Why does 1986 ford ranger keep breaking flex plates

that is huge pain , no? sorry it happens to you, really am.....
causes,
bolts missing holding it (end to end, or loose)
top cause. not set to torque spec. bolts.
a bad clutch TC can do it. or wrong one there, or was drop damaged.
some odd starter problem that has wrong tooth count on the starter? pinion.? making jam up cranking and each time overflexes the flex plate
or the flex plate if from cloners in china made from old beer cans.
buy only real TOY plate.
I call wrong parts or car or clones.
I call bolts loose.

possible incorrect pitch of the ring gear of the flex plate to the pinion gear of the starter
not all flex plates have the correct ring gear for the starter

1960 auto flex plate gee hard one

(Many/most Ford V8 engines are externally balanced from the factory)
keep trying
junk yards
a pontiac parts swap meet
a pontiac car club connection
an engineering shop to recondition your flexplate
or some company that can make a new billet flex plate for you


i guess you found only ones available off the shelf 2017 are
164 teeth 157 teeth 148 teeth

When you pulled your torque converter, did you remove the flex plate (some call it the flywheel, but that term is only correct for vehicles with a clutch.) I ask this because the Ford C-6 and the Ford AOD shared very similar design, especially when it came to the design and function of the front pump/torque converter and flex plate. The problem that is constantly found here is that someone unfamiliar with the flexplate on these transmissions reinstalls the flexplate, but with the wrong side facing forward. What this does is it forces the torque converter back a very small distance further and right into the front pump seal. In turn, this causes the seal to heat up and once the bearing race gets hot enough, that's the end of your front pump. This problem occurs after installing the flexplate in the wrong direction, finish bolting it all up and you try to test drive it. You first notice it is slow to shift, but after driving it for a few minutes, or running it while on jackstands, the transmission will give out completely. Even seasoned transmission guys have problems with this issue if they aren't being careful about what they are doing. I hope this helps you.

Check the gearbox alignment to the bell housing

need way more info ? is the torq converter braking the bolts ? are you doing the work yourself ? are you getting the correct flex plate . etc.etc.etc.

If the car is an automatic, it will have a thin metal flex plate, rather than a regular flywheel. If the flexplate gets a crack in it, it would cause a bit of noise. See if there is an inspection plate on bottom front of transaxle. Remove the inspection cover to look at the flex plate. Turn the engine over to view the flexplate all around. Look for cracks, maybe a loose or missing mounting nut where torque converter mounts on flex plate. If you see nothing, leave the inspection cover off, and run the engine and listen closely for a problem from that area.
Leaking oil, eh? Don't know if related, but while looking at the flexplate, check if motor oil is leaking out the rear main crankshaft seal. It will be fitted to the rear engine block, in front of the flex plate. Oil would be dripping off the rear of engine, or maybe collecting at bottom of bell housing, evident when inspection cover is removed.

If you look at the flex plate it might have a weight welded to it at one point. Flex plates are balanced before they are mounted to the crankshaft, so as long as the holes line up and all the bolts go in, your good.

the flexplate may not be sitting flush against the crank, or the crank may be out of balance causing a vibration and breaking the flex plate. try turning the crank by hand and feeling for any irregularities and look for signs of heavy wear on the broken plates.

absolutely a known issue...cracked flexplate...pull starter and inspect flexplate very carefully for cracks before installing new starter and thinking its a done deal