, otherwise, now with 225K on it. Starting to investigate an off-lease 300 for when I finally retire, or a lowered short wide single cab Ram Hemi?

    Enjoy!
    CBODY67
     
  4. WissaMan

    WissaMan Member

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    Actually the trans did have a shift kit in it which I installed, but I can't remember if it was before or after my hack. (This was about 30 years ago!) I don't even remember exactly why I did it. I thought it was for the above mentioned reason, but as I think about it, I may have done it originally because the kickdown linkage was missing and I only later realized it also had the side effect of firmer shifts.

    I put 10 ~ 15k miles on it with that arrangement with lots of lead-footed driving. I don't remember noticing any degradation in the transmission operation during that time. I also had an external trans oil cooler mounted which helped.
     
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  5. stubs300

    stubs300 Senior Member

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    There's always that one person!