Grinding noise when accelerating hard!?!?

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Feb 27, 2010 | 10:02 PM

chevrev

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Grinding noise when accelerating hard!?!?

Just got my LS1/4l60e into my 57. Runs great, smooth, powerful ,etc...BUT, when I really get on it and accelerate hard, there is an aweful grinding noise. It sounds like its under my feet (tranny area). My first suspicion would be the transmission. It was a fresh rebuild, but maybe not a good one??
Otherwise, it seems to shift fine and run out well, but that grinding noise has me worried!

Any ideas????

Feb 28, 2010 | 07:07 AM

55chevy

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I would look around the driveshaft and other areas to see if you have any clearance issues when the engine is under torque. Also, if you can see the flexplate, look for rubbing or loose bolts on it that could be rubbing.

Feb 28, 2010 | 07:25 AM

BadVRod

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Might check your rear end. Mine made a nice grinding noise right before it locked up.

Feb 28, 2010 | 07:38 AM

55chevy

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Quote:

Originally Posted by BadVRod

Might check your rear end. Mine made a nice grinding noise right before it locked up.

I was just thinking about the rearend and driveshaft length when I read this other post.. https://ls1tech.com/forums/conversio...sion-case.html .

Feb 28, 2010 | 07:53 AM

Jimbo1367

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noise

Quote:

Originally Posted by 55chevy

good idea.

Feb 28, 2010 | 11:15 AM

chevrev

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I jacked the rear end up and noticed that the floor pan tunnel just above the universal joint where the drive shaft meets the c4 differential has some gouging/scraping in it. The drive shaft/rear end joint must be flexing enough to touch it when put under a heavier load (ie, hard acceleration) to touch it. Hopefully this is the problem and the tranny is fine! We'll see...I'll make some adjustments/modifications so the universal joint can't make contact with the undercarriage and see if that solves it.

Feb 28, 2010 | 11:31 AM

gofastwclass

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From: KCMO

Sounds like the car must be lowered. I've had that problem when the pinion angle was screwy or the car was lowered too much for the available transmission tunnel clearance.