[prima_materia]

So not too long ago I switched out the transmission pan/gasket/etc with a new ZF trans pan kit, along with new T40 torx bolts, and 6L of new ZF fluid. The car has drove, shifted, etc great, no funny business.

Fast forward to today, I went to start the car, let it warm up briefly [1 minute], backed the car out've the garage, put in park, then this metal, fairly fast & consistent clanking noise that seems to be coming from right under the drivers side right where the front driveshaft/u joint mates up/connects with the transfer case.

Now, on to some specifics that I 'think' I overlooked and screwed up on: when I had the car up in the air and noticed where the fill bolt was [blocked by the front driveshaft], I ended up having to unbolt the 4 bolts that hold the driveshaft/u joint to the transfer case, filled with fluid, started it for a few minutes, ran through the gears, lowered, repeated the filling procedure twice more until the trans took nearly all 6L of ZF fluid.

Upon reading the bentley manual it mentions that the 4 bolts are to be replaced [ZNS bolts], though I read on 1ddicts that techs have reused those bolts? Also, I tightened the bolts to spec per the bentley manual [15 ft/lbs +addit 45 deg.], though the bentley manual ALSO states that you're supposed to mark the orientation of how the u joint/driveshaft mates up to the transfer case...which I didnt do.. I'm not sure what this rattle could be, aside from the few things I just mentioned. I'm going to get the car up on jacks today, as I won't have lift access til tomorrow :/

Is anybody able to help me out with this, it'd be greatly appreciated. Did I f$#* something up? I really feel like a tard for not being more thorough, meh, I digress.

PS: Weird thing is that after driving the car for 15+ minutes, then coming back and parking it - the sound is completely gone. I can get a video if need be.

Appreciate it..

[bahn]

Is the sound present while stationary? If so then you can rule out the drive shaft. Can you get a video? A lot of the time on a cold start you'll hear the HPFP tick loudly. It should go away above 1200 rpm though.

[prima_materia]

Originally Posted by bahn

Is the sound present while stationary? If so then you can rule out the drive shaft. Can you get a video? A lot of the time on a cold start you'll hear the HPFP tick loudly. It should go away above 1200 rpm though.

Yup, I'll go outside and get a video right now, will have to post it on my youtube channel then upload the link here, gimme a bit. Will post back here within the hour. Thanks for the response, appreciate ya.

Yeah, I stuck my head under the drivers side front door right near where the u-joint connects right up to the transfer case and it's coming from that general direction, though im about to get it on jacks, start it up and I'll grab a video.

[prima_materia]

Here's a video of it. Sorry for the poor quality video.

[prima_materia]

Just did a small test:

Car in park - noise

Car put in reverse but foot on brake/still stationary - noise

Foot off brake & let roll in reverse - noise stops

Foot back on brake while still in reverse - noise

Shift into D, S, or M mode and light-med acceleration - noise stops

Not sure what to make of this.

About to jack it up here shortly; and i'll make a better video with an LED light.

[bahn]

Originally Posted by prima_materia

Here's a video of it. Sorry for the poor quality video.

Sounds like a heat shield rattling imo.

[prima_materia]

Here's another one, but better lighting. Towards the end of the video the noise ends up going away..

[prima_materia]

Originally Posted by bahn

Sounds like a heat shield rattling imo.

That's odd, but it wouldn't surprise me. I'll hunt around for the noise, I'll check the small heatshield on the passenger side that i had to unbolt [3 bolts] to access a few of the T40 torx screws on the trans pan. Weird though because I tightened that down really snug..

[prima_materia]

Well, after scopin things out, looks like these were the culprit,

thaaaank god

Two separate exhaust brackets/hangers, which all were 'tight', though they weren't 'real tight', had to muscle it a bit, nothing crazy but they definitely could've been tighter.

Funny though, after lookin over the u-joint and driveshaft and thinking it was that I had moved over to the passenger side, flipped the car on, got underneath, got close to the hangers. I could touch them with my fingers and feel the vibration ..so then I grabbed them firmly and the noise immediately stopped lol. Did this several times, and it was obvious.

**Top pic is torx on exhaust bracket.
**Bottom pic is the other two torx bolts

w00t!

[prima_materia]

Well, spoke too soon. Started up the car this morning to head to work and the sound resurfaced. Good times let me tell you lol [49deg outside].

So drove to work and the car ran good, pulled into work and went to the passenger side of the car and put my head underneath by the exhaust; I think it's coming from either the heat shield possibly or one of those exhaust hangers. Funny thing is that in the two pics above - the first picture of the exhaust bracket with the single torx - I touched it while the car was rattling this morning and it somewhat stopped, but not fully.

I don't understand because I ''re-tightened'' the bolts in those pics that I posted above - yesterday, and it stopped upon startup and was fine up until now lol

Also, this noise 'seems' to go away after 20-30 minutes of driving and once the car heats up.

Will try to get it on my buds lift today after work for an hour so I can check things out.