stupid transaxle question

Started by poohbah, January 14, 2020, 02:13:14 PM

Previous topic - Next topic

poohbah

This might sound dumb but I'm wondering about the 2nd gear crunch on my GTV.

I had the gearbox out to replace a busted planetary gear in the diff about 3 years ago, and had 2nd gear synchro replaced then, which eliminated the crunch and made the gear change really stiff for a couple of months until things loosened up over time.

However, for quite a while now, it's been crunching again intermittently on changing into 2nd (mostly only downchange) if I'm too impatient on the shift or if the box is not warmed up.

The question I have is that it actually sounds and feels as though it's coming from the base of the gear stick, rather than from down back at the gearbox itself.

Is it just transferrred noise/vibration from the synchro, or could it actually just be something at the front end linkage/selector?

it's not terrible, and pretty easily managed through careful gear-changing, but I am curious.
Now:    2002 156 GTA
            1981 GTV
Before: 1999 156 V6 Q-auto
            2001 156 V6 (sadly cremated)

poohbah

Cheers Glen, I hope its not a donut - I had them all replaced about 5 years ago!

It just seems a bit weird to me that it feels like its coming from a long way forward of the gearbox.
Now:    2002 156 GTA
            1981 GTV
Before: 1999 156 V6 Q-auto
            2001 156 V6 (sadly cremated)

Garibaldi

I replaced the synchros on my 1979 Alfetta GTV 3 years ago and never had a problem. Mind you I did buy the expensive Goetze rings. Even with these you still had to shift gears slowly until the transaxle warmed up.

poohbah

#3
The diminishing numbers are scary, as are the replacement panel/parts prices.

I saw an ad on FB yesterday offering an early GTV shell (that was largely rusted out forward of the A pillar) for $6k.

Mind you I did look longingly at the straight/solid rear valance ...

*correction - it's an '82 GTV and actually more of a  donor car than just a shell (rear hatch and bonnet already sold). Aside from aforementioned rust in front looks pretty solid.

But certainly gives me hope for the rising value of my licensed & running but *requires work '81!
Now:    2002 156 GTA
            1981 GTV
Before: 1999 156 V6 Q-auto
            2001 156 V6 (sadly cremated)

poohbah

I've got no intention of selling mine either, but would be nice to be able to tell the missus that the ledger might get back into balance eventually! ;D
Now:    2002 156 GTA
            1981 GTV
Before: 1999 156 V6 Q-auto
            2001 156 V6 (sadly cremated)

bonno

Hi Poohbah
In addition to the comments above, it might be worth considering to check for worn gear lever connections and link rods (worn bushings/pins).

poohbah

cheers bonno. That's exactly where the sound/vibration seems to come from. Will have to have a poke around.

Now:    2002 156 GTA
            1981 GTV
Before: 1999 156 V6 Q-auto
            2001 156 V6 (sadly cremated)

martym00se72

If you don't already, you could learn to double de-clutch. I taught myself as a result of 2nd gear...
'83 GTV6 - 3.0 is in! Ohhh yeah!
'99 156 T-spark - Formula 98 ready!

What do people do with their old 2.5...?

Domenic


Everyone is aware that the Goetze rings that are currently on the market from overseas vendors are not made by Goetze (Federal Mogul).

Goetze sold off the machines and tooling to produce the synchro rings back around 2004-2005. they even stopped making gasket sets. All they produce now are piston rings and cylinder liners.

So whoever is making them now is just stamping them with GOE and they are technically re-production/copies of the originals.

If you want original synchro rings, they are out there you just need to find them, sometimes they can be had for cheaper than the new production items that can be purchase online.

Domenic

Hi Sportiva,

I always keep an eye out for them, it does take time and patience to locate them, but so far in the last 6 months I've found 4 original Alfa ones and 6 Goezte synchros (production stamp 1998) in Italy. That is all the suppliers had left

Again, it just takes time and patience to locate them


NSharpley

Doesnt look like anyone has mentioned this but if you think the sound is coming from under the stick and is only in 2nd gear, it could be possible that the linkage underneath is making contact with the propshaft.   

It would only do so in 2nd gear.

If you have a slack centre mount carrier bearing then the propshaft may be moving sideways enough to contact when you push the stick left and back for 2nd (this of course translates to right and forward underneath the car which puts it at its closest to the propshaft).

Rule it out by raising the car, starting it and get under there and visually inspect the shaft whilst running and the engaging of 2nd.

I think its unlikely this is the case ... but it is possible.

Current Alfa:
1975 Alfetta GT 2.0 Race car
1979 Alfetta GTV (Resto)
1972 105 2000 GTV (Resto)
1987 Alfa 75 2.5

Past Alfas:
1982 Alfetta Sportiva (briefly in my possession. Restored and sold)
1989 Alfa 75 2.5
1982 Alfetta Sedan 2.0
1976 Alfetta GT

minipete

I used to think the Italians made my Giulietta crunch in second on purpose because old Ferraris did the same.

When I rebuilt the gearbox I was interested to see first and second (which are large gears) use the same size synchro as the upper gears.

The synchro has to arrest to rotation of the gear for clean shifts and the larger gears would make the synchros work much harder.

I decided the answer was to pause in neutral before pulling into second (which gives the synchro time to slow the gears) and haven't had a problem since.

NSharpley

Quote from: minipete on February 08, 2020, 12:42:01 PM
I used to think the Italians made my Giulietta crunch in second on purpose because old Ferraris did the same.

When I rebuilt the gearbox I was interested to see first and second (which are large gears) use the same size synchro as the upper gears.

The synchro has to arrest to rotation of the gear for clean shifts and the larger gears would make the synchros work much harder.

I decided the answer was to pause in neutral before pulling into second (which gives the synchro time to slow the gears) and haven't had a problem since.

Double clutching does the same thing and doesn't require any pause. 
Current Alfa:
1975 Alfetta GT 2.0 Race car
1979 Alfetta GTV (Resto)
1972 105 2000 GTV (Resto)
1987 Alfa 75 2.5

Past Alfas:
1982 Alfetta Sportiva (briefly in my possession. Restored and sold)
1989 Alfa 75 2.5
1982 Alfetta Sedan 2.0
1976 Alfetta GT

Colin Edwards

Could it be transaxle / GL5 oil NOT containing friction modifiers works better? 
The higher friction provided by some oils NOT containing these additives allows the synchro and respective gear to "synch" more readily?
Present
2023 Tonale Veloce
2018 Abarth 124 Spider
1987 75 3.0

Past
2020 Giulietta Veloce
2015 Giulietta QV
2009 159 3.2 Ti Q4
2012 Giulietta TCT Veloce
2006 147 Ti 2 door Selespeed
1979 Alfasud Ti 1.5

ALF750

Not an Alfa this time but useful?:   The Getrag gearbox in my '94 Ghibli II is quite heavy to use and slow until the oil warms up, much like the Alfetta.   I spoke at length with a BMW mechanic (lots of them use use Getrag also) and he said to use basic mineral ATF in the gearbox.   I have and it is so much better.   The reasoning is that the greater friction/less lubrication from the ATF helps the cone match the synchro speed to the gear (?)  I don't know how well suited ATF is for teh transaxle differential though....