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Discussion Starter #1
Ok,day was going well,started at 3:00 am,and was installing my 2002 5.7 motor and trans.
I thought I was pretty much done,but no.
The flex plate from the 2002 motor doesn't line up with my earlier turbo 350 torque converter.
I have another available,external balance from a 91 5.7.
When did they change the bolt pattern on the flex plate?
I was under the impression all external balance flex plates had the same bolt pattern.
I've never read or heard of anyone not being able to bolt on their torque converter.
Any help appreciated.
Thanks.
 

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We had the same problem with a 496 flywheel yesterday that wouldn't bolt up to a turbo 400 converter and don't know why either :dontknow:
 

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87-99 V8 gm flexplates interchanged, they were on the one piece rear main seal motors, they were different than the earlier two piece seal designs. after 2000 they changed the flexplates again...
i believe they make an adapter to couple the late model motors to earlier transmissions
 

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Discussion Starter #4
I have another flexplate I matched up from a previous motor I was considering using.
It was full of sludge,so I junked it and kept the useable parts.
It had a 700R4 trans,and was externally balanced like the motor I'm now working on.
Both are small register...they just have different torque converter bolt patterns.
The motor I'm working with now had the 4l80E.
The only possible solution is multiple flex plate styles...Just thought everyone should know.
I've never heard of the flexplate not matching up.
 

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The motors with one-piece rear seals take a different flexplate. There was probably a good reason for it, at the time.
 

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Discussion Starter #6
Both motors are one piece rear seal...and they both had different flex plates...although one had the 4l80E transmission,and it's the one that doesn't work.:beer:
 

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the engine you are useing may only had 1 trans option unlike the earlier motors. couldnt you just transfer punch the holes into your new flexplate and drill them. i did this on the one i ran into.i bolted the 2 flywheels together by the holes that did line up and drilled the needed ones.
 

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Discussion Starter #8
I believe the balance would be off.
I just separated the trans enough to swap the flex plates.
Ran a large bolt through some extra holes to keep the engine from turning.
Usually torque converters have captive nut.
The one I'm working on has very short nuts and bolts.
Besides using thread locker,what are the safest nuts to use.
Thanks.
 

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Torque converters are balanced independently. The flex plate won't fit the crank but in one position. If you have the correct flex plate for the engine do like CCC suggested. No problem drilling the new holes. The hub in the center of the converter supports and centers it. Have drilled many to adapt to different converters with no problem.
 
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