Drivetrain 89 GT Transmission knocking

FetusLasVegas

Member
Sep 19, 2018
78
4
18
Chicago
Driving today, all of a sudden my trans is knocking with the clutch disengaged under deceleration and with the clutch engaged at any time while the car is moving. The knocking seems to increase with speed. Stock t-5. Thanks for any help!!
 
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Let me fix that sentence for ya....."WAS a stock t-5"....lol. Does it sound like one of those machines that pops lottery balls randomly in the air from various locations? Or is it a single rhythmic thumping? What does it sound like sitting still with the engine running and out of gear, no clutch pressed? And finally, sitting still with engine running out of gear with clutch pressed? Trying to cover all the questions I'd check in person.
 
It’s not really a thumping. More of a knock or schlap... intermittently rhythmic if that makes any sense? Out of gear, stopped, no clutch, no sound. Sitting with clutch pressed, no sound. It’s only while moving with the clutch in, or under deceleration in gear with clutch out. Hope that helps.
 
Potentially a driveshaft universal joint. Let some others come in and reply. I'm sure we can figure this out. Till then, reach under the car and see if you can move the driveshaft and check for free movement.
 
Update, payed good attention on the way home. Definitely a speed sensitive knock. It only happens while moving with no throttle input, or while the clutch is engaged while moving. I’ll get under the car and check the driveshaft in the morning.
 
Got under the car and twisted and shook the driveshaft with parking brake on and car in first gear. there is a little bit of play while twisting. Maybe ¼” max. When shaking the shaft side to side about the same. Can’t really tell if the play is in the u joints or the tail shaft.