I have a 98 F-250 LD truck with 5.4 about 175000 miles. Runs great, drives great, but is begining to have a rattle while it is idoling in park and drive. Sounds like it comes from the gut of engine or the transmission, but transmission seems to be fine and I have never had a problem with the truck at all. Engine does not have a knock so it is not that. Please help if you can so I can fix it ASAP.
Thanx,
Fordman98

heat shields on the exhaust maybe?

You sure Ryan isn't any where near your engine?

Fordman98 said:

I have a 98 F-250 LD truck with 5.4 about 175000 miles. Runs great, drives great, but is begining to have a rattle while it is idoling in park and drive. Sounds like it comes from the gut of engine or the transmission, but transmission seems to be fine and I have never had a problem with the truck at all. Engine does not have a knock so it is not that. Please help if you can so I can fix it ASAP.
Thanx,
Fordman98

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Check the torque converter bolts.

It is a short bed. Last year I had a vacum leak and that made the rpm's idol at about 2500. Put it in gear and then it would idol about 1000. It started the rattle soon after that.Just wondered if that hurt it any. Thanx,Fordman98

Fordman98 said:

It is a short bed. Last year I had a vacum leak and that made the rpm's idol at about 2500. Put it in gear and then it would idol about 1000. It started the rattle soon after that.Just wondered if that hurt it any. Thanx,Fordman98

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Buy an inexpensive mechanic's stethesope and start checking the various parts of the engine near where you think the sound is coming from. If the sound is loudest in the oil pan you have problems coming. My '98 expy had a rattle that I traced to the rear of the oil pan. I dropped the pan and found the bearings spun on the last rod journal. They were real bad but made very little noise, like a slightly loose rocker arm. Drive it gentle until it has to be replaced or trade it and then the dealer can worry about it.