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Thread: Why do Automatic Gear Shifts Jerk?

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    Senior PakWheeler juadjee's Avatar
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    Default Why do Automatic Gear Shifts Jerk?

    Hi Guys,

    I'd like to get a discussion going on about why Gear Shifts in Automatic Transmission cars Jerk... So we can bring them to a minimum (or a level of our liking) by checking these points.

    I reckon this discussion would not be as applicable to the likes of Prosmatic and Vario cars because they use a different kind of gear shift technology altogether. In conventional automatic gear cars however, this is an issue.

    I want to know what reasons contribute to the amount of jerk when gears shift.

    Understandably the following contribute to it:

    1. The condition of the transmission system itself - how well maintained and little abused it is
    2. Transmission Oil level
    3. How advanced are the fuel burning settings on the vehicle (more advanced will jerk more)


    What I need to know is, what other factors play a part? Do the throttle body and TPS affect the amount of jerk in the shifts?

    Anything else? Your contributions would be appreciated.
    The pain of war cannot exceed the woe of aftermath.

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    Senior PakWheeler fahadsoulsnatcher911's Avatar
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    if also felt this in my terios kid that there is slight jerk with also a sudden lift in the rpm and a push along with it

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    Senior PakWheeler Racerf1's Avatar
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    Auto jerk like you said due to ATF not being changed regularly
    Tranny filter being choked or corrupted (happens in many Hondas and usually the cause of it)
    Torque convertor becoming weak overtime.
    Clutch packs being worn out
    Just like cold, Heat can cause auto trannys to jerk and cause them to break down too hence the use of Tranny Oil Coolers (best thing for an auto tranny)
    etc
    "The value of life can be measured by how many times your soul has been deeply stirred." Soichiro Honda

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    Senior PakWheeler Xulfiqar's Avatar
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    usually happens when you drive an econobox car - drive a large RWD Mercedes Benz - and feel how it shifts, it uses vacuum assisted shifts - to smooth them out at part throttle and easy driving, while on high revs and high accelerator position it will jerk too - and if its an old 5 cyl turbodiesel it may even chirp its tires in the 1-2 shift
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    Senior PakWheeler Xulfiqar's Avatar
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    Quote Originally Posted by Racerf1 View Post
    Auto jerk like you said due to ATF not being changed regularly
    Tranny filter being choked or corrupted (happens in many Hondas and usually the cause of it)
    Torque convertor becoming weak overtime.
    Clutch packs being worn out
    Just like cold, Heat can cause auto trannys to jerk and cause them to break down too hence the use of Tranny Oil Coolers (best thing for an auto tranny)
    etc
    because the design is SO STUPID that you have to open up the entire transmission to change it out.

    harsh engagement is usually caused by dirty accumulators not being able to softly engage/disengage a clutch drum's brakes.
    ZRS - Zulfiqar Racing Systems ..... - professionals at work - at crackwheels.com

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    Senior PakWheeler Racerf1's Avatar
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    Quote Originally Posted by Xulfiqar View Post
    because the design is SO STUPID that you have to open up the entire transmission to change it out.

    harsh engagement is usually caused by dirty accumulators not being able to softly engage/disengage a clutch drum's brakes.
    Yes Agree it is Bad design on Honda's part
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    Senior PakWheeler Racerf1's Avatar
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    Quote Originally Posted by Xulfiqar View Post
    usually happens when you drive an econobox car - drive a large RWD Mercedes Benz - and feel how it shifts, it uses vacuum assisted shifts - to smooth them out at part throttle and easy driving, while on high revs and high accelerator position it will jerk too - and if its an old 5 cyl turbodiesel it may even chirp its tires in the 1-2 shift
    Well it happens in likes of Mercs too even RWD due to small tiny bushes being worn out (they are so tiny, it is amazing how much they jerk, lol!)
    "The value of life can be measured by how many times your soul has been deeply stirred." Soichiro Honda

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    PakWheeler sunhonbun's Avatar
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    well it is said that prosmatec shifting is quite smooth than normal auto cars...i myself own a pros civic 1.8 but once when i drove my friend"s altis2007 ,i found the shifting same as the prosmatec(no jerks)...i dont know why people praise prosmatec so mmuch

