Tcole_024

Posted yesterday regarding an intermittent knock sounding like a cracked flexplate. Turns out the flexplate is cracked again. It was replaced last year around this time, and now it's cracked again. Any idea what else is going on that's causing this? Thanks

andrewmp6

Did you use a good one or a cheaper brand ?Did you torque all the bolts to the said foot pounds?

Tcole_024

bolts were all torqued to proper spec, I used an Omix-Ada flexplate which I thought was pretty decent.

CCKen

Where are they cracking, around the crankshaft mounting flange or at the bolt holes?

Tcole_024

3 long cracks around the mounting flange and also some small cracks around the bolt holes.

Tcole_024

Some Guy

I repaired a full size blazer years ago with same problem. Owner changed cracked flexplate, and it cracked again within a few months. I found a wire loom bracket pinched between bellhousing and block. Also changed t case crossmember bushing. Seems to have fixed it for him

Tcole_024

Bump

CCKen

When you changed the FP did you make sure the backing plate was in place when installing the FB bolts (see pic), and that they were torqued to 105 ft/lbs in a staggered pattern (see pic)?


Did you happen to notice if there was any forward and aft play in the crank shaft (Thrust Bearing wear)?


Of course, all four bell housing to engine block torqued to spec.

Tcole_024

Not sure if there is a backing plate on mine actually...do you have a pic of just the backing plate? No thrust bearing wear to my knowledge when I checked it.

CCKen

The backing plate is in the above pic, it's like a giant washer under the heads of the bolts. I don't have a pic of just the plate.


Here's the parts catalog listing for it, item 26.

Tcole_024

That helps a lot! Guess I won't know if I'm missing the backing plate until I tear into it but that seems like it could be the culprit for my FP issue.

CCKen

Maybe [?]