Torque converter loose bolts

[CampoCougar]

For the past several months, there has been an annoying rattle in the lower engine area of my '95 Seville.
It became worse over the past few weeks. My first thought was a bad main or rod bearing as the noise seemed to be in the lower engine.
Some people suggested possible bad flex plate or torque converter. A local trans shop estimated $1,500 to replace both.
However after close inspection and some honest advice from a GM dealer tech, I found the four bolts holding the torque converter to the flex

plate had loosened quite a bit, causing the torque converter to rattle and the loose bolt head to slightly contact the trans housing causing.
I jacked up the car, chocked the rear wheels for safety, put jackstands underneath the front, and layed on the ground.  I first removed the front

02 sensor, then the exhaust plate brace  from the oil pan (four bolts, one minute to remove) and the cross bar in front securing the trans and

engine (one bolt on one end, a nut only on the other sharing the motor mount, 2 minutes). I then had access to remove the bottom trans

dust/flywheel shield, which gave me fairly easy access  to the four torque converter bolts, using an 18 mm socket and swivel from the side.  I

removed each one, cleaned it and applied thread locker, set them back into the hole with a swivel socket and final torqued them with an 18mm

combonation wrench. I allowed some time for the thread locker to dry before starting. Bingo !!!! Noise gone.
Lessons learned:   the bolts can easily be accessed from underneath, trans removal not needed. While in there, the flex plate can also be easily

inspected for the dreaded cracks ( a known GM problem).  Third, is that you can also see very clearly if rear main seal is leaking (mine was

only slightly, then stops). Perhaps the most important lesson is that this noise can be deceiving. Before tearing the engine apart or listening to

bad advise on the engine rods or mains, or trans needed overhaul, just take some time to check out those bolts on your own. If they are even a

slight bit loose, they must be tightened.

[Bruce Nunnally]

Nice detective work & fix.  Odd that they would be loose.  Do you think the Seville has ever had work that would have involved those bolts?

[CampoCougar]

It has what appears to a be a replacement torque converter. I've had it for three years, and had bought it from a lady who just "had transmission work done". Maybe they did not use thread locker and they loosened over time. There is some controversy over using thread locker on fine pitched threads. I say use it; cheap insurance and it won't hurt anything.

[rockfangd]

Glad you resolved it before anything else could happen.

They do come loose and even shear off sometimes.

And GM is known for cracked Flexplates between the holes. I have seen them break right off.

Mainly on trucks though.

Welcome to CaddyInfo

[RubberCarrot]

Nice troubleshooting!  I love to see a "victory"!  Cruise on!