Can't drive! Loud rattling noise from front end

[Tekime]

Hi all, I could really use a bit of help.

My 2000 Explorer V8 Eddie Bauer just started making a horrible rattling noise from the front left area of the engine. I searched around and fear this might be the transfer case, and I could use any advice at this point.

I bought this truck ~6 months ago from a local dealer and it has been great so far - strong through all gears and I put about 12k on it so far (about 125k on the engine now). Last month I damaged the left front tire and went to have it replaced (after driving on it for a few weeks with an unnoticed ribbon worn off the inside edge). I was told that running the wrong size tires can cause wear that may damage the transfer case. They also discovered that the front left tire was the only *correct* size for the truck - the rest were just one size larger. So I put four new tires on it of the correct size a few weeks ago and put ~500 miles on it since.

The noise just started - I thought I heard something a few days ago but only briefly. On my way home it started in very badly and did not stop. It's a very loud metal clanking/rattling noise. The noise seems to follow RPM not wheel rotation. When revving it starts clanking/rattling louder. When I speed up a bit and then let off the gas it clanks even more loudly and the frequency slows down. I can almost get it to stop by revving the engine just slightly while rolling. It's quiet while idling at a stop.

I don't know a heck of a lot about this vehicle, or AWD in general, but it almost seems like there is still power from the other 3 wheels, but whatever is supposed to be driving the front left isn't syncing up or is slipping.

Very appreciative of any advice you folks might have!

Thanks,
Gabe

 

[gavin]

couple questions for ya, and a couple things to try.

#1 - what sizes were the tires originally on the vehicle? do you remember?
#2 - you replaced ALL tires with a SET of NEW tires, correct?
#3 - Do you also feel a harshness/vibration with the noise?
#4 - where do you live? or, more importantly, what is the weather like? if weather permits, remove front driveshaft (temporarily), and drive a couple miles to see if noise persists.

It really does sound to me like the cv-joint on your front driveshaft (the "joint" at the transfer case) is toast, and your front driveshaft will need replaced. By removing the shaft temporarily, will help diagnose this issue.

 

[Tekime]

Thanks for the reply. I would pretty happy if it were the CV joint (at least compared to needing a new transfer case).

#1 - what sizes were the tires originally on the vehicle? do you remember?

255/70/R16 on left front and 265/70/R16 on the other three IIRC.

#2 - you replaced ALL tires with a SET of NEW tires, correct?

Correct. All four with a brand new set. I thought they were putting 255/70/R16 on since that is what the door marker says, but I just checked and they are all 265/70/R16. Definitely all new and all the same size now.

#3 - Do you also feel a harshness/vibration with the noise?

No major vibration that I recall - but then again I crept the last 1/2 mile home when the noise started.

#4 - where do you live? or, more importantly, what is the weather like? if weather permits, remove front driveshaft (temporarily), and drive a couple miles to see if noise persists.

Unfortunately I live in Maine. About 12F out and snow on the ground.

It really does sound to me like the cv-joint on your front driveshaft (the "joint" at the transfer case) is toast, and your front driveshaft will need replaced. By removing the shaft temporarily, will help diagnose this issue.

Do you think there could be any physical sign of wear or breakage to look for without removing the driveshaft?

Thanks again for your help.

 

[gavin]

atleast not a huge difference in size on the tires... but of course still not good.

you could inspect the rubber boot and see if there are any rips or tears. Although when my first shaft's cv died, there were no physical signs.

and I'm trying to remember if I ever felt any vibes... I'm thinking that I didn't for a little while, just the clunking noises.

chock the tires and pop the truck into neutral; try to feel for any play in the shaft at the cv, up/down, side/side, and rotational. It should be really solid (there will be a little rotational play due to the t-case, though, which is normal)

 

[Equnoxe]

stick your head underneath your drivers ride while the noise is there if you can. i had the same noise (sept i have V6SOHC) and it was the left CAT. always rattles when it is cold or between 2700 and 3000 rpm..... need to replace mine. may not be your problem but that's what mine was! super embarrassing loud rattling/crackling noise?