What Happened??

Purchased a charger, Not running, Thought it had thrown a rod...because it would turn over so far and then clunk..

Pulled motor and trans out, here is what isleft of Flex plate.

So What could have done this? with the flex plate off motor it turns over with no restrictions...

Sometimes stock flexplates just give up. I made one look like that in a 340 Swinger once.

Bolts might have loosened up or some such thing.

With the amount of leaking fluids I would give good odds that the bolts came loose.

OE flex plate bolts have thin heads so they clear the back of the block.

What bolts were in it?

Check the rear webbing of the block for damage / bolt head scrapes.

all bolts still tight in torque converter.

Wow! Got rusty and weak I guess????

Maybe through it into reverse at 60??? Who knows?

With the direction of the tearing of flexplate, it almost looks as if the converter locked in place some how?

Was the shifter in park when it died?

Any flat spots on the rear tires?

Are the locator dowl pins in the bell housing. Misalignment can cause a flex plate to fail

more than a few too many neutral slams

That's my thought too.

Agreed,
I broke one like this in my plow truck in 1979 blizzard.

Seen it before.

I had a Ford come into the shop years ago.Changed oil went to start and nothing after a large clunk.The flex plate just broke.Didnt look that bad but it snapped off completley.New plate and all was well.Oh yeah the motor and trans had never been apart.Rocky

one pin only I was not driving the car,,Purchased it non running. webbing looked ok on back of engine found one bolt in flex plate loose?

Dilemma: do I just get another flex plate and bolt back togather or send in tranny? OR rip down motor? have pan off all rotates good. Not the #'s motor for the car so could switch out

154800 is car vin

the car

Put a plate in it and start it up. Not the first one I've seen break. I personally have had 2 do this. Replaced the plates and never had another issue with either car.
Doug

You might get by with installing a new flex plate (and new bolts) and driving it, but my luck is the trans will die in short order. Since the trans is out, I'd send it in for a rebuild. The possible neutral drop cause for the damage flex plate, and the visual appearance of the trans itself would warrant a rebuild in my book.

Other then the normal motor concerns with buying a car like this, I would not have issues with the motor. It was hanging up on the broken flex plate, once that was resolved, the motor turned over OK. Gene

Does Joe Dirt have a relative living up in the Dakotas?

I wish you well, Chargers are not to be wasted.

If you get tired of it, I've got a farm somewhere up US 52 that you can haul it to.......

R.

Could be that is was cracked for a while and someone kept driving and due to time and vibration it busted out the rest of the way in one swift bang.

I agree with sending the trans for a check, at a minimum pull the pan and look for metal parts, 727s aren't bad about showing material but you should get an idea by the smell of the fluid and any metal in the pan.

This , I have no idea how a neutral drop is responsible for that ???

There is no HARD mechanical connection between the back of the crank and the mainshaft of the transmission , total FLUID coupling inside the torque converter .

Neutral drops will only affect the trans internals , drive shaft and the rear end.

The many hours of running with that misalignment because one dowel pin was missing is what crack and ultimately broke that flexplate.

I'd be looking at the convertor snout and the bushing in the front drum for wear, along with changing the front seal.

Post up a picture of the converter snout ...

That's a fairly common failure on the early Cummins trucks. I've seen a cracked plate on a gas engine too.

I wouldn't be overly concerned. Someone just let it a cracked one go to long and it finally failed.

x2. You should have two dowel pins - and you'll need the 2nd one when you put that back together... Unless you want another broken plate.

Make sure both locating dowels are in the back of the block

where do you get those dowels or do u just get one out of another block?

Found out the car had been Towed on car Dolly from Washington state to North Dakota...The drive shaft was NOT removed

That didn't cause the flexplate to break , but with that knowledge I would be going thru the trans. Pay close attention to the mainshaft surface that rides in the rear support and the rear support itself.

The pump is not in the rear of the trans. Shouldn't have mattered should it?
I'd agree its a good practice to remove it especially when going that far...but it could've never done that damage...
I believe the missing dowel is the reason for the damage...

Typically flat towing w/ the driveshaft left in is limited to something like 35 miles at fairly low speeds. I wouldn't chance it, I'd go through the transmission before attempting to install it. 2¢

Robert

You need both dowel pins. That top hole looks a bit oblong, like the trans case was moving?
With the transmission apart, you could even check the run out to the trans pump housing in the case and correct it if needed.
For offset dowel pins:
http://www.robbmcperformance.com/products/dowels.html

I would go through the trans and rebuild it. If your mechanically inclined, you could do it for $100-200 depending on the quality of parts used.

GREAT Thanks for info and Link!!

PHIL,YOU HAVE MOPAR'S BIGGEST LOW STALL TRUCK CONVERTER. UPGRADE TO A BETTER/SMALLER CONVERTER/FLEXPLATE WHEN YOU REBUILD YOUR TRANS. THAT THING IS PROBABLY FULL OF TRASH ANYWAY. YOU'LL WANT A NEW CLEAN CONVERTER FOR THAT CHARGER. NICE CAR.

Correct diagnoisis🔝.

It happens quite often from storing the block on the floor with the dowels pointing to the ground.

Since the are tapers they need to be pulled out so more than the taper is engaged to the transmission holes, which also have a lead in.

I had a cracked flex plate on my 72 duster. I put a new flex plate on and three weeks later it broke again, so I knew I had a probelm. I was told the torque convertor (front punp) bushing was worn out, which caused the convertor to wobble and crack the flex plate. Replaced the bushing in the front pump and the convertor. Probelm solved.

Thanks for all the input: I am going to replace torque converter and get dool installed have not took pan off the tranny yet to see what it lloks like..

Hard to really see the condition of the converter snout in the picture, but in my experience missing pins or a mis-aligned bellhousing will usually junk the front pump bushing and converter snout far before it would break the flex plate.

So with that said, I would at least change the front pump bushing and seal if you don't go through the whole trans.