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    Senior PakWheeler juadjee's Avatar
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    Quote Originally Posted by Racerf1 View Post
    Auto jerk like you said due to ATF not being changed regularly
    Tranny filter being choked or corrupted (happens in many Hondas and usually the cause of it)
    Torque convertor becoming weak overtime.
    Clutch packs being worn out
    Just like cold, Heat can cause auto trannys to jerk and cause them to break down too hence the use of Tranny Oil Coolers (best thing for an auto tranny)
    etc
    My ATF was changed 13000 kms back, and the manual says inspection at every 20k km and replacement at 40k, so I wasn't really thinking it could be that.

    Plus my shifts were very smooth (except for the first to second) but of late I've been noticing a really bad jerk.

    On another thread VCheng had mentioned something that drew my attention towards the ATF. Let me quote (reply to someone else's post)

    Quote Originally Posted by VCheng View Post
    I would suggest the Mobil 1 75W-90 full synthetic in your car, changed every 75,000 km, but immediately if having driven through deep standing water that floods the engine compartment.
    My car had recently driven through some deep standing water and he recommended me to change it.

    Would you guys agree with that in saying driving through the water is a big contributing factor?
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    Senior PakWheeler juadjee's Avatar
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    How can I check for the Tranny filter and clutch packs? I'm sure my mechanic will make a stupid pan wali dumb founded shakal when I ask him to inspect these. And also shed some light on Tranny oil coolers please? I thought ATF is cooled through the radiator.

    And does the TPS or any other settings on the throttle or accelerator wire (i noticed an adjustment near where it gets attached to the throttle body) have an impact on the jerk?

    My car does not jerk if the gear shifts at higher revs. Its at the lower revs and the jerk is awful, almost as if the car is disengaging and engaging in gear like a M/T i can feel it pull back a bit before it shifts arghh.

    Also please recommend me ATF for Honda 2000 VTi.
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    Senior PakWheeler juadjee's Avatar
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    Quote Originally Posted by sunhonbun View Post
    well it is said that prosmatec shifting is quite smooth than normal auto cars...i myself own a pros civic 1.8 but once when i drove my friend"s altis2007 ,i found the shifting same as the prosmatec(no jerks)...i dont know why people praise prosmatec so mmuch
    Yes sir, as I said in the first post of the thread.. This discussion would not so much be applicable to the newer generation cars which have advanced auto gear shifting technology. And you are right about the altis, even the corolla X has an extremely smooth shift.

    However let's talk about cars that DO jerk - and the factors associated with it.

    Thank you
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    PakWheeler towaseem's Avatar
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    Quote Originally Posted by sunhonbun View Post
    well it is said that prosmatec shifting is quite smooth than normal auto cars...i myself own a pros civic 1.8 but once when i drove my friend"s altis2007 ,i found the shifting same as the prosmatec(no jerks)...i dont know why people praise prosmatec so mmuch
    Brother, We are Pakistanis we believe in rumours rather experience something, I used to have Prosmatic then I bought Liana 1.6 Eminent, now 1.6 Toyota Auto. Honestly speaking Liana pick and shifting was quicker and smoother than Honda, Corolla. But Liana has bad name and 90% those people said flop car who never drove Liana or even sit in that..

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    Retired VCheng's Avatar
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    Quote Originally Posted by juadjee View Post
    How can I check for the Tranny filter and clutch packs? I'm sure my mechanic will make a stupid pan wali dumb founded shakal when I ask him to inspect these. And also shed some light on Tranny oil coolers please? I thought ATF is cooled through the radiator.

    And does the TPS or any other settings on the throttle or accelerator wire (i noticed an adjustment near where it gets attached to the throttle body) have an impact on the jerk?

    My car does not jerk if the gear shifts at higher revs. Its at the lower revs and the jerk is awful, almost as if the car is disengaging and engaging in gear like a M/T i can feel it pull back a bit before it shifts arghh.

