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4l80e Pump gear wear

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Old 01-01-2024 | 11:17 AM
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From: Easley, SC
Default 4l80e Pump gear wear

Hey everyone,

I just want to thank everyone that has put valuable information in this forum over the years. I’ve been reading all the information I can find and the explanations that Vortec, Maroon, cline, Jakeshoe and many others have put here is invaluable!

This is a “good” transmission I bought from a local yard and going through parts that need replaced. Just to preface, this will be behind a 900hp+ motor. As this thread indicates you can see on the gear pocket has wear on the leading edge of the crescent. Inner gear to that section of crescent is .028” which exceeds the .012” I’ve read acceptable. I can obviously catch my finger nail on the very edge of this crescent. You can see that the bushing is trashed in the area as well. All other tolerances are within the ranges outer gear to pocket is between .005 and .006”. And with a straight edge across the pump gears I cannot get a .003 feel between.

Second picture is of the damage on the inner gear to torque converter hub.

My ultimate question is would a new set of gears possibly get me within spec for what I’m doing or do I need to just get a new gm pump half with the gear set? I’m pretty sure I already know the answer I just dont want to trash it if it’s still useful.

Thanks for any insight from the well experienced!



Old 01-01-2024 | 01:04 PM
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I would replace that pump body and gears. They're not expensive. also double check your block dowel pins and the dowel pin holes on the transmission case. use a converter pump drive hub to center the halves on reassembly.

very interesting to see a junkyard core have the pocket mod to the pump body

Old 01-01-2024 | 01:13 PM
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Originally Posted by truckdoug
I would replace that pump body and gears. They're not expensive. also double check your block dowel pins and the dowel pin holes on the transmission case. use a converter pump drive hub to center the halves on reassembly.

very interesting to see a junkyard core have the pocket mod to the pump body
I did the pocket mod since this pump half was questionable and if I screwed up I wouldn’t be out too much
Old 01-01-2024 | 02:31 PM
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Me personally I would replace that pump period . and check alighnment as TruckDoug mentioned. That does not look like normal wear or even presure related but more like alighnment or a bady warpped flexplate .
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