Flexplate bolts tore out of crank?

[jaws5991]

I bought a 1995 stepvan with what i was told had a bad motor. I removed the 6.5 diesel and in doing so found two things, 1 the bellhousing around the 4l80E were all broke but one, 2 the flexplate was busted and only one bolt was halfway holding it to the crank. I assumed the engine had caused this when it failed. I swapped the 6.5 for a 6.2 I received for 300.00 using all the original motors top end and swapped the guts in the transmission to a new case. I bolted everything up and it purred like a kitten for a half hour. Ran the truck back and forth, drove it around the parking lot and put it in park. It idled for a minute then the power went down and the thing sounded like it would fly apart. Pulled the flexplate cover and could see it did the exact same thing as the original motor. I now assume it had a good motor and that the problem is in the transmission. More specifically I am questioning if it is the torque converter. Has anyone ever had this problem and do I correctly assume it is the torque converter? The flexplate bolt holes look oval now and the bolts to the crank are all coming out at an angle, though not all are even in still. I can see all this with just the flexplate cover off. Any help would be greatly appreciated.

Someone else has suggested that the injector pump lines were put back wrong when this guy I bought the truck from had a new pump put on. Will that cause this to happen to the flexplate? Any answers are greatly appreciated.





1995 Chevrolet stepvan with a 6.5 diesel, 4L80E, Tommy lift.

[DmaxMaverick]

Welcome aboard, Jaws!

Sounds like a bad torque converter. It could also be the tranny input shaft (might be now) or the input bearing, but that should be fairly obvious as soon as you try to insert the TC. As a last stretch, it could be a broken crank, cause or effect.

[jaws5991]

Still looking for help or thoughts on this situtation. Any thoughts are appreciated.

[jaws5991]

New information:

The guy I bought this truck from said; mechanic says fuel is getting into the oil so mechanic put in new injector pump, still happened, mechanic put in new injecters, still happened, mechanic says a push rod bent, so mechanic replaced and it ran until real bad noise came from bottom, mechanic says bottom end is bad on motor and then I buy truck. Then I find flexplate tore up and replace engine with parts from original motor. So we are kind of hung up on what the original problem might have even been.

[DmaxMaverick]

The harmonic balancer and/or crank pulley might be part of the equation.

[jaws5991]

Thank you DmaxMaverick (http://www.thedieselpageforums.com/tdpforum/member.php?u=3239)

We are still looking for more thoughts and will post results as we go along.

[DmaxMaverick]

Good luck!

Your situation is rather unique. Getting others to respond isn't always easy. They either agree with what I posted, and don't care to state so, or they don't have a clue. It is possible someone has the answer you are looking for, but just hasn't read this yet. Give it some time. Unfortunately, there's no way to prod anyone into responding. Your first post today may be helpful, as is any details you can muster up. You have gremlins at work, and they can be evasive.

[More Power]

I agree with DM, in that the TC would be high on the list of possibilities.... but you should have heard/felt something before it fell apart. A bad TC should produce clanking or other balance issues if it's causing this problem.

Install a new flexplate, and new flexplate bolts installed with thread locker and torqued to 65 ft/lbs. Then run the engine without the TC or transmission bolted up.

Jim

[jaws5991]

Thanks MP we will start there this weekend, in the mean time everyone still feel free to throw your two cents in.




1995 Chevy Stepvan 6.5, 4L80E, Tommy Lift

[jaws5991]

Rethreaded crank bolt holes, Used longer bolts, made sure all were the same, tightened new flexplate to crank at 100 pounds, new torque converter and new to me used transmission. Runs great. Drove it 500 miles home the day after we put it all back together in 8 inches of snow. Wasn't 100% sure of the problem so we did it all. Used plenty of lock tight as well.