Knocking noise from the bottom of engine

1999 FORD RANGER
300,000 MILES • 4 CYL • 2WD • AUTOMATIC
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CARGUY513
  • MEMBER
  • 2 POSTS
So there is a loud knocking noise seemingly coming from bottom of motor (I think) but it doesn't start knocking until it gets warmed up and then it seems like if I go faster it gets faster but of I stop it still knocks but if I put it in neutral it will stop and become silent but as soon as I put it in drive then it starts knocking again. The truck listed above has 350,000 miles, but had a motor put in so not sure exactly how many on the new engine (used engine). thanks for any help fellas or lady's.
Nov 13, 2020 at 10:29 AM
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ASEMASTER6371
  • CERTIFIED EXPERT
  • 52,796 POSTS
Good afternoon,

You could have an internal issue with the motor. I would start by checking the actual oil pressure to be sure there is sufficient pressure to the bearings.

https://www.2carpros.com/articles/engine-noises

Low pressure could cause this.

https://www.2carpros.com/articles/high-or-low-engine-oil-pressure

The other possibility is a cracked flywheel. It would only make a knocking noise under load which would be when it is in gear.

The transmission needs to be removed to gain access to the flywheel.

I attached a YouTube video for you of the removal.

https://www.youtube.com/watch?v=AyG4xmSWylE

https://www.2carpros.com/articles/transmission-replacement-removal-manual

Roy

Removal
1. Remove the transmission/transaxle.
2. Remove the clutch, if equipped.


imageOpen In New TabZoom/Print


3. Remove the flywheel or flexplate.
- Remove the bolts.
- Remove the flywheel or flex plate.


Installation

NOTE: Engine balancing is not required. Balance weights should not be installed on new flywheel.

NOTE: Special bolts are used for installation. Do not use standard bolts.

1. Inspect pilot bearing (manual transmission only). Install a new one as necessary.
2. Install engine rear plate, if removed.
3. Install the flywheel or flexplate and flywheel reinforcing plate on the crankshaft.


imageOpen In New TabZoom/Print


4. Tighten the bolts in a criss-cross pattern.
5. Install the clutch, if equipped.
6. Install the transmission/transaxle.
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Nov 13, 2020 at 11:22 AM