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4l80 Rebuild: input shaft won't turn after pump install

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Old 11-12-2015, 10:58 PM
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Default 4l80 Rebuild: input shaft won't turn after pump install

Just finished assembling, and noticed that I can't turn the input shaft after I've installed the pump. When it's only the overrun clutch assembly and the input shaft spinning, it's easy to move. When I install the pump, the input shaft won't move. The output shaft spins freely in one direction, and with more effort, will spin in the other.

The pump cover is a brand new unit because my stupid *** let the drill bit walk, but it's the same pump year as the stocker (03). I did all the bushings and seals in the trans. The overdrive and forward drums are both fully seated. The few times I've pulled the pump back off to check it out, it's pulled the overrun assembly/carrier assembly with it and I have to separate them forcefully.

Is this normal? How hard should this thing be to spin?
Old 11-13-2015, 10:54 AM
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sounds like the overrun clutch hub isn't seated into the overdrive clutches all the way and the pump is binding it unless you have overtight bishings in the pump stator itself. check enplay also the and forward clutch pack clearance the input shaft locks into front planet with the sprag locked and turns the forward drum 1.1 if the forward clutches are tight and not moving freely it will add resisitance also make sure you have the bearing in place on the back of the forward drum also
Old 11-19-2015, 05:32 PM
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you might check if you have the direct clutch drum in contact with all 4 intermediate clutches
Old 08-28-2016, 11:49 PM
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Originally Posted by john kilgore
you might check if you have the direct clutch drum in contact with all 4 intermediate clutches
Additionally I have learned you can air check this to make sure it's seated by giving air to the center hole in the case. If the direct pushes up and moves when you give it air you have not engaged all clutches yet.
Old 08-31-2016, 01:31 PM
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I just had the same thing happen as Predator said. The shaft really wouldn't spin and virtually no endplay even with no washer. Im assuming it was my overrun clutches not fully seated. I fixed that and it took the biggest washer I had .122 I think to get my endplay to .017.



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