[Tally TransAm]

we have a 03 GT automatic, approx 80k miles. the car has a metallic clunk/snap that is very evident when going from coast to drive at 40-60 mph. i know there is a tsb stating a tip in driveline clunk is normal but this is loud and very metallic

car has new (less that 3k miles) upper and lower control arms, freshly rebuilt trac loc, new ujoints. makes the noise with and without the quad shocks on, same with rear sway bar, and same with rear shocks. we have check control arm mounting locations, shock mounts, trans mount, ujoints, diff backlash, no play in axle bearings, etc

listening with a stethoscope, it is most evident on the diff cover both before and after the trac loc rebuild. but im having a hell of a time pin pointing it and fixing it

any suggestions?

thanks

 

[onehotpinto]

sounds like a bad u-joint

 

[LX546]

Sound like you may have a broken weld on one of you axle tube. I had the same sound in my 95 GT for months and I didn't find it until I launched it at the track and finished it off. I ended up spinning the axle tube taking out the drive shaft, brake lines, both shocks, and a brand new set of M/T Drag Radials. I recommend draining the fluid and weld up both tubes. It is cheap insurance.

 

[302man]

Sound like you may have a broken weld on one of you axle tube. I had the same sound in my 95 GT for months and I didn't find it until I launched it at the track and finished it off. I ended up spinning the axle tube taking out the drive shaft, brake lines, both shocks, and a brand new set of M/T Drag Radials. I recommend draining the fluid and weld up both tubes. It is cheap insurance.

WOW....thats rough. Glad you didnt destroy your car in the process !

 

[LX546]

WOW....thats rough. Glad you didnt destroy your car in the process !

Yeah it sucked. The worst was I drove it to the track and had to have it towed home.

 

[CobraChris]

I know you stated it sounded as though it was coming from the dif, but I would almost bet it's coming from the trans. There is a small spring in there that sits on imagination, that's called the anti clunk, or sun gear support spring. It comes out easily, and makes exactly the sound you describe. It literally just wedges between the case and sun gear.

Just a thought.

 

[302man]

Have to love the cheap fix !

 

[notch 501]

what ever it is fix it, friday broke a diff car went sideways kept it off the wall

 

[Tally TransAm]

sounds like a bad u-joint

they are brand new. same noise before and after

Sound like you may have a broken weld on one of you axle tube. I had the same sound in my 95 GT for months and I didn't find it until I launched it at the track and finished it off. I ended up spinning the axle tube taking out the drive shaft, brake lines, both shocks, and a brand new set of M/T Drag Radials. I recommend draining the fluid and weld up both tubes. It is cheap insurance.

Ill double check that. I looked up with the car in the air and didnt see evidence of it. ill check on under load as well

I know you stated it sounded as though it was coming from the dif, but I would almost bet it's coming from the trans. There is a small spring in there that sits on imagination, that's called the anti clunk, or sun gear support spring. It comes out easily, and makes exactly the sound you describe. It literally just wedges between the case and sun gear.

Just a thought.

i was originally thinking trans as well. the only thing that brought me back to the diff was not hearing it at all in the trans case with a stethoscope. but its loud as hell on the diff cover, unless the unicorn is making the noise just travel down the driveshaft

 

[Mach1 Motorsports]

If it was trans you would hear it on the case.

Just because the u-joints are new it does not mean they are good.

 

[CobraChris]

i was originally thinking trans as well. the only thing that brought me back to the diff was not hearing it at all in the trans case with a stethoscope. but its loud as hell on the diff cover, unless the unicorn is making the noise just travel down the driveshaft

Ahh cool. So you actualy got under the thing and were listening. Yea, that kind of rules it out.

 

[GT 350]

you install the track lock kit right ... if you dont stack the plates and clutch right it will pop and make noise ive seen many done wrong... even from the factory

 

[rdub79]

Not enough carrier bearing preload will also cause this, allowing the ring gear and trac-loc to spin too freely and when going from coasting to accelerating, the gears teeth abruptly engage and make a clunking sound.

The first rearend I setup did this ..

It should be tight enough that you should have to tap the shims in with a dead-blow hammer when installing it, and you should have to use a pry bar to get the carrier (trac-loc) out when removing it.

 

[REDN2OHATCH]

Try some friction modifier..clutches may be stickin..worth the few bux to try

 

[Randy Stinchcomb]

also check the rear, lower control arm bolts. they are common for breaking, esp the front left rear lower mounting location. FoMoCo changed the bolts size from 12mm to 14mm in 1999(?) and if you get aftermarket control arms, they could have come wth the smaller size 12mm bolts.

 

[GT 350]

I would like to know how it was stacked ...clucth, steel .. or steel clucth

 

[Tally TransAm]

I would like to know how it was stacked ...clucth, steel .. or steel clucth

small update. pulled the clutch packs out again. the first time we put them together we put them in the same way they came out. which i believe was not correct

this time we put them in according to this

noise is still there. noticeable clunk from the rear anytime you go from coast to throttle

damnit

 

[GT 350]

small update. pulled the clutch packs out again. the first time we put them together we put them in the same way they came out. which i believe was not correct

this time we put them in according to this

noise is still there. noticeable clunk from the rear anytime you go from coast to throttle

damnit

is it auto or stick car nevr mind i see auto

 

[GT 350]

How much play do you have on pinion moving back and forth

 

[Tally TransAm]

pinion is tight, no movement