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LS 4L80E combo crossmember flex need help

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Old May 27, 2019 | 12:21 PM
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Default LS 4L80E combo crossmember flex need help



I need some guidance. I have an LS 4l80e combo in a 71 chevelle with a G force crossmember. I have added load spreaders on the frame mounts and still can move the crossmember 1/2" up and down in the middle. This is the crossmember and transmission moving together. Everything is new and torqued. Thoughts?
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Old May 28, 2019 | 07:14 AM
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thoughts on what?
Yep...i think its a crossmember
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Old May 29, 2019 | 03:22 PM
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Well that was certainly helpful.

I am wondering if the flex that I am seeing is normal or if I need to address it somehow. Everything is heavy duty and torqued tight.
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Old May 29, 2019 | 04:03 PM
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Where is it flexing? Is the crossmember itself flexing or is it flexing at the chassis?

1/2" of true flex seems excessive.
what do you have for engine mounts and what does g force say?
I would reach out to them since they built the thing
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Old May 29, 2019 | 06:58 PM
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Poly mounts all around. G Force seems to think it's fine. Boeing thought that the 737 MAX was fine too.
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Old May 30, 2019 | 07:09 AM
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Sorry to tell you...but you aren't dealing with a boeing 737 MAX

and the 737 max had its flaws but it was a mixture of telemetry sensors and bad coding that lead to crashing...not the chassis flex itself. but it certainly didn't help

AAAAAAnnnnnnyy who...back on topic. Where is it flexing from? the ends where it bolts on, the center where the "hump" is welded into the crossbar, etc
A welder and diagnosis of flex would shore it up in a jiffy
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Old May 30, 2019 | 11:15 AM
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Post some photos from multiple angles of the cross-member in a position, that the flex or sag can be viewed and I'll tell you if and how it should be reinforced and welded.
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