91Loyale had advised me on removing the outer TC/flexplate bolts, then pushing in the TC into the tranny to look for plate movement. Do you know if I can start the engine with them disconnected - with intentions of seeing if the sound goes away or worsens?

 

I am getting paranoid about this and would LOVE to determine that I indeed without any doubt have a broken or loose FP before I yank my motor out. (I was going to do this last weekend, but couldn't get a FP in time - omen?)

If the flexplate is cracked, you have to pull the engine.

 

If the knock is internal to the engine, you have to pull the engine.

 

I guess what I'm saying is that you're going to be pulling the engine no matter what, so get on with it!

 

I suspect you could risk major damage to the flex plate and TC by running it in the way you describe, but I don't know that for a fact.

 

Nathan

 

I suspect you could risk major damage to the flex plate and TC by running it in the way you describe, but I don't know that for a fact.

 

Nathan

 

no you can't run the engine with the flex plate unbolted from the TC. unless you have another way to start it.

 

the starter gear engages the teeth on the TC which is bolted to the flex plate and the crank. if you unbolt it, the crank will not turn when you turn the key.

 

the question you need to ask is, if not the flex plate, then what?

 

how bad is this "knock"?

 

what if you just drove it as is?

 

if it is internal it's cheaper to replace than to repair, generally speaking unless it is just valve noise.

 

and if it is the flex plate it will get worse over time, then you will know.

Edited May 13, 201015 yr by johnceggleston

Have never heard of or seen a car that has the starter ring gear on the torque converter but I suppose it works just as good as anywhere else.

 

If you keep driving it eventually the flexplate will break and you'll have your answer.

 

About the only way to get a visual check of the flexplate without pulling the engine or trans is to use a scope such as a Borescope stuck down into the bell housing to try and find the crack. So if you want to spend $1500 or so on a special tool, you can MAYBE do it without pulling the engine.

Have never heard of or seen a car that has the starter ring gear on the torque converter but I suppose it works just as good as anywhere else.

 

it's because auto trans subarus do not have a flywheel.

it's because auto trans subarus do not have a flywheel.

 

Right, they have a flexplate, like every other automatic transmission car out there.

 

But what you're saying is that the ring gear is mounted to the torque converter, rather than to the flexplate correct?

that's a huge job, i'd want to know for sure as well. pull the engine only to find out that it's not the flexplate.....well snap head, what to do then? is the motor hosed? was it something else? pull the heads or get another motor? best to make sure if possible what it is or at the very least for sure where the noise is emanating from.

 

what JCE said, can't start the car with the flexplate disconnected because the starter gears are "trans side" on the torque converter. that's a nice thought though to disconnect it and try that. not sure what you could look for but maybe it might show something still.

 

i know this has happened to a few folks and i'm wondering if you have gotten an idea how/where they tend to crack? my guess is the failure mode is very similar every time, this would help if you wanted to look into it further. but i haven't seen it myself yet.

 

the ring gear is mounted to the torque converter, rather than to the flexplate correct?

yep, that's it.

Undo the flexplate to converter bolts. Push the converter all the way back. Undo the 4 engine to trans nuts and bolts. Seperate the engine and trans. You'll probably have to pry them apart on an older subaru. They will split a good 3-4" apart with the engine still in the car on the mounts. That will give you a good look at the flexplate. The flexplates usually crack around the bolt holes. Sometimes they crack all the way around and the car won't start.