TRNW-2: 6L80, Pump & bell housing machining

[art landeck]

Most just cut just  the pocket because they take off so little and 
usually you need the oversize washer on the stator although there is a 
done of end play there anyway. cutting the other surfaces when done 
proper restores the bell to factory specs
most cnc guys do everything the manual guys do just the pockets because 
to machine the other areas you gave to reposition the bell housing for 
the next cut

Chris Kershaw via trnw2 wrote on 9/4/2025 10:15 PM:
> TRNW E-Mail Forums *Date:* Thu Sep 4 19:15:05 PDT 2025
> *Subject:* 6L80, Pump & bell housing machining
>
> Group, we have had some recent issues with machined 6l80 bell 
> housings. I've had a few that would make pump noise under heavy 
> throttle. Seems like it would happen once or twice and clear up after 
> the initial 10-mile road test. I even pulled pans and inspected 
> filters after 40-50 miles and no debris, so we let them go.
>
> Recently pulled a comeback out for noise and found the pocket depth 
> was uneven, and the slide was tight in one area when checking 
> clearance with a straight edge. Our local guy who originally machined 
> it said the depth was off by .001 and fixed it. He machines them on a 
> lathe. He does not cut the surface that contacts the case. I've 
> noticed a lot of videos show these being cut on a milling machine.
>
> The Machined bells we have gotten from natpro or transtar appear to be 
> cut with a milling machine and have a much smoother surface than lathe 
> cut. They are also cut at the surface that contacts the case.
>
> Is there a machinist (I'm not one) reason to cut the bellhousings one 
> way or the other or with one tool or the other? is it just personal 
> preference? Any opinions or experiences on this would be appreciated.
>
> Chris Kershaw
> Kershaw Services Llc The Gear Box
> Mechanicsville, Maryland USA
> TRNW Member Since: 5/1/2023
>
>
>
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