LuckyRabbit

Trade was made. Knock happens in WAVES. It’s not constant like a position slap. Truck seems great but they told me a little more info and a guy at O’Reillys has a theory after hearing it as well.

The truck was perfectly fine. The kid changed the oil, and added seafoam to the mix and the knock started. Not sure that seafoam had to do with this but it’s more info.

O’Reillys guy thinks it think the oil thinned out too much and not lubricating the everything correctly.

Another old mechanic I trust listened to it as it was doing the wave knocking. He said it sounds like the torque converter was loose and engine vibration was causing it to rattle. He said it’s a “thunk thunk not a tick tick”

Lenn

Something else to check just as cheap insurance but completely unrelated to your engine issue- check the area around and the cover for the fuse box under the dash adjacent to the drivers kick panel. Make sure there's no evidence of water staining. Plently of documented cases of windshields leaking from the top left corner and it's a direct shot down onto the GEM. This will cause tons of weird electrical issues. Best to handle that before it becomes a problem. An easy check is to see if the windshield is original, too.

marshallr

The 4.6 is one WEAK engine. My 2007 Tacoma is rated to tow MORE than my 2002 F150 with the 4.6. And my Ford had 3.73 gears. You better check the axle ratio and tow rating in it before buying. Some of them are only rated to tow around 2000-2500 lbs.

They are a pretty bullet proof engine but a poor choice for towing/hauling.

LuckyRabbit

Short video but here’s the sound. I’m going to out a couple YouTube videos up showing more of it but it’s just this.

LuckyRabbit

LuckyRabbit

Any help with this??

laterongc

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knock sounds bad. not saying i think it will definitely work, but based on the info you provided (seller oil info), seems like step one is changing oil and replacing with stock spec oil and quality filter. I'd do that before jumping up in viscosity. pretty hard to diag a serious noise like that from a vid clip, but i start with the easy things and rule out simple fixes before moving on.

LuckyRabbit

I’m going to the the gear oil and replacement oil first. And I have at least one O2 sensor out. Not sure that really can cause this issue but needs to be fixed anyway. I’ve heard the O2 sensor can actually be a bad EGR valve that actually can cause timing problems.

any ideas based on timing?

LuckyRabbit

I ran ATF for a bit to clean the old oil, replaced it with 10w30 and a new filter. It actually sounds “cleaner”. The top is definitely a “tick” now instead of a muffled “tuck”. Almost certain this is a dead lifter or still timing issue.

But the thing is.. the knock down low happens at start up bad, then below 700rpm. Any time the rpm drops, it knocks until it get back up to 700+

• park, tick only
• idle, tick only
• idle (with intermittent drops in rpm), tick and knock
• shifting into any gear, tick and knock
• turning the wheel all the way until it stops, PS noise but normal. But causes knock.

could this be a bad oil pump? Losing pressure? Gauges are fine. Or bad PS putting pressure on the belt?

JROC734

Sounds like a knock instead of a tick so I'm guessing rod knock. Maybe a spun rod bearing.?.? Just Coyote swap it.