Hi everyone, I have a head scratcher, here.

Basics-
2000 E350, 5.4L
237K miles, 4sp OD
towing 5X8 trailer (yes, we're a band)

On this last trip I noticed when pulling a grade and the transmission downshifts to 3rd gear, after a couple of seconds you can hear a tapping sound coming from up front. Just as soon as the tranny upshifts back to overdrive the tapping stops. Immediately.

I got to a parking lot, put the van in park and revved it to about the same amount, or as close as I could remember (stripped down van, no tach). The noise never appeared. So it seems the problem occurs only when under a load.

I also noticed that locking OD out and getting the van up to about 65mph on level ground will make the noise happen, so it's not just a "pulling a grade" thing. It seems that the noise is when the engine is revving that hard.

In all other ways, the van seems fine. No Service Engine light, runs normally, same fuel economy, engine purrs (new plugs about 10K ago) Same level of performance as always.

Any ideas out there? My brother in law is up on this stuff, he's stumped, but mentioned perhaps torque converter (I've done fluid changes at specified intervals) or perhaps motor mount. The noise sounds pretty far up front, so I'm stumped. I can't find anything wrong.

The only thing done recently is the last oil change was from using Valvoline Extended Life (high mileage) oil to Castrol regular oil. 5W30, changes every 5K miles. Almost all highway miles.

Any suggestions or input appreciated.

Ben

 

Hi Ben!

Could you have an exhaust leak from one of your manifolds? These engines like to shear off manifold studs and leak after a few years, and that could cause some noise. If not that it could be something going bad in the transmission, as the one constant seems to be when it drops to third gear.

If you're in a band you must have some recording equipment. How about a video for us to hear what you are?

 

Hey Tom, that is a very good idea, and I've already fixed that problem. When the head bolt sheared, it gave a quick exhaust leak sound right at startup, and then while coasting downhill it would made a funny sort of tap/suck sound. It wasn't until I was changing the oil one day that I noticed the carbon leaking between the head and the manifold and saw the snapped off head bolt.

As for this problem, I meant to mention that the tapping noise seems independent of engine rpm- that is, the tapping seems to be the same speed when it occurs.

What does a bad motor mount sound like? If it was a tranny thing I think it would change with speed, but I might be wrong about that. As I said, I am open to ideas.

As for the band- Yes, I have a recording studio here in Nashville, the band is my wife's- Missy Raines and The New Hip. Here are some links to explore, enjoy!

Missy Raines
www.facebook.com/missyrainesandthenewhip
www.twitter.com/thenewhip
Missy Raines - YouTube

Ben

 

to check your engine mounts, open the hood, start the engine, and have someone watch the engine while you hold the brakes firmly with your left foot, then shift into drive and rev the engine a bit, then shift to reverse and rev it a bit. the engine will move a little on good mounts, or a lot on bad mounts. most people who haven't seen this test will respond with "holy crap, it moves?!" so don't let it scare you, it'll move a little, but shouldn't be more than an inch or so.

 

A bad motor mount will cause clunking because the rubber collapses which permits metal-on-metal contact. But it wouldn't be a constant clunking noise, but rather a clunk as you roll on the pedal and maybe a clunk as you roll off. A constant clunking under steady acceleration shouldn't be caused by that unless your engine is running badly.

Let us know what you find!


Wow, thanks for the links!

 

This is not a clunking noise, so that's ruled out. Dang, it looks like it's off to the mechanic.

Thanks for the help, if there are any other ideas, pass them along. Since it's an engine thing (I think) I may repost in another forum.

Have a good one!

Ben

 

Hey, just wanted to let you all know I figured it out, then got some help from my mechanic.

Noise started happening louder and more regularly. Me and mechanic went for a test drive, he did everything he could to make sure we didn't have a detonation situation, or some sort of valve train issue. both of those cleared themselves in the test drive.

I had started figuring out it was probably the belt tensioner. With some more work, the mechanic thought it was too, so he pulled it out.

Funny thing was, the pulley bearing wasn't that bad, but the pivot kept binding. Mechanic said he thought under hard acceleration it would start hammering.

Anyway, it's all good here now, just wanted to drop a line and say thanks. I lurk on this forum a lot, always appreciate the conversation

Ben

2000 E350 15 pass
5.4L Triton

 

Great news for the relatively easy and cheap (??) repair---considering what it could have been!

Thanks for updating us too----could prove helpful down the road to someone else with the same situation.