Thread: Tranny knocks when shifted to gear

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  1. #1 Tranny knocks when shifted to gear 
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    Hi!
    i have a 1995 GP 3.1L
    for the last 3-4 months, when the engine is cold, the tranny make a one time "knock" every time it's shifted from P or N to D or R (especially to R...) (and the engine is "moving" a bit).
    i have changed oil & filter but nada.
    however, when the engine is at working temp. (or even less) the knock is disappeared.
    the tranny has been rebuilt approx. 90K miles ago.
    any ideas?
    thx ahead.
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  2. #2 Re: Tranny knocks when shifted to gear 
    GTX Level Member 02BlueGT's Avatar
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    Check your mounts, the sound may just be from it moving around when you shift, the engine moves most in the park to reverse change, and next most is in the drive to reverse change
    2002 GT...CAI, Headers, Special Eddition two-tone leather interior added, HUD added, 12" Brake Upgrade, ZZP strut tower bars, gmpp sway bars, poly motor mounts, -6an braided SS fuel hoses , Hptuned, Headers, Top Swaped, 50lb inj, E85, 3.4
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  3. #3 Re: Tranny knocks when shifted to gear 
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    thanks!
    i have replaced the bottom mount and the 2 front mounts (only the big ones, without the "forks").
    is there anymore mounts somewhere???
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  4. #4 Re: Tranny knocks when shifted to gear 
    GTX Level Member 02BlueGT's Avatar
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    My car has two lower, and two upper(torque straps), but I don't know how the 95 3.1 was setup, someone else will need to chime in for that answer
    2002 GT...CAI, Headers, Special Eddition two-tone leather interior added, HUD added, 12" Brake Upgrade, ZZP strut tower bars, gmpp sway bars, poly motor mounts, -6an braided SS fuel hoses , Hptuned, Headers, Top Swaped, 50lb inj, E85, 3.4
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  5. #5 Re: Tranny knocks when shifted to gear 
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    so could it be just a faulty engine mount? nothing in the tranny?
    (i really don`t want to rebuild it again...)
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  6. #6 Re: Tranny knocks when shifted to gear 
    Transmission Expert Trannyman95's Avatar
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    It is possible as there is a lower engine mount in addition to the lower trans mount. You are likely getting this clunk when cold because the engine idle rpm is higher and also when the trans is cold and the fluid is cold and a bit thicker the pressure is a little higher also which will cause a slightly firmer engagement. Also check all of your exhaust system and exhaust hangers to make sure it is supported properly and not causing the noise as the engine will rock back and forth quite a bit when going in and out of gear. You may try having someone else sit in the car and go back and forth between reverse and drive while you have your head under the hood trying to isolate where the noise is really coming from.
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  7. #7 Re: Tranny knocks when shifted to gear 
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    i have replaced all engine mounts. still there is this knock while the engine is cold.
    could be a rpm problem? I've noticed it's taking longer period to reduce to idle rpm when engine is cold...
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  8. #8 Re: Tranny knocks when shifted to gear 
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    Hi!
    I have noticed on my other car that even on 2000 rpm when i shift the gear the rpm is reduced and there is no knock sound.
    is there any mechanism to do so on the GP?
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  9. #9 Re: Tranny knocks when shifted to gear 
    Transmission Expert Trannyman95's Avatar
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    It may be excessive slop in the geartrain inside the trans or even a sticky valve in the valve body causing higher line pressure initially until it cycles. Up until 96/97 year the 4T60E did have a common problem of the drive shell inside the trans wearing and even stripping or coming apart and this will cause noise and eventually wear bad enough to break and will make a lot of noise and lose reverse. There is really no way to know this except for tearing the trans apart. Also you should check over all of the suspension components in the front end to make sure you arent getting noise from that. Have you tried having someone else sit in the car and cycle it through the gears and load the engine as I suggested in my last past to see if you can hear exactly where the noise is?
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  10. #10 Re: Tranny knocks when shifted to gear 
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    Hi Trannyman95!
    what happens when the engine is cold and then shifting into gear is that the entire engine moves a few inches to the front or to the rear depending on what the gear is shifted to.
    the noise is apparently from the engine movement and not from the tranny itself.
    on the last tranny oil and filter change (last week) i haven't noticed any debris other then the regular "metal powder" on the magnet.
    now I'm confused; all of the mounts are new. what's next???
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  11. #11 Re: Tranny knocks when shifted to gear 
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    The movement is normal and just the nature of a fwd vehicle that has the engine suspended with all rubber mounts. This is a reason I suggested checking all of the exhaust system to assure the hangers are all attached or in good shape because the engine is going to rock a bit forward and backward and anything attached moves with it. Even though your trans pan looked clean doesnt mean things are wearing inside and causing excessive slop which again you wont know without a teardown. Any front suspension component that is going bad can also cause clunk noises when going in and out of gear.
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