Gearboc whine and differences between 365GTC4 and 365GT4 2+2 gearboxes

Interesting as I have not heard that. The 400/400i/412 manual gearboxes are basically the same as the C4 but I have not heard or experienced any whine in my own 5 speed or in the other half dozen 5 speeds that I have driven.

 

+1

 

I had noise at that speed in the 330. After much hunting, it turned out to be a driveshaft balance issue.

Regards,

Art S.

 

but they are 'there' though...they're not quiet and you can definitely hear them.
the C4 and the GT4 have the same box, as far as i know...
but the 400 and beyond use the 308 type syncros...
and they're still kinda loud, but you are practically sitting on top of it.

interesting...

Art, i'm sorry you haven't heard from me...i've meant to call you a hundred times.
i'll try you this afternoon and, again, my apologies.

brettski

 

My C4 does not have a gearbox whine. Have yours ever been rebuilt? my Datona developed a whine after a transaxle rebuild.

 

My C4, which was an early car (14993 as I recall) did not whine....I do believe there are differences in the C/4 gearboxs late to early production.

Regarding the statement that 400 / 400i boxes are "basically the same" that is incorrect. Ken McKay, who was the chief technical guru for FNA in the 1980's (and he knew his stuff) told me later 400i boxes were different, including a "different casing material in an attempt to reduce noise". I had a 400i series II gearbox apart once and it was in fact different from what was illustrated in my 400 carb parts book.

Regardless, I've never driven a 365 or 400 that I thought had a particulary "sweet" gearbox.

 

normally, my first guess would have been the input shaft bearing as the source...
but since it's all three cars, it would seem to be something inherent in the box... gearcut ?
but if other guys with C4's and rebuilt box's don't have a whine, then i'd say differential.
but, again, being in all three, it would really imply design, as you've suggested.

is it possible you only hear it in 5th because the motor is quieter at the lower rpm's ?

or is it possibly the hanger bearing in the driveshaft ? but that's more of a hum or howl...

this is a tough one to try and call...but i'd sure like to know what you end up finding...

 

definitely interesting...and not to speak for him, but i think he probably meant the guts.
we've had 365 GT4, 400 and early 400i tranny's completely apart recently...
but not a series 2 400i...and thinking about it i'd have to agree that they seem quieter.
i just figured the tunnel was better insulated.

and ya, i think i know what you mean about the "sweet" part...it's definitely a man's tranny.

 

Brett:

My mind is no doubt playing tricks on me (my conversation with McKay was probably 20 years ago), but I seem to recall that amoung other things he said the late 400i boxes had a case that was cast iron, though I cannot imagine Ferrari using cast iron for a trans case!

As I say, it was at least 20 years ago....

Cheers!

 

Several years ago I was checking out the drive train of a 412 5-speed that was getting an engine overhaul. The entire drive train was out of the car so I got a good look at it all. I noticed a reddish tinge to the aluminum paint on the transmission case, and on the differential case as well. Upon close examination I realized they were both cast iron. This puzzled me as the cases on my C/4 are most definitely aluminum painted cast aluminum, just like the engine castings. I had assumed the changeover was to increase strength, and had never considered gear whine suppression as the motivation, but now it makes sense. My only remaining question was just when this was instituted? For me it's been mostly a trivia question (as my C/4 cases are aluminum as I would prefer for lighter weight), but now I am more interested in knowing when this was done. Was it between C/4 and GT4, 365 and 400, 400 and 400i, or 400i and 412?

Les

 

After 1981.
My 1981 400I has a aluminum gearbox and diff.

 

Yes I have a "whine" that is faint but there.

 

The series II 400i I had apart definitely had an aluminum case...

 

Brett can confirm for me but I'm sure the gear box on my 75 365 GT4 2+2.

 

Hmmm... Could it be the type of diff or gearbox oil?




"though I cannot imagine Ferrari using cast iron for a trans case!"

Ferrari used cast iron for there engine blocks on the F1 cars at one point in the 90's- very thin wall castings 1.5mm in some areas.

Cheers,
Paul

 

All the 365GT4 2+2 & 400GT gearboxes I've seen are cast iron and weigh an absolute ton.

I didn't realise the C4 box was different (alloy) or I would have used one in my special to save weight. The 400i aluminium too, I'm amazed....

By the way Ferrari started using cast iron cases right back from the 250GT SWB steel body versions in 1960 if not before.

3 boxes with the same whine sounds to me like it could be something outside the box.

 

The whine could be caused by the ring and pinion gear setting. I had a whine on my Daytona. When we overhauled the transmission we put in a new ring and pinion and the preload tolerance was set very precisely; no more whine.

 

and you'd be right Jim, it is cast iron.