Flexplate/Torque Converter movement

[Broken_down?]

So I have had this slight banging noise for awhile. I thought I had a cracked flex plate but today I got under and the Flexplate/Torque Converter (bolted together) move forward and backward about ¼ inch. There should not be any movment right? Does this mean the bearing by the crank shaft is shot?

-rich

[dave2953]

Are the flexplate bolts tight? It's nearly impossible to get a wrench on them with the TC installed. The flexplate itself shouldn't move. The TC pushes against the flexplate and it flexes. If the flexplate is cracked/broken, this is probably the noise you are hearing. Did you check around the flexplate bolts for cracks?

[Broken_down?]

Yeah I looked for cracks. Could not find any. I replaced the flex plate about 1 year ago. It started happening shortly (1 to 2 months later). The tranny was in Park. Does that make a difference in wether it should move or not?

[cfoust3]

Man, I just went through this to, I looked at everything on my '68 could not figure out why it was moving. Everything was tight, I eventually gave up and took it to a tranny shop near my house and they tore into it. Long story short, the problem was my torque converter was out of balance. Causing everything to move, they said something inside it broke (can't remember the exact terminology they used) They replaced it and now no more noise, and actually alot more power now. Best $200 I spent this winter.

[Broken_down?]

While I was looking for the block casting #'s I noticed a bell housing bolt was half way out and the middle one was missing completely. But this would not cause the tranny to vibrate would it if the rest are in place?

[rage'nrat638]

sounds like the flex plate is broken around where it bolts to the crank. the flex plate should not move back and forth
at all.
or do you mean up and down? don't sound very good either way

[Broken_down?]

No up and down motion. I tryed to see if it would do that but won't. It does move ¼ forward and backward (foward towards engine backwards toward the rear). The flexplate and troque converte move as 1 unit. i'll see if I can get ashort video clip so you all can see it in motion.

[RACINJASON22]

Sounds like the thrust bearig face could be shot on the crank. It's the only thing I can thik of. Try to see if the harmonic balancer moves when your moving the flex plate. Have some one watch for you. Hope this isn't your problem though. I'll cross my fingers for ya. RJ22

[Broken_down?]

it moves .......(Long Pause)....(Lots of swearing) I guess time for a complete rebuild?

[rage'nrat638]

yea so it sounds like the thrust bearing holding the crank in place is shot. not a good thing..better to catch it now before it bends piston rods or cracks them or trash's the trans pump..

this movement can hurt a lot of things

[Broken_down?]

Knowning that I have to rebuild the engine, when I go to buy a new engine rebuild kit do I need to buy the pistons also? Shoud I replace them anyway? When cleaning the cyclinder walls does that bore them then causing me to have to buy some special size pistons? or can I just get a stock rebuild kit and use that? Any help is great.


Rich

[rophle1]

When you tear it apart, you'll have to look at the condition of cylinder walls and pistons. If walls are scared up then you'll want to bore it a little which will make you buy a bigger piston. Since you've had some movement, make sure you get the crank inspected at a machine shop. Hopefully you can get by with just polishing it.

[RACINJASON22]

Broken down? 1/4" is a quite a bit of movement. I would do as roplhe1 said and have things checked out good before ordering any parts. Not wanting to be the barer of bad news, but the last time I had a crank shaft move this much the block was ruined also. RJ22

[Broken_down?]

I have my Dad comeing down to visit and he wants to tear it down and see whats going on. I am praying it is not ruined.... Wish me luck! PLEASE!

[Broken_down?]

With that much movement wouldn't you see some metal shavings in the oil?? Case there are none.

[RACINJASON22]

I would think there would be some tell tell sign but I have seen weirder things. And the best of luck to ya on every thing. RJ22

[Pl4yboy]

My fingers are crossed for you too!

[WorkinLonghorn]

I'm just curious. What did you and your dad find out when you tore into it?

[Broken_down?]

Well sadly it had more movement then was acceptable....... Had no play up or down or left to right. But forward and backward...shot. What caused the problem was the main bearing not getting enough oil up I guess. (Main bearing? I think that was it or some bearings anyway.) Did not damage anything though thank god. The flex plate was not cracked and nothing had seperated from the back of the motor. So know I am looking for a 350 I can throw in there and have my truck back. We are going to have the 69' 350 Vet engine the truck has currently rebuilt. Thanks again for all th help guys. You all rock!