Engine/Transmission (1994 - 1998) Flywheel turns, front pulleys don't!

[Piston Slapper]

Anybody want to guess? Happened to my dad's truck today. He rolled on the throttle to pass a truck and truck made loud racket from under hood and just quit. He coasted about 1/2 mile back to his work. After getting back, coworker climbs under truck and says flywheel and torque converter are spinning when you crank it over put the front pulleys never turn! It makes a horrible racket too when you turn it over... .



I got my guess, but don't know what it is yet. Just thought we could play "Name that tune!"



P. S. I have only received the symptoms via phone. Haven't personally witnessed anything yet.



Truck Bio:

95 Auto 4x4

#4 Plate (centered)

370 Injectors

191 Delivery Valves

3GSK

ATS TripleLock TC

 

[BV]

I'm game - Broken crank.



Sounds like it's a money noise - Sorry

 

[Joe G.]

Has the KDP been fixed?

 

[gitchesum]

Let's just hope it's only the flywheel bolts.

 

[340Mark]

Odds are on the crank. It's just so big you would think it's indestructible

 

[Camara]

My dad had Diamond Reo trucks with Gold Comet gas engines and broken cranks were a very common problem. They usually broke between #4 & 5. Usually they ran bad enough to get them back to the garage. It was halarious - truck go slow but the fan goes like a son of a gun.

 

[Elite1]

My Guess, KDP strikes again!

 

[Piston Slapper]

The suspense is killing me. I can't wait to get it on a the rack and get the dust cover off! I'll keep ya'll informed. Starter is spinning and flywheel is spinning. Making horrible screaching noise. Can't feel anything on the front pulleys moving.

 

[Lsfarm]

I'm betting on:

I'm betting on the flexplate, it has the ring-gear and the torque converter is bolted to it. When the flexplates break, the center rips out and the crank stands still.



Greg L The Noise Nazi

 

[Snow man]

Im with Greg, flexplate is history.

 

[TXDSLSHOP]

I gotta know!

The supense is killing me! I am on the flexplate side as well! I would think wth the torque these monsters produce that it would be the weak link as compared to the crank breaking! Let's hope were right, I would hate to foot the bill for parts for a broken crank! Just my 2 cents! Jeremy.

 

[Bigramguy]

If it was the flexplate,or bolts,then you would still see the pulleys turning up front,and little or no movement from the flexplate or convertor.



If the pulleys aren't turning up front,then it's gotta be a balancer or crank problem.

 

[TXDSLSHOP]

I thought the original thread stated when cranking it over the flexplate and converter turn and the pulleys don't move! I could have misread it.

 

[Bigramguy]

Your right,I wasn't thinking. The starter is spinning the flexplate and convertor,but because the flexplate is cracked or broken,it won't turn the crank.



I was picturing it with the engine running,not trying to start it. If it was running with the symptoms described,then it would be the crank or balancer.

 

[Piston Slapper]

Just to tease us some more...



Dad got it home last night and got it on the rack then he got a phone call and had to leave. He didn't get to look at it yet. Can't wait to find out what it is! I for the life of me can't see that big hunk of crank breaking. One good thing though if it is the crank, pops has done said we are going to build it back BAD! Cam, pump, full transmission, the works! Now, I kinda hope it is the crank!



My guess was between the back of crank and the Torque Converter. Sheared, broken or fell out bolts on Fly wheel or Flex plate. I think the Flex Plate guessers are going to be right. I suspect now after talking to them/ya'll more the Flex Plate is... FLEXED!



I'll post as soon as I hear... He lives an hour and 1/2 away, we'll probably pull the transmission this weekend. Gotta get it fixed by Sept 5th for it's sled pull christening!

 

[GWHaley]

It seems to me that the engine wouldn't quit running if the flexplate broke-would quit moving and it definetly would make some ugly noises.

 

[Piston Slapper]

The engine did quit, that's what is throwing the monkey wrench in the whole scenario. I wouldn't think it would quit either if it was the flex plate. It is making horrible racket if you turn it over. the puzzling part if it was the crank it has to move something unless it broke just the back off of it. If a crank did break, one would think it would break at a journal or carriage. I just don't think it did break even know it seems that way. In order for it to die like it did it would have had to bind something up. That's my reasoning for the bolts coming out or breaking off the flywheel or flex plate. Something has the motor bound up. We'll find out this weekend. Godd thing this is a play vehicle. He has a third generation also that just collects dust mainly.



I'll be really suprised if 375hp broke a Cummins crankshaft! Thats like kicking over a oaktree!

 

[Bigramguy]

When you snap the flexplate,you lose the inertia effect the flexplate and convertor have,so it will usually stall.



The weight of the convertor and flexplate keep the engine turning between firing pulses.



It is also quite possible something did jam it up as well.

 

[Bseg]

Is there any relationship to the crank turning and the main fuel pump?



If so the engine would quit because of no fuel delivery.



If the flex plate rotates when the starter is run and the engine doesn't turn over then I would agree with the fact that the flex plate snapped off.



Another thing to look at is pull the valve cover and watch the valves. If you crank it and the rockers don't move but the flex plate is still turning then you will know it snapped at the plate.



One other simple suggestion, try to manually rotate the crank from the front of the engine and observe the flexplate to see if it rotates.



Good luck with this, hope it doesn't cost too much to fix.

 

[Piston Slapper]

Flex Plate...Flexed!

For all of those that guessed Flex Plate, well, it FLEXED. AFter pulling trans, it was in about 8-10 pieces. Stress fractures everywhere. That thing is puny! It didn't like that Torqueous Maximus!



Just ordered new "Double Plate" from Suncoast. Double means double strength.



I'll let ya know, should be here wednesday. I am sure we'll be sticking it in wednesday night.