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Discussion Starter · #21 ·
Could the transmission have been rebuilt incorrectly? This input shaft may be sticking out too far. Is that a possibility?
 

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You can look at the input shaft as it goes through the pump, the clutch packs and resides on the planetary. If any of these parts are missing or out of order, they can certainly have an affect on overall input shaft protrusion of the pump at the bell housing. Not a typical issue but it's happened I'm sure... Did you purchase this trans new or did you have it rebuilt locally?

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Discussion Starter · #23 ·
Original th350 to the car. Just rebuilt by a reputable guy. Converter guy says he been using the Sonnax billet covers for decade and never seen this issue. He claims my input shaft is sticking out too far. Not sure who to start with. Converter guy or tranny guy.
 

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As mentioned up above, is the tail end of your crankshaft completely empty? is it freshly sanded and free of any bushings or bearings? doe the converter bolt up without an issue? I think you mentioned that it does but just covering all bases before we move on with the troubleshooting.
 

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Discussion Starter · #27 ·
Cranshaft is a brand new Scat unit. Fresh built 383 stroker. Converter bolts up like butter. Nothing in the way. I have a nice SFI approved 168 tooth flexplate and the converter presses on it. I switched it back to the original 153 flex plate that was on the old 307 I took out and there is zero play but no pressure. I can spin the converter. It barely makes contact but no play at all.
 

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Cranshaft is a brand new Scat unit. Fresh built 383 stroker. Converter bolts up like butter. Nothing in the way. I have a nice SFI approved 168 tooth flexplate and the converter presses on it. I switched it back to the original 153 flex plate that was on the old 307 I took out and there is zero play but no pressure. I can spin the converter. It barely makes contact but no play at all.
so same issue regardless of the flexplate you use, right? I'm leaning on the issue being the converter but there may be an issue with the scat crank... do you have pics of each of the flexplates installed and the tailshaft of the crank and bearing location in the tail? where the converter hub sits...
 

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Discussion Starter · #35 ·
My gut tells me the converter billet cover is too think. Converter guy says he never had an issue and input shaft sticking out 1/4 inch too far
 

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looks like the shaft maybe protrudes too far out of the pump, about 1/16" to 1/8".. tough to tell but a stock converter could be that worn without issue on a rebuilt trans and still run fine not under serious loads... Still hard to tell but when was the trans rebuilt? I'm assuming you ran this trans behind the motor before it was built and it had the stock converter in it without issues...
 

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My gut tells me the converter billet cover is too think. Converter guy says he never had an issue and input shaft sticking out 1/4 inch too far
I'm still leaning towards the converter being the culprit on this issue. Other things may not be exact but... 1/8" to 3/16" is a large variance to make up... You shouldn't need to add anything to make the converter work with your trans. that's asinine....
 

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Discussion Starter · #38 ·
Ran great stock with stock converter. Just got it back from rebuild friday. Stock converter fits just right.

aftermarket unit bottoms out on the input shaft with zero clearance to the flexplate AND…. Only engages the pump about 1/8th
 

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Ran great stock with stock converter. Just got it back from rebuild friday. Stock converter fits just right.

aftermarket unit bottoms out on the input shaft with zero clearance to the flexplate AND…. Only engages the pump about 1/8th
New converter then. Can't imagine anything else it could be but that if everything else worked fine. Send it the f back and ask him to perform a forensic teardown or fitting
 
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