After 275,000 miles of amazingly reliable and hard working service, I'm afraid that my '92 F350 7.3 is giving me some serious "rebuild me now, or I'll grenade" signals. A couple days ago, I pulled into the driveway after a 4.5 hour drive and heard what I guess is best described as a low, whaump, whaump, whirring coming from the back of the driver's side of the engine. It doesn't sound good. At first, I thought it may be an exhaust leak, but then, as I stuck my head under the fender, then under the truck, it seems to have a rotational sound. Sounds like a worn out bearing, but it's not "knocking", it just sounds like some serious friction. I checked the oil, and it was about a quart and a half low, which isn't that unusual, as I had been on the road all weekend, and it often uses (both burns and leaks) about that much. I added oil, and it quieted down a little. So, if anyone has any ideas on what I can check, I'd love to hear it. At this point, I'm going to assume the worst and start planning to rebuild her. Does anyone here have a good recommendation for a source on rebuild kits? I see several online, but I want to be sure that I end up with a good one. Good price helps also. I also will need to finally purchase a real service manual. What is the best one? Factory? Sources? I done all my work on this truck so far without a manual, which has been ok, but I'll definitely need it for a rebuild.
Thanks for any help.

Nathan

 

Woofing sound out the exhaust can be caused by a bad valve,might be worth looking into it.

 

Is a compression test the best bet to determine if a valve is bad without pulling the head?

Thanks.

 

Yes a comp test may show which cyl to look at,or you can pull the valve cover and look at the valves for any physical probs(worn or damaged rocker arms).Also try wiggling the valves sideways for play,this can show worn guides.

 

Thanks pnose, I appreciate the suggestions.

The good news is that I have found the problem. When I fired it back up to nurse it into the closest local shop with a comp tester (mine is at home, I'm still out on the road), the noise was about the same, still hard to tell what I was hearing. Then, as I pulled into the market to grab a soda on my way to the shop, I rolled down the window and realized that the noise was MUCH louder. I thought that I had done it now, it was about to grenade. Then, as I throttled back on into the parking spot, the noise almost stopped entirely. I skipped the soda and just nursed it down the 1/4 mile to the shop. As I pulled in, the local wrench could hear me coming from a ways away and was standing there smiling and shaking his head. I shut it off and he walked up and said, "sounds like your torque converter bolts are hitting the inspection cover". We crawled under, removed the cover and found that the nuts holding the flex plate onto the TC were a little loose. We tightened them, and the noise stopped. I had the trans replaced with a rebuilt, "updated" E4OD about a year ago (23,000 miles). Evidently, the jackass that installed it reused the original nuts, and managed to nearly strip several of them. I drove up to a trans shop that was about 25 miles away and we replaced the nuts and properly torqued them on. So far, no sound. The trans shop said that the TC I bought is a "billet-backed severe-duty" unit, and that is shouldn't have any damage, but I am a little leary, as I have all sorts of problem with the tranny in this truck and previous TCs. Any suggestions on what to watch for to avoid any future trouble? Is it possible for a flex plate to be loose enough to make a loud noise and not damage the TC?
Cheers,
Nathan