GTV - clunk when moving off

[poohbah]

Folks,

Looking for some diagnostic advice. My 81 GTV has started making a nasty clunk after changing into 2nd (occasionally in 3rd) as I start to move off. The sound and vibration feels to be coming from general area between engine and gear selector - it sort of feels like it is trying to jump out of gear. It doesn't happen every time, but is intermittent.

I had the propshaft out, donuts and main centre bearing replaced about 3 months ago, and apart from usual 2nd gear synchro crunch if I'm not paying attention, gears have been fine, if less than slick changing.

Any suggestions - I'm wondering if maybe the gear change connection to link rod might be loose? Or could it be clutch related? (though it hasn't felt at all like clutch is slipping).

[Mick A]

Gday,

I think it will be a gearbox mount. Probably the passengers side one.

Mick.

[poohbah]

Cheers Mick, will investigate further.

[poohbah]

Hmm, did it in 1st this morning. Definitely coming from the front of the car, not rear/transmission.

[GTVeloce]

I agree with Mick. Same thing happened to me and he suggested gearbox mount. I had replaced the centre bearing in my prop shaft a few weeks earlier and musn't have torqued the gearbox mount nuts properly.

If it is at the front you need only check the three engine mounts (the rear may have collapsed causing the engine to lift and fall under load).

[poohbah]

Cheers GTV (and Mick). Sounds like that could be the culprit.

[Mick A]

Yes sorry I misread your initial post I thought you had written between the gear lever and the gearbox, but you meant up front. My apologies. Yes could be a failing engine mount or just the exhaust knocking on the floorpan under torque.

Once again another problem that is hard to diagnose without seeing the car, can only give suggestions!

Cheers

Mick

[Mick A]

Hey Poohbah we have the same amount of posts. How cool is that!

[poohbah]

Haha cool indeed, except that you generally seem to know what you are talking about, whereas I'm mostly flailing about in the dark of mechanical ignorance ...

[poohbah]

Well, the problem has now been identified and is being fixed.

Worse than initially thought unfortunately.

Planetary gear bearing in the gearbox seized and broke, stripping quite a few splines off the planetary gear.

So the bad news is that the gearbox had to be dismantled to have the planetary gear replaced.

The good news is that there is no sense putting it back in without also tidying up the rest of the box, including new synchro rings etc which are showing the signs of 34 years worth of wear and tear. So it ought to feel like new.

[V AR 164]

Yikes, You don't seem to be having much luck with Alfa's lately I gather.

Hope it all goes well!

Andrew.

[poohbah]

She is truly like painting the harbor bridge - start at one end and keep going...

Hopefully, after this I'll get a few months of relatively trouble free motoring!

[bteoh]

Maybe time to source a 75 Twin Spark gear box with LSD? I recall Martyn having one for sale recently? (See WA section post)

[poohbah]

Cheers, but too late anyway. Should pick up car from the workshop today or tomorrow.

[poohbah]

Well I now effectively have a new gearbox and diff ... and a much lighter wallet.

New planetary gear, new 1st, 2nd and 3rd gears, 2 new synchro rings and clutch bearing. Also replaced exhaust manifolds, after cracks were revealed in the old ones during the work.