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Old 07-09-2005, 07:22 PM
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busted flexplate

so here is the set up.

caddy 500 in a truck with a chevy TH400 and im using a 1/8 thick adapter plate. The problem is I keep cracking flexplates. At first I assumed this was because I do not have a shim between the flexplate and torque converter to make up the 1/8 difference that the adpater created so the TC has the proper clearence .
After talking with a hot rod shop and jegs im being told that because the TC is sitting 1/8 further away from the crank that when the fluid pressure builds up and the TC moves forward it has an extra 1/8 inch to move and therefore flexing the flexplate so much it cracks.

now i dont know if this TC needs to sit more towards the block or further away

does this makes sence?? anyone have any thoughts or suggestions on this issue?


Last edited by gilby246; 07-09-2005 at 07:27 PM.
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Old 07-09-2005, 08:57 PM
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With the eighth inch adaptor you're convertor is sitting further out from the pump/front of the tranny. An eighth inch spacer between the crank and the flexplate would compensate. I would make sure the convertor hub fits the pilot hole in the crank. This is a pretty common cause for the problem you describe.
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Old 07-09-2005, 09:04 PM
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I ended up ordering a mid plate extention kit from jegs. Comes with a peice that sits in the pilot hole and 3 shims for the converter flexplate. I guess some adapter plates come with these already and some dont. Mine did not come with them so i didnt know any better....cost me 2 flexplates
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Old 07-12-2005, 05:13 AM
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broken flex plate

I have seen this many times over many year in the tranny business, the best and in my opinon the only fix replace tranny case with bopc case. Buick, Olds Pontiac and Cadillac. If your compare the cost and time you have already spent on not having correct case it makes sense to get the right case and fix it one time.........
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