Mysterious drivetrain clicking sound

[badmotorfinger1]

Hello all,
I have a 2007 Mountaineer AWD 4.6L V8 with 47,600 miles.

Within the last week, it's developed a strange clicking sound similar to the baseball card in the bicycle spokes. The clicking sound seems to be coming from the firewall area on the driver's side.

The clicking is variable with engine RPM and only when accelerating. It gets louder going uphills vs. flat roads indicating an engine load variable. With the tranny in park and the engine revved up, there is no noise. However, with the tranny in drive or reverse and with the brake engaged (vehicle not moving) and the engine revved up, I can hear the click. I would assume this test eliminates an axle, U joint, or transfer case issue.

I suspect the transmission based on the symptoms and tests I've conducted, have checked the fluid level and it appears to be fine, but I'm really stumped. Anyone experienced this before or have any ideas?

Thanks in advance.

 

[kam327]

Based on your test with the brake engaged, it could very well be the torque converter since the tranny itself and the drivetrain behind it wouldn't be rotating.

My torque converter just went bad at 57,000 miles. Hoping it get fixed today.

 

[badmotorfinger1]

Thanks for the response. Ironically, that's what I've been thinking about this morning. I've never had a TC fail on me before so I'm not sure of the symptoms.

 

[kam327]

Me either. My symptoms are a slight bump in RPM every 1.5-2 seconds while cruising down a flat road at around 35-45 mph. Also, on a couple of occaisions I heard a strange noise while accelerating when it shifted into maybe 4th or 5th, almost like going over a rumble strip on the side of the road.

 

[Kevin-Truro,NS]

Exhaust manifold leak, maybe? If a small enough leak, it would only be heard under load...

 

[badmotorfinger1]

My tranny shifts very smooth, no lurching, slipping, hesitation or jerking.

When I get home from work this evening, I'll have a friend sit behind the wheel, hold the brake, and rev up the engine while in drive while I try and isolate the exact area the clicking is coming from.

I'm keeping my fingers crossed that it isn't a bottom end issue and the crank isn't moving fore and aft under load.

 

[ford_67]

Strange clicking sound

My 97 AWD started a clicking noise about a year after I bought it in 2003. I have tried to figure it out but to no avail. I started having the notorious TC shudder about a year and a half ago. I do not drive it that much because I have a company truck. At any rate I am replacing the transmission now. I will let you know if the noise goes away. That will give you more to go on. I know this is not an answer to your problem exactly but it may lead you to it and it is also good to know you are not the only one. I will keep you posted. Hope this helps.

 

[zukman]

your left front hub is toast

 

[ford_67]

Clicking noise

On my 97 I have replaced both front hubs and the noise is still there. I also checked front axles and front drive shaft.

 

[kam327]

your left front hub is toast

That doesn't gel with the OP's statement: "with the tranny in drive or reverse and with the brake engaged (vehicle not moving) and the engine revved up, I can hear the click"

 

[badmotorfinger1]

I'm glad to report the mystery is solved! With the Merc up on ramps, parking brake set, and wheels blocked, I had my neighbor rev up the engine with it in drive while I put a stethoscope on the tranny and bottom end of the engine. No click coming from there. Huge relief.

Traced the clicking to the drivers side cylinder head at the #7 piston. After a few more experiments, I found I could make the click start and stop by slightly rotating the coil pack. The coil pack and spark plug checked out ok, so I just cleaned everything up and reassembled. Clicking is gone. I even went so far as to try and make another cylinder click, but couldn't duplicate the noise. No indications that the click was due to a misfire and I'm puzzled as to why the click happened only when it did, but I'll contemplate that later.

Thanks for everyone's suggestions.

 

[WaltZ]

I love these forums

Every time something goes wrong, it's already happened to someone else.

The clicking sound [sounds like a rock stuck in a tire] has been going on for a week right after I got new tires and alignment. I also live on a gravel road. I checked the tires, but no rock stuck. Its sounds like its coming from the passenger side in the center area. Only happens on acceleration and gets quicker as speed increases up to about 50 mph, then seems to goes away.

A month ago, I had a blinking CEL and it ran really rough. I limped into Midas. They diagnosed a possible bad plug and/or coil [all plugs replaced less than 30k miles ago]. They cleaned up some coils and its been running fine up to now. I can't believe my $22 plugs could have gone bad that fast.