HELP! Trucks on the side of the road

[BCarmicle]

Alright, here's the story. I was driving along last night and wanted to see how much boost the truck would make, so I floored it once and everything was fine. Then I floored it again and heard a sound that wasn't normal. Each time I floored it it was dropping down to 3rd gear and running that gear out and then shifting to 4th. When the truck shifted into 4th on the second time it just rev when I pushed the peddle and something was making a bad sound. I pulled the truck off the road, let it cool down and shut it off. At this point I'm worried I've really screwed something up. I try to start the truck and it won't turn over and makes a bad sound when I turn the key. I got out and look under the hood and truck and didn't smell anything or see anything leaking and everything under the hood look normal. Had to leave the truck on the side of the road and getting it towed in to a mechanic's shop to get it checked out. The mechanic said it could have been a flex plate that broke. I thought it might have been my head gasket. What would happen if I blew the head gasket? If the flex plate broke what would have happen and what else could it have hurt? What do you guys think? Any advice or opinions would help. Thanks.



Brandon

 

[GWoody]

Is the bad sound like a grinding noise, if so, I would suspect flexplate, I can't see a blown head gasket keeping the engine from turning over, how much boost were you making.

 

[BCarmicle]

I honestly can't remember if it was a grinding sound or not, I just know it wasn't normal. When I put it to the floor it I saw 65lbs. of boost.

 

[GWoody]

"I pulled the truck off the road, let it cool down and shut it off"



How long did you let it cool down? If the truck sat there and ran long enough to cool down and the engine sounded fine then I would really have to beleive it is something to do with the starter portion of the flexplate, I can't even imagine the flex plate being broken and sitting there idling and sounding fine.

 

[John - K5AWO]

Originally posted by BCarmicle

When I put it to the floor it I saw 65lbs. of boost.

Hate to say the dreaded words, "when you play, ya gotta pay".



65 psi boost? That's about 20 psi more than most folks are willing to do without upgrades to the head, head gasket (0-rings, etc... )



You were in danger of pulling the head stud bolts.



My guess is at the moment, your current problem is a broken flex-plate on the transmission. The pieces are now jammed against the case and preventing the crankshaft from turning.



I am $ure your mechanic will pre$ent the "good" new$ real $oon.

 

[BCarmicle]

Originally posted by GWoody

"I pulled the truck off the road, let it cool down and shut it off"



How long did you let it cool down? If the truck sat there and ran long enough to cool down and the engine sounded fine then I would really have to beleive it is something to do with the starter portion of the flexplate, I can't even imagine the flex plate being broken and sitting there idling and sounding fine.

I let it cool down to were EGT's were about 280 degrees. I think it sounded fine at idle but had a bad sound when I revved it. Its hard to remember, this all happened at about 2:30a. m.

 

[BCarmicle]

Originally posted by John - K5AWO

Hate to say the dreaded words, "when you play, ya gotta pay".



65 psi boost? That's about 20 psi more than most folks are willing to do without upgrades to the head, head gasket (0-rings, etc... )



You were in danger of pulling the head stud bolts.



My guess is at the moment, your current problem is a broken flex-plate on the transmission. The pieces are now jammed against the case and preventing the crankshaft from turning.



I am $ure your mechanic will pre$ent the "good" new$ real $oon.

I've got ARP studs in. I was going to try that and see if it would hold since the 3rd gen heads are stronger than the previous models.

 

[Idaho CTD]

Brandon,



Are you all billet in the transmission? If not it sounds like either a flex plate or it could be a shaft but usually they break under hard launches not when you are up and running. I would suspect it is a flex plate first though.



Nathan

 

[BCarmicle]

All shafts are billet. Looks like theres a good chance its the flex plate. IF the flex plate breaks, does it destroy anything else in the transmission?

 

[ThomasLawrence]

IF the flex plate breaks, does it destroy anything else in the transmission?

Usually not... it's just bolted to the outside of the torque converter. Pull the inspection cover on the bottom of the bell housing (two small bolts), and see if you can wiggle the flex plate/ring gear around. If so, you've found your problem. If you see fluid in there, then you do have a problem, because the shrapnel from the flex plate probably sliced into the TC.



Now... 65psi on a DD Jammer??? Are you TRYING to blow it up?



-Tom

 

[BCarmicle]

Originally posted by ThomasLawrence

Now... 65psi on a DD Jammer??? Are you TRYING to blow it up?



-Tom

65psi with a DD Jammer and a B2. Guess I need to update my sig.

 

[GWoody]

BCarmicle



Where you at, did you figure out what was wrong with the truck???

 

[BCarmicle]

Yep, problem solved. It was the flex plate that broke. Now I have to find out if it hurt anything else in the transmission. I going to look at the truck and flex plate today but my mechanic said he is going to have to pull the transmission to check if it hurt anything else. Is there a better way to check or does the whole transmission have to come out?

 

[GWoody]

Dang, I been thinkin about a DTT and when I spoke with them they really didn't recommend their heavy duty fp, said the stock ones were plenty strong. Course I ain't plannin on twins or 65 lb. of boost. Brandon, let us know what caused the failure, if you can tell.

 

[Pirate4x4]

Yeah, hurry up and tell us what caused the failure! I have my motor out my truck right now, but it's going back in tomorrow!

 

[GWoody]

Dang, I been thinkin about a DTT and when I spoke with them they really didn't recommend their heavy duty fp, said the stock ones were plenty strong. Course I ain't plannin on twins or 65 lb. of boost. Brandon, let us know what caused the failure, if you can tell.

 

[BCarmicle]

I guess what caused the failure was the power. I don't have the strongest truck on here but I have about 1200ft-lbs of torque and I guess thats what caused it to break. My mechanic agreed with me on that, that power just caused it to break. Before I put the twins on I could here a noise when I let off the throttle, the noise sounded kind of like a clang. I talked to DTT and they said it could be the flex plate bending. With a single turbo I was at 511hp and with the twins I'm at 569hp. I had been running the truck with TST on 3/3 and I floored it and it made 65psi of boost. Then I turned it up to 5/5 and floored it and it made 65psi of boost(thats where the wastegate was set at) and the flex plate broke. So the flex plate can possibly break if you have the power. But heres the catcher. My mechanic spoke with his friend that works for Cummins and he told him that flex plates on the 3rd gens are breaking even without high hp. I will have more info when we pull the transmission tomm.



Brandon

 

[BCarmicle]

Good news. The torque converter and everything else in the transmission is still in good shape. Only have to replace the flex plate, dowel pins, and a seal. Besides for the 5 days of down time everything will work out pretty good and gives me a chance to put in a new VB.

 

[Bob Wagner]

Is Olee doing the work?

 

[BCarmicle]

No, I tried to get ahold of Olee but didn't have any luck. A guy a little closer is doing the work. He and his friend that works for Cummins is taking care of it.