2000 Mountaineer faint clunking

[monkeydude3]

Hello all~
Ok so my girlfriend's mom has a 2000 mercury mountaineer. It has the 5.0L v8, automatic, and all wheel drive. Just about every goodie on it as was possible.

All I've heard is what she told me, and she let me drive it once around a few blocks to hear it myself.

The problem at hand is when you hit the brakes with some decent pressure, not necessarily slam on them, a very faint clunk is heard. Not quite sure where it's coming from, sounds like the center/middle underneath. Not sure if it's a high speed or low speed thing, as it happens at both and is intermittent. It seems to increase in frequency depending on how rough I am on the brakes. I've read it could be any flew of mounts as well underneath, tranny mount, rear leaf spring mount...

I found a TSB on AllData regarding an internal transmission spring that's out of adjustment on the planetary gears that will cause a clunk from 2-1 downshift, but that's only when it's consistent.

Other than that (and needing new brake pads and rotors) it's doin fine. Any idears would be great.

Take care!

George

 

[monkeydude3]

I also did an experiment and let it coast to a stop to see if it clunked per that 2-1 downshift problem, and when it got down really slow, Blatantly in first gear, I heard no clunk to indicate the downshift. we're stumped.

 

[97BlackX5.0]

u joints are worn out in the driveshaft... my best guess... or youve got a balljoint clunking

 

[monkeydude3]

all right, thanks. Seems like she's got the same truck as you. It's so faint, and it only comes when you give the brakes some good pressure. It's really there when you wail on the brakes, but only at med speeds or higher. oh well
thanks

George

 

[97BlackX5.0]

if its a screeching sound it could mean the wear thingies on your brakes are telling you its time to change the pads... i'd do the pads and rotors and u joints and see if that takes care of it ..

 

[monkeydude3]

no screeching. Yes it does need new pads, and I'm betting she's letting them go beyond the point of no return in that they are going to start screwing the rotors up. It's such a weird clunking, could it be a mount of some sort somewhere? Thanks!!
George

IM me at monkeydude3 on AIM if you have it

 

[97BlackX5.0]

well a clunking when you change pressure on the accelerator pedal is usally slop in the driveline... mine clunks a little when i go from forward to reverse at slow speed and hit the gas a little... but i have never done my joints for the rear either... alot of people also have to grease the slip joint on the rear driveshaft.... id do the brakes pretty soon if you dont want to be replacing the rotors also... id do brakes then u joints... ujoints are pretty cheap... should be able to get a garage to do them if you dont feel comfortable doing them for under 150 bucks... even less if you buy the joints and take them in yourself... if you do buy them get the kind that have grease fittings on them so that you can grease them... that way they wont go bad for alot longer.

 

[monkeydude3]

I know exactly how to do U joints, I just need an impact wrench and that C clamp looking U joint press

George

 

[The"X"]

Don't forget to grease the slip yoke, they clunk sometimes when they're dry.