Have a 1968 El Camino with a 350 engine and 350 automatic. When it warms up it starts to squeak, even with the transmission in park. Disconnected fan belt and eliminated water pump and alternator. Probed power steering pump (new), distributor and other components with a stethoscope, but all sounded fine. The noise is loudest under the car. I used a piece of vacuum hose and the noise appears to be coming from the flexplate/crank area. I did confirm that the flexplate is not rubbing on the starter gear. Someone on the Chevelle forum suggested that the flexplate sometimes cracks around the crank hub mounting bolts. Anyone know how to comfirm this besides pulling the transmission back and pulling the flexplate? I'd like to make sure this is my problem before doing all this work. Any suggestions would be appreciated.

The ONLY sure way is to pull the Trans. (Unless you know a real good Psychic):dontknow:

Can you remove the flywheel cover and look with a borescope?

".......Can you remove the flywheel cover and look with a borescope? ........"

That might work, but to really check, you would still need to loosen the torque converter and slide it back to check for cracks between the bolt holes.

I kind of agree with the diagnosis of a cracked flex plate by the way.

Back when I was working flat-rate the trick I would use for a flex plate replacement was to support the transmission from the rear with a transmission jack or in a pinch a floor jack. Place another jack under the pan (just enough to support the engine) and remove the crossmember, drive shaft, inspection cover and remove the torque converter bolts and slide the converter back.

I would then remove the bottom bolt on each side of the bellhousing and replace them with 6 to 8 inch long bolts. Next remove the rest of the bellhousing bolts and then carefully slide the transmission back to the ends of the long bolts. There is normally enough flex in the cooler lines speedometer cable, and even shift linkage to let it slide back. It’s tight, but you can normally then get to the flex plate bolts with a long wrench.

The biggest problem replacing the flex plate is often just getting the holes indexed correctly but if you make a chalk mark at the bottom the old flex plate before you pull the final bolt it’s not too bad to get the bolts lined up. Once the new flex plate is installed, just slide the transmission back and bolt everything up.

If I was working alone this normally let me cut about an hour and a lot of aggravation off the job.

The cover is already off, but I don't have a borescope. I like the idea of using the long bolts as a guide this should really save time - thanks for the tip.

If you really think it's cracked, don't wait too long to find out. If the crack propagates enough , you may have some damage to fix.