crankshaft problem

[LowellR]

i have waited about a year now to purchase a very clean 93 one ton from the original owner. it has about 100,000 easy miles, extended cab, auto. recently the owner heard some type of noise from the transmission area and brought it to the local ford dealer. this is a small town, no dodge dealer. i personally know the mechanic who worked on the truck. what was found was that the thrust bearing was worn enough to let the flywheel contact the block, hence the noise. has anyone ever heard of this on an engine with what i consider to be low milage? they are going to change the main bearings and the flywheel. any info or opinions welcome. thanks in advance.

 

[paccool]

This may be a new one! I have not heard anyone discuss this before. Let us know what they find when they get it apart. There are lots of rigs out there that have way more than 100,000 miles without any problems.

 

[A Johnson]

Weeeell, beins you asked for opinions, I'll offer mine.

The key word was auto transmission. I would say somthing let loose in the transmission and forced the tourqe converter/ flywheel forward. I have seen this in midrange trucks using Allison transmissions. I'm not sure what the problem is but maybe some of the transmission experts will take over.

 

[mark93]

Whoa, whoa, whoa! The what did what to the what?



Go down to the dealer and look for yourself before they tear the engine apart. This is something I would have to see to believe.

 

[JLEONARD]

That happened to a VW diesel I had a few years ago, but it was a std trans. Somehow the thrust bearing got overloaded and the counterweights on the crank were hitting the main bearing caps.

Made a really funny noise. The crank had easily 1/8" endplay (should have been . 015" max).

Only had 175K on it.



That was good thing though. . made me ditch it and find a CTD!

 

[Power Wagon]

I have seen a couple engines this happened to. One was a 6. 9 or 7. 3 Ford. The complaint was poor economy and power, not noise. When you started the engine, and put your foot on the clutch, the front dampner would move forward. This would change the valve and injection timing. It was quite unstable, to say the least. We showed it to the owner, who then got real depressed looking and drove it away. I have no idea what became of it.



If only the bearing is trashed, the engine can be pulled and a new set of bearings put in, and you'll probably get a lot more miles out of it.



As was suggested, it would be a very good idea to try to determine what caused the failure in the first place. Excess thrust on the crankshaft is the first place I'd look.

 

[LowellR]

thanks for the replies so far. i'm off tommorrow and will try to get more info. you guys are thinking the same as i am, what caused this.