Tranny making grinding noise.

First off......this isn't for my boat. It's a friend that has a 92 with the GT 40 and a 1:23 tranny.

He just started it today and put it in gear on the fake lake. He said it made a "gear grinding noise".

Any ideas what this could be? I'm going to his house tomorrow to try to help him determine if its normal. All I have to compare it to is the sound of mine.

Whatever you guys can come up with to help find if there is a problem would be much appreciated.

Chris.

That was my first thought.


I don't recall reading any threads here about grinding noise coming from the transmission.

So the noise sounds like its coming from the transmission.

To describe it, it sounds like the teeth of a gear that aren't finding center. It slows with power reduction and quickens with more power.

There is slop in the props connection with the shaft. I can rock the prop back and forth and j can hear it ticking against the key. I don't think that's where the noise is originating but would it be possible for vibration/noise to get transferred to the tranny from the prop?

When I rotate the shaft I can feel a tiny bit of play between it and the tranny. I can't tell where it's coming from (engine connection, internal, or shaft).

It will be out at the lake tomorrow to check further....... Any ideas come to mind?

Inspect the trans/shaft coupling closely. Maybe the shaft coupling is working loose.

Also could be damper plate going out.

Get a big screwdriver, hold it against the bell hsg & your ear to diagnose. same for tranny.

From the prop end

I think your right. We got it in the water yesterday and you couldn't notice anything.

I had never put mine in gear out of water so I didn't know they sounded like that.

"A bunch of marbles in a tin can" sounds pretty accurate.

Chris

1992 GT40?

A low rpm idle will commonly make the marbles in a jar noise. I think you need to tighten the shaft nut irregardlessly.