Loud transmission noise in gears 1-3

[mflande]

I just got my 82 Fiat Spider up and running and was out today driving in town when I started to notice a clicking sound coming from the transmission in 2nd and 3rd gears. Nothing really noticeable until I stopped for a few mintues and when I got back on the road the slight clicking had turned into a full on machine gun sound. It is also happening in 1st, 2nd and 3rd gear but not 4th. Its so loud that it was echoing off buildings as I drove by. The loud clacking noise seems to be in time with the engine acceleration and stops when I disengage the clutch.

Ideas on what could be causing this?

[vandor]

> stops when I disengage the clutch

With the car rolling, or stopped?

Sounds line one of the layshaft bearings is going, or the nut at the back of the layshaft has backed off.

[mflande]

The noise stops both in motion and when standing still, once the clutch is disengaged.

[vandor]

Unfortunately the transmission has to come out to find the culprit. You could drop the pan and see if you can see anything obvious, but it's unlikely.
When you are rolling with the clutch disengaged only the upper rear and upper middle bearings are turning - so we know those are ok. It could be any of the other bearings, or the nut on the lower shaft. Mind you the nut coming off usually just makes a scraping metallic noise.

[mflande]

Gotcha. Thanks for the info. Sounds like another adventure in Fiat repair is on the horizon...

[mflande]

So, pulled the transmission out and no issues with the layshaft bearing or nut. Cracked open the transmission housing and immediately found the largest gear of the layshaft was missing two teeth. Will try to post picture.

https://www.facebook.com/matthew.flande ... uploaded=1

Had some difficulty getting the front layshaft bearing to come out of the transmission housing and was curious if it needed to be replaced as well as the layshaft.

What would cause breakage of teeth on the layshaft and is there something I need to do besides replacing to prevent it from happening again?

Thanks again for your input.

[vandor]

This is a very uncommon failure. I've seen all those teeth shear in a transmission that was run with no oil.
Did a normal amount of oil drain out of the transmission? Also check the front layshaft bearing for play.

[mflande]

I think uncommon may be the name of the game with this vehicle.

There was plenty of oil that came out of the transmission. Would you recommend replacing that bearing just to be on the safe side?