    Also please recommend me ATF for Honda 2000 VTi.
    To properly check clutch packs, an approved scan tool is need to look at CVI (clutch Volume Indices) in real time as the car is being driven.

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    PakWheeler xain91's Avatar
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    Quote Originally Posted by juadjee View Post
    How can I check for the Tranny filter and clutch packs? I'm sure my mechanic will make a stupid pan wali dumb founded shakal when I ask him to inspect these. And also shed some light on Tranny oil coolers please? I thought ATF is cooled through the radiator.

    And does the TPS or any other settings on the throttle or accelerator wire (i noticed an adjustment near where it gets attached to the throttle body) have an impact on the jerk?

    My car does not jerk if the gear shifts at higher revs. Its at the lower revs and the jerk is awful, almost as if the car is disengaging and engaging in gear like a M/T i can feel it pull back a bit before it shifts arghh.

    Also please recommend me ATF for Honda 2000 VTi.
    i guess the pan or locally called gear chamber is washed with petrol to remove minute metal particles whenever ATF is changed as there is no filter in old cars. i used to do same with my Toyota Platz/Echo and it performed great. yes! the jerk is slightly more noticeable if gear shifts at lower rpm.
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    Senior PakWheeler Xulfiqar's Avatar
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    to do a standard transmission pressure check - you need a high pressure hydraulic gauge set with different size adapters to check different clutch actuation pressures.. If you see pressure but no engagement or weak engagement, open up transmission, if you dont see pressure - its either a solenoid or valvebody problem.

    About jerking - every transmission will jerk at high rpms - or the fluid will severly heat with slipping clutches and torque convertor swishing the fluid mad. At low rpms the transmission is spinning slowly and the convertor is not stalled giving an elastic drive saving everything - in this case the transmission CAN be equipped to shift softly.

    the older ECT Aisin (Toyota) transmissions shift by solenoid actuation but have a pressure control cable too to fine tune shift aggression.
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    Senior PakWheeler juadjee's Avatar
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    Right.. So nothing for the laymen :p
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    Senior PakWheeler Racerf1's Avatar
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    Quote Originally Posted by juadjee View Post
    My ATF was changed 13000 kms back, and the manual says inspection at every 20k km and replacement at 40k, so I wasn't really thinking it could be that.

    Plus my shifts were very smooth (except for the first to second) but of late I've been noticing a really bad jerk.

    On another thread VCheng had mentioned something that drew my attention towards the ATF. Let me quote (reply to someone else's post)



    My car had recently driven through some deep standing water and he recommended me to change it.

    Would you guys agree with that in saying driving through the water is a big contributing factor?
    I do not know to what was Bro @Vcheng was replying to but I am assuming it would be to manual transmission not a auto. In Auto's Dexron ATF is used but in Honda, Dexron ATF is not recommended it will surely mess up your tranny over time. Honda Trannys are very sensitive to what oil you use. example in MT gear you can use motor oil also but normal gear oil is not recommended only Honda MTF.

    So check with @Vcheng as he is a very learned man and give me the link to the post so i can try to understand the whole thing
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    Senior PakWheeler juadjee's Avatar
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    Quote Originally Posted by Racerf1 View Post
    I do not know to what was Bro @Vcheng was replying to but I am assuming it would be to manual transmission not a auto. In Auto's Dexron ATF is used but in Honda, Dexron ATF is not recommended it will surely mess up your tranny over time. Honda Trannys are very sensitive to what oil you use. example in MT gear you can use motor oil also but normal gear oil is not recommended only Honda MTF.

    So check with @Vcheng as he is a very learned man and give me the link to the post so i can try to understand the whole thing
    Yes, that response is in reply to someone else's message and he is recommending a MTF to him. I quoted it here to reaffirm the point whether driving through standing water really makes your car need an immediate transmission oil change, and if that is the reason my car's been jerking.

    Thanks.
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    My Toyota corolla axio dont jerks but my honda civic 08 jerks.Its due to quality of tranny.Jerking causes incomfortability in driving and its irritation when changes gears constantly.
    Aunda Fan

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    PakWheeler libra3's Avatar
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    change the transmission oil and put good transmission oil and u see the results. the jerk become very less.

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