4.6 v8 explorer knocking noise when warm

[VictorClark94]

Hey guys this is my first post aside from posting an intro in the new members section. I got my 2002 explorer 2 months ago, it has 200,000 km on it and is in quite good shaoe for its age i would say. I bought it with a bad engine, sourced a known good used engine through the dealership i work at. The new engine has 116,000km on it. Before installing it, I replaced spark plugs, removed the front cover and valve covers to inspect the condition as im paranoid about used engines. All the timing hardware looked to be in great shape, there was zero sludge and varnish in the cylinder heads which was almost weird to me. I had all new timing stuff but it wasnt all oem ford so i just left it alone and replaced gaskets. Installed the new engine and used motorcraft 5w-20 and an fl-820 filter. Replaced the transmission fluid and filter, used mercon v of course. However after driving the vehicle and getting it up to operating temperature, when you put the transmission into drive, reverse, 3, 2 or 1 and the rpm drop down a bit you can hear what sounds like a rod knock. As soon as you put it in neutral or drive the sound goes away. Has anyone experienced this before, i have searched around and read about the torque converters being some what troublesome in these vehicles but i have not heard of many bottom end issues.
Any help/advice would be greatly appreciated. Thanks.

 

[SyberTiger]

Sounds like you are leaning toward a transmission related problem but did you rule out the harmonic balancer already?

 

[Hugh Janus]

Hey guys this is my first post aside from posting an intro in the new members section. I got my 2002 explorer 2 months ago, it has 200,000 km on it and is in quite good shaoe for its age i would say. I bought it with a bad engine, sourced a known good used engine through the dealership i work at. The new engine has 116,000km on it. Before installing it, I replaced spark plugs, removed the front cover and valve covers to inspect the condition as im paranoid about used engines. All the timing hardware looked to be in great shape, there was zero sludge and varnish in the cylinder heads which was almost weird to me. I had all new timing stuff but it wasnt all oem ford so i just left it alone and replaced gaskets. Installed the new engine and used motorcraft 5w-20 and an fl-820 filter. Replaced the transmission fluid and filter, used mercon v of course. However after driving the vehicle and getting it up to operating temperature, when you put the transmission into drive, reverse, 3, 2 or 1 and the rpm drop down a bit you can hear what sounds like a rod knock. As soon as you put it in neutral or drive the sound goes away. Has anyone experienced this before, i have searched around and read about the torque converters being some what troublesome in these vehicles but i have not heard of many bottom end issues.
Any help/advice would be greatly appreciated. Thanks.

The torque converter could be the source of the noise. You're gonna need to get a stethoscope to isolate further.
The 4.6L V8 does have issues with oil pump failure, you'll need to hook up an external gauge to see where it is at. When the bottom end goes, it usually spins a rod bearing. Isolating the noise with a stethoscope, and checking oil pressure are first steps - getting a second set of ears to listen can help too.

please update this thread as you go.

 

[VictorClark94]

Sounds like you are leaning toward a transmission related problem but did you rule out the harmonic balancer already?

Actually no I have not. Although I did keep the one off of my original engine so maybe after checking the oil pressure and poking around with a stethescope i will swap them out.

 

[VictorClark94]

The torque converter could be the source of the noise. You're gonna need to get a stethoscope to isolate further.
The 4.6L V8 does have issues with oil pump failure, you'll need to hook up an external gauge to see where it is at. When the bottom end goes, it usually spins a rod bearing. Isolating the noise with a stethoscope, and checking oil pressure are first steps - getting a second set of ears to listen can help too.

please update this thread as you go.

I will have time this weekend most likely to do an oil pressure test and check more thouroughly with a stethescope to pinpoint the noise. Hopefully whatever the source is can be relatively easily repaired. I would hate to have to pull the engine again ! And yes I will keep the post updated and ill try to take some pics and a video of said noise occuring.

 

[cougar190]

Something you might want to look at " 'ol school" . Check your torque converter to flex plate bolts/nuts. You say you replaced the engine. This is kind of rare but a possibility. ...cougar...