ALFAGTV6.COM

[Mats]

It's not the power that breaks gearboxes, it's the torque. That and bad oil.

(Theoretically power can break boxes due to overheating of the oil but that is really a cooling issue, not power)

[gtv-racer]

i'm aware of that. Oke, is it then 400 rwh Nm or at the crank.

[Mats]

Hopefully more then 400Nm at the wheels...

(Ok, I'll shut up now)

[gtv-racer]

yeah , shut up

[MR2 Zig]

hehehehehe!

[kevin]

GTV -racer , all the failures here are pinion. Its not the guys assembling them either as all the boxes have been overseen by ex autodelta race guys who have immigrated here. All the boxes have been from either a gtv6 or a 75t.even my boxes I trippled checked every thing with the Alfa factory gearbox assembly manual.
Talking to the guys who raced the gtv 3.0l in the eighties, they never had any pinion failures but they did run straight cut autodelta boxes.
QUESTION - is the 75 3.0 pinion bigger than the gtv 6 as I have never seen one these cars or a gearbox from one. (did not get 75's here). Could ''play ''in CV joint transfer shock or is that stupid question .

[MD]

Kerb hopping could contribute I would think.

[MR2 Zig]

I didn't think they had 'roos in sarf efrika.

[MD]

Are you kidding me ?? !!
Just ask Kevin, they're ALL DANGAROOS over there man !!

[gtv-racer]

Kevin. Saw the picture of a 75 v6 and the pinion looks the same size. Then you get als the stuf greg talked about.

But anyone know approx. max toque at the wheels?

[kevin]

MR2ZIG, your suggestion of annealing is spot on with the suggestions I had from two gearbox manufactures here. These guys make a lot of race boxes and there comments from my lab reports on the strenght of the entire pinion tooth is too high for race but perfect for durable road cars. They mentioned I need to send an old housing in to minimise warping when annealing.
Will keep you posted . A comment was made that the pinion design is good for 500hp thus its a matter of correct surface treatment for 'shock' under racing (kerbs, fast chainge downs-ups ).

[la_strega_nera]

Random thought - GT40s (from memory) had Guibos instead of inner CV joints - presumably to help reduce shock loadings on the ZF - potentially would help the alfetta transaxle?

Kevin - they're annealing and then re-hardening the gearset? I assume they've ground somewhere to get through the case hardening to get a representative core hardness? any idea what core hardness they're aiming for?

[Mats]

Random thought - GT40s (from memory) had Guibos instead of inner CV joints - presumably to help reduce shock loadings on the ZF - potentially would help the alfetta transaxle?

Must have been the pride of British Engineering somehow involved on that one..?
Sounds like the Mini and the Lotus Elan.

[la_strega_nera]

Just realised they also had uni-joints at the wheel end.
Probably the handi-work of Broadley still - they certainly had problems with teeth coming off the Colotti boxes in the early cars.

[slyalfa]

Well the 3L USA box has a bigger pinion and smaller ring do the the change in final drive as far as I know. how else could you change the final ratio.
So a tall box might be stronger but then have bad gearing.
also the diff is a 4 way. The old boxes it was a 2 way don't renumber when they switched. but I think it was with the V6