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Discussion Starter #1
I've got a odd problem. The wife was driving home, turned onto our street and lost all power to the wheels she was able to coast home. She tried shifting to low ,2nd, reverse and the engine just revved. I tried to start it the next day and the starter engages the flywheel, but just turns the flywheel. The engine doesn't turn over. I removed the starter and was able to turn the plate by hand.? It appears to have a aftermarket transmission. We had issues 2 years ago also. The Flexplate/ flywheel was replaced because it was cracked. It was bending and making a racket.
 

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The flywheel on every engine I've dealt with (I haven't worked on any RAV engines) is bolted onto the end of the crankshaft, so it would appear to be a mystery for the starter to turn the flywheel without turning over the crankshaft and at least the pistons unless the flywheel somehow has become detached from the crankshaft, for example, if the mounting bolts have loosened and fallen out of their mounting holes. If that happened the engine would run strangely if at all. Perhaps a RAV engine expert can shine a different light onto the situation.
 

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1999 Toyota RAV4 with 3MZ-FE 6 cylinder engine, camo wrap, OME lift, heavily modded
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The flexplate is either loose because the bolt heads have sheared, the plate was sheared near the bolts and are allowing the drive plate to turn, the bolts have backed out (not usually possible because the bolts will contact the torque converter), or the crank shaft has sheared off (not likely either).

The flexplate is turning "true" because it is still bolted to the torque converter.

My bet is a broken flexplate, not uncommon at least on other vehicles.

Make sure when you replace it that the bolts are replaced, never reuse flywheel, pressure plate, flexplate, or torque converter bolts. Torque all bolts to the proper specs and tighten them like you do a wheel tightening opposing side bolts. Make sure everything is aligned properly a bowed flexplate will fail.

Picture of broken flexplate, not for a RAV4 but just to give you an idea - https://drive.google.com/open?id=0B0N4qdhM8CoaQU9JRWI2eTdPY28

The center bolt holes are for the crank shaft, the outer ones are for the torque converter.

The biggest costs if you pay someone to do it is labor, don't get a used flexplate unless you know it is a low mileage vehicle.
 

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Moved to correct forum and I agree a broken flexplate, but why? Especially since this is apparently the second time something must be misaligned.
 

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Discussion Starter #7
I can't understand why it went out again also. The mechanic that installed it asked me to check the cam shaft by pulling back and forth to see if it's moving. thinking that if it's worn and moving back and forth it's causing the flexplate to bend too much weakening it and causing it to crack/ break again. It that's the case he said a new engine might be the only fix. Any thoughts? Thanks for the answers just making sure I'm on the path to fixing it.
 

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1999 Toyota RAV4 with 3MZ-FE 6 cylinder engine, camo wrap, OME lift, heavily modded
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See this site for information about why flex plates break. AGCO Automotive Repair Service - Baton Rouge, LA - Detailed Auto Topics - What Causes A Flexplate To Crack

NOTE: When a flexplate breaks, it is important to find the cause. Simply replacing the flexplate will result in recurrence. Trying to install a heavier duty flexplate will normally pass the problem to the transmission. Correcting the cause of the misalignment is the only repair that will give permanent results. (ref: AGCO Automotive Repair Service - Baton Rouge, LA - Detailed Auto Topics - What Causes A Flexplate To Crack )

To determine crankshaft play:

1) Measure the endplay. Mount a dial indicator with the indicator in line with the crankshaft and touching the end of the crankshaft

2) Pry the crankshaft all the way to the rear and zero the dial indicator. Next, pry the crankshaft to the front as far as possible and check the reading on the dial indicator. The distance traveled is the endplay. A typical crankshaft endplay will fall between 0.003 to 0.010-inch. If it’s greater than that, check the crankshaft thrust surfaces for wear after it’s removed. If no wear is evident, new main bearings should correct the endplay.
 

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I didn't read the "What Causes" but "It appears to have an aftermarket transmission" certainly is suspicious especially since I didn't know they were even available.
Unless the engine and transmission are axially out of alignment the only way I could think the flexplate could have stress on it is by the torque converter putting push-pressure on the crankshaft via the plate. That could (should) be checked during installation. With the plate bolted to the crank and the TC installed on the transmission when the bell housing mounts to the engine there should still be enough slack that the TC can be rotated freely against the plate before they are bolted together. If not the plate will be subjected to constant deforming and cannot be expected to last. This would also wear the crankshaft thrust bearings as eodgator mentioned so excessive endplay would be another (disappointing) clue.
 
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