I have a mellow knock, (I wouldnt call it a bang) that seems to be coming from around the front of my transmission (sound comes from behind the radio). It happens sometimes when I put it in gear, either to reverse or drive from either park or nuetral. It also happens occasionally on upshifts, most noticable on 2-3 upshift. If I am "coasting" with my foot off the gas at around 20 mph, and I apply the gas in any fashion other than grandma-ish, it makes the sound as the transmission "engages" and starts accelerating the car from a coast. (does that make sense?)

I have a new poly tranny mount, new poly torque arm bushing, i've tightened the torque converter bolts the best I could, and i've looked under there while my dad ran it through the gears and nothing is hanging or banging around. its not the exhaust or something stupid like that hitting, its definitely drivetrain. What could be causing this? Driveshaft has some play in it with the tranny in nuetral (worn rear) but I am 99% sure this is coming from the foward portion of the car. I realize that because of the way human hearing works it is difficult to tell whether sounds are coming from in front of you or behind you. I had somebody ride in the passenger seat and look out the driver window and they confirmed it is coming from the foward portion of the car.

It also happens if I am accellerating and take my foot completely off the gas. If I am at a stop with my foot on the brake and in drive and I pop it up into nuetral it will sometimes do it as well.

 

Anybody?

 

Check your universal joints, how much play is in your drive shaft? Check the motor to trany mounts as well. My guess would be the u joints, or maybe the front and rear seal in your trany.

Try getting under the car with it up on a lift or stands and have someone put in into gear and trace the sound that way.

 

U joints are new. Its been awhile since I was under there, but I want to say there is maybe 1/6th of a turn of play in the driveshaft off the top of my head. How much should there be for a non posi 2.73 10 bolt? Car just turned 170k this morning, and it's probably the original rear.

 

check the T/C to flywheel bolts..mine came loose and it sounded like my engine was knocking really really bad.


oops nvm...realized you already tried that.


How about the starter?..friend had a mustang that the starter drive would tap the flywheel when moving b/c it had come loose...sounded like knock and was very audible.

 

It's definitely drivetrain because of the way the noise coincides with engine/transmission operation. It's as if anytime the car goes from putting torque from the engine to the wheels to the wheels putting torque back up to the engine, like engine braking.

On a somewhat related note - for those of you who have done the T56 swap, what was the "bottom line" price for everything, including pedals, clutch, custom mounting, etc?

 

Can this come from INSIDE the transmission? I hear it oh-so-often on 2-3 upshifts.