Knocking from rear of car on shift

frozen

1 AYC Bar
Lifetime Member
Location
Queensland
First Name
Josh
Drive
1990 Mitsubishi GTO
Formerly: 1996 Galant VR-4
Just been noticing it, a knocking coming from the rear of the car, sounds like the main drive shaft coming from the front taking up slack and knocking as it puts power to the back - thats the best description of how it sounds i can give..
Just when i drop the clutch into the next gear while applying power.. even if i just clutch in, rev a bit as i quickly take out the clutch it will do it.

You can REALLY hear it if i do a launch and spin all 4.. like a knock knock knock knock kinda sound, where as usually its just 1 knock, if the car judders its multiple..

Ill attach a recording i took on my phone. Save it rather than open it, then change it from .pdf to .wav to hear it (wouldnt let me upload a sound file..)

You'll notice one knock near the end, followed by 2-3 knocks when i do it again but a bit harder. The phone was sitting on the rear seat.

also note this is in 4th going around the speed limit.. so not really flogging it, just applying power as i take out the clutch.
 

Attachments

  • Sound clip 11.pdf
    368 KB · Views: 16

bradc

1 AYC Bar
Location
New Zealand
First Name
Brad
Drive
Facelift Manual 400hp VR-4 Legnum
Can you feel any vibration at all coming through the car at any speed? I wonder if the rubbers in the driveshaft mounts are a bit tired.
 

frozen

1 AYC Bar
Lifetime Member
Location
Queensland
First Name
Josh
Drive
1990 Mitsubishi GTO
Formerly: 1996 Galant VR-4
theres always been vibration :p unless you mean a different kind? how would i check.
 

bradc

1 AYC Bar
Location
New Zealand
First Name
Brad
Drive
Facelift Manual 400hp VR-4 Legnum
Get underneath the car and wiggle the driveshaft near the rubbers and inspect them for damage.
 
G

Guest

Unregistered
rear diff mount rubbers?

also cheak for play in the diff, how far does it spin before you fell the gears engage and turn the wheels?
 

frozen

1 AYC Bar
Lifetime Member
Location
Queensland
First Name
Josh
Drive
1990 Mitsubishi GTO
Formerly: 1996 Galant VR-4
the diff has just been rebuilt (as in had a couple new bearings etc before it went on the car) as it is a S-AYC from an evo 8..

Ill have a look over the next couple days for play and mount rubbers. where would i look for the mount rubbers?
 
G

Guest

Unregistered
the rubbers are in the in the the legs that connect the diff to the sub frame.
there a pain to change because afaik the sub-frame needs to be dropped to get the bolt out.

its on my list of things to do, and I'm yet to find a kit or suitible replacement bush
 
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