SOHC new noise at cold start!

[2000XLT4X4]

Hello All!
New here, but have visited and searched in the past for answers. Great site!
Anyway, I own a 2000 Explorer, SOHC. Live in the Chicago area. Haven't really used the four wheel drive much. This past week we had a pretty decent snowfall. I used the four wheel in high for the drive home from work, no issues. Now I don't think having used the four wheel has anything to do with the problem I now have, but thought I'd mention it.
Since that snow day, temps have been in the single digits up to maybe 25 degrees. When I start the truck cold, I hear(and feel under the floorboard) a nasty thumping/thudding sound coming from under the truck, but it starts right up and the sound instantly goes away (maybe three or four thumps while cranking). I can drive the truck home and not hear anything unusual. If I immediately shut off the engine and restart it, I do hear the sound again. But, if the truck is warmed up, and it's shut off, then restarted, no noise.
I'm about to make an appointment at my local Ford dealer and have it checked out. This truck has been reliable for the most part during it's 6 years and 80,000 miles. It did have the camshaft chain tensioner replaced at 18,000 under warranty/service recall.
Anyone have any experience with this problem? Thanks. I'll check back later to see what you say. I'm working graveyard shift right now and am about to hit the hay.

 

[slpdave]

I had a simular problem with a Camaro years ago, it was caused by a broken tranny mount. The difference is that mine did it whenever I hit the gas hard.

Don't know if the 4X4 tranny could be giving any problems or not.

 

[2000XLT4X4]

Thanks for the reply, Dave.
You might be onto something there with the trans mount. I did notice a bit of vibration, although slight, when I backed out of the parking space at work. No vibration when I drove off.
But then, I don't know why it wouldn't make the same noise when warmed up?

Any other ideas what it might be?
Thanks,
Bill

 

[2000XLT4X4]

OK,
When I got home, I shut off the engine, took a look under the truck. There was a considerable amount of ice frozen on each side of the truck on the a-arms(?), where they attach to the frame on either side of the engine. I kicked it off. Then tonight when I left for work, I expected to hear the same noise I had been hearing........started the truck, NO NOISE!
We'll see when I leave work this morning if it comes back. I have no idea what the ice may have impacted, but then maybe it melted enough after starting to quiet it, then refroze to cause the interference again?
I'll repost again and let you guys know the status. If it was just the ice.....I'll have to react like Homer Simpson and say........"DUH!"

 

[slpdave]

I hope it is the ice causing your problem, I live in east Tennessee where we had our first cold night (for us it was cold but it was 23 degrees) of the year. I believe it is probably the coldest it's been since last christmas. Temps in the day are 40+ so ice is absolutely not a problem here most years.

 

[2000XLT4X4]

Looks like the ice was the problem. Wish I could have actually seen the problem at hand while someone else was cranking the engine. Anyway, thanks for the replies. Keep warm, winter is here. Not necessarily a bad thing, as I enjoy ice fishing.
Bill