flex plate again
 

I hear flex plate noise again after replacing it about 30000 miles ago. Has anyone figure out what causes the cracking? I now hear it all the time after a mildly agressive driving escapade.

It's possible the engine/tranny were not lined up properly during reassembly last time. Can you confirm for sure that it's the flex plate this time?

Check for aligment pins between the engine and tranny.

Hi mate yes anything that causes the crankshaft, mainshaft to bend out of line , flexes the plate. Bad engine, gear box mounts, can allow the engine/box unit to bend as the car bottoms over dips at speed. I would check bell housing bolts and mounts.

If all else fails,,,,,,,,,,,,,, back to the Jensen.:)

Harvey;)

I see there was a service bulletin on the transmission front bushing wear. Things to check were cracked flywheels and worn torque converter pads. I didn't think a automatic car had a flywheel, so I suppose they are talking about the flex plate. Wear in the crankshaft can be a culprit. I did just have the front crank pulley replaced due to a little wobble. Maybe there is some extra vibration in my engine. I presume the pulley has a vibration damper built in as I don't see a separate one. So I will check the converter, crank, alignment pins, and gearbox mounts.

you got me wondering..
 

I have a lot of noise from down under when I first start off with light acceleration. I had been thinking that it was just the exhaust. But now you all have me wondering. Can someone tell me of just how and what to check to verify that it is or isnt a flex plate issue? Thanks..

Chris.

Use a long screwdriver to your ear as your stethescope and probe around. I didn't have the sound at idle, the car had to be in gear and a driver step on the brake so that there is a light load on the engine. From under the hood, access to the bell housing area is still adequate that the noise will be loudest there when you touch it with the screwdriver.

The alignment pins can't be seen unless the tranny and engine are pulled apart. I don't know for sure if the pin hole goes all the way through a flange so that it's presence can be checked. There was someone awhile back that was eatting flexplates. It turned out that one of the alignment pins was missing.

The transmission just got removed for the flex plate. Alignment pins were fine. The rear transmission mount was broken, but the mechanic says that is pretty common without also seeing cracked flex plates. We will see if a Legacy one fits. It has more holes so is more flexible. We will only install it the next time around. This time, it gets new stock again. The first flex plate was changed with the trans at 110000 miles, the 2nd plate changed at 140000 miles, and now the third at 186000 miles. Guess I will have to wait another 40000 miles.

You may want to check the centering alignment of the TC inside the crank shaft. Something is not right. Any dents or dings in the engine/tranny mounting faces? Slop in the pin holes?

So the flex plate was definately cracked?

Oh, yes. Multiple cracks.
The mechanic says crankshaft play is .012 which is a bit out of spec, but ok since the seals front and rear are still sealing and much better than other Subaru engines with this many miles.
There was a design change on the Legacy flex plates. We are trying to figure out if the SVX engine should have had a change but never got it as it was out of production.

Flex Plate
 

Hi all,
There was a TSB on the flex plate. They were breaking even when everything was lined up due to bolts improperly torqued and/or insufficent thread locker. These are the ones that attach the plate to the crank and the 4 that the converter bolts to. I would reccomend having a mechanic check the torque on the converter mount bolts which are accessable by removing the rubber timing cover on the bell housing if there is a noise. Also, I would replace these bolts anytime the plate is removed. (many manufacturers reccomend this) It may be overkill but hey, I'll pay a buck a bolt for piece of mind.

NiftySVX

The job is done. No charge except for R & R of a broken transmission mount. I am pretty happy on the financial side. The Leagacy flex plate could work. It is about 1/16 thicker than the SVX but it has more "flex" holes. If I have a problem again, we will probably try the Legacy.