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Rarely the motor mounts with these vehicles, should be ruled out regardless. The heat shields are more common..particularly the smaller (but much more restrictive) upstream shields.
The spot welds give way at the corners one at a time. If it's just one weld, it might take some pressure to silence it. More than one weld on the same side and you should notice a change in pitch /vibration immediately.
EDIT: Could also be the brick or honey comb. They can crack and make a vibration noise. In the past, a friend with Grand Marque had one of his replaced because that. That one was noisy at a certain speed.
Spot welds on what? The heat shields? I will look at those next, as well as seeing if maybe a rock got jammed in somewhere. This will probably take me until next weekend, unfortunately.
Here's what my crossover pipe hanger looks like. Same sandwich plate. View is from PS, trans crossmember to the right in the pic.
Put it on stands today to inspect. The heat shields seem sound. touching them makes no change. The vibration is felt clearly in the engine/transmission and exhaust, and there was nothing I could reach that changed the vibration.
In the way it had nothing to do with noise.... if you did so while it was running. You did mention you could hear it at idle. Mean, noise probably has no relation to the power plant/transmission if it didn't so much as change....even a little.
EDIT: Hadn't seen your most recent post above yet CO before typing this one.
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Thought I lost the desk top this morning. Hard a strange power outage before I woke up. First unusual thing noticed, -only a few of clocks without battery backup were blinking while others were fine. Computer was off, LCD's were on but sleeping, surge protector was in the green as well...which is normal. However the desktop wouldn't fire back up.
So, switched the main shut in back of DT on and off, then attempted to fire it up normally again through the switch in the front..nothing. Scoped everything out again under the desk with a flashlight (DT has a transparent case) didn't notice anything unusual. Great! Decided to pull the plug on the power strip, give it a little wait then reconnect it. Everything connected to the strip fired back up fine automatically as usual, and now the DT starts again. That shouldn't of worked.
Never the less, glad it did
Must of had a brown out vs a black I expect.
EDIT #2: Somethings going on. The neighbor next to me down the road is on generator and the neighbor way behind me is on generator. Power company has 3 trucks on the side of the road now. I have power, generator never fired, power failed here for second at some point, came right back. Strange though for out in the stix, when the power fails around here ,we all go out..always . Not this time, and it's not my fault either lol.
Here's what my crossover pipe hanger looks like. Same sandwich plate. View is from PS, trans crossmember to the right in the pic.
Put it on stands today to inspect. The heat shields seem sound. touching them makes no change. The vibration is felt clearly in the engine/transmission and exhaust, and there was nothing I could reach that changed the vibration.
Never seen that before..yea that's totally different. Can't see it all, see enough though....much different vs 97/98. Curious which year that changed. Looked again , -Man, that set up looks heavy duty....much better then what they have on the earlier models.
I guess I should start my posts differently...for example, - The 97/98 cat heat shields are spot welded at all four corners on the upstream converters...more less tacked. Those commonly and eventually let go with time.
In the way it had nothing to do with noise.... if you did so while it was running. You did mention you could hear it at idle. Mean, noise probably has no relation to the power plant/transmission if it didn't so much as change....even a little.
Got it. So it does impact the vibration, in that it will only do it at idle in R or a Fwd gear - not while unloaded. Could be due to the load or the idle speed, not sure. The engine hardly moves, though, when changing gears, which would seem to rule out motor mounts.
Never seen that before..yea that's totally different. Can't see it all, see enough though....much different vs 97/98. Curious which year that changed. Looked again , -Man, that set up looks heavy duty....much better then what they have on the earlier models.
I did completely remove it and visually inspected the isolator, which is a hollow square of a soft material. It looked to be in good shape - no cracks, even thickness on all four sides. The trans side of the mount is basically a piece of square stock that goes inside the rubber square.
So do you think I have one of those phantom bad motor mounts (when they pass every test you can think of but they are still shot, somehow), or something wrong with engine internals, or maybe something with the torque converter, or maybe something with the exhaust other than this one hanger (maybe the connectors at the manifold)? I guess it could also be idle speed, but it seems there's nothing that can be done about that (idles around 550-575 in gear, which I believe is actually correct).
Last edited by COStruck; Jun 25, 2023 at 04:55 PM.
If the visual inspection past on the motor mounts as well (no cracks or pieces moving). I would think they're fine. I've seen people change the motor mounts in the past on these trucks in the past...the old ended up being fine. They were questioning the movement. All said and done, didn't make a difference with the new ones..
Yea , that Y support is definitely beefy, they even incorporated heavy gauge square stock lol. The 98 is just a 1/8" plate that lays flat on top of the trans mount with sort of finger piece. Two pieces of rod stock connect to the finger (about the size of a muffler clamp rods) The rods slip into a bushing above that. 1"x2"x1/2"...tiny bushing. That bushing doesn't last and the plates break...actually crack from the finger across the top of the mount.
Perfect warm idle in park is 725 rpms. Fords tolerance is 700-750 rpms but they are usually right around 725, very close to it and steady where ever they are. In drive at a stop they are a little lower. I can't recall that number exactly, I want to say 600. You might be right on that..didn't think they dropped that low. Don't think I've ever looked lol.
Wouldn't worry about anything internal...nothing comes to mind.
Perhaps you have something wedged in your ear tunnel ? Or is that too outside the box ?
Last edited by Jbrew; Jun 25, 2023 at 07:00 PM.
Reason: Final thought
If the visual inspection past on the motor mounts as well (no cracks or pieces moving). I would think they're fine. I've seen people change the motor mounts in the past on these trucks in the past...the old ended up being fine. They were questioning the movement. All said and done, didn't make a difference with the new ones..
That is my worry. It's an awful lot of effort for a wing and a prayer.
Perfect warm idle in park is 725 rpms. Fords tolerance is 700-750 rpms but they are usually right around 725, very close to it and steady where ever they are. In drive at a stop they are a little lower. I can't recall that number exactly, I want to say 600. You might be right on that..didn't think they dropped that low. Don't think I've ever looked lol.
It's something like that in P, but it doesn't vibrate at that RPM.
Perhaps you have something wedged in your ear tunnel ? Or is that too outside the box ?
Haha, could be. Probably not though, because my wife and my one buddy also feel it. It's more felt than heard. We all feel it in the steering wheel, the pedals, and the door panel.
On another note, now my parking brake isn't holding. Which way do the star wheels go to tighten it up again?
