365GTB/4 (Daytona) Ring Gear Backlash?

Are you sure about this 0.04mm as the range (from 0.03mm to 0.04mm) seems awfully narrow or should I say almost non-existent at 0.01mm (=0.0004") ?

It's been awhile since did one & don't have my notes handy, but will try to check them later this week.

 

What backlash clearance other, same era transaxles (i.e. 275GTB/4, 330/365GTC, etc) call for ?

 

Here’s the data from the 330GTC workshop manual:

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Brian, I agree the backlash clearance numbers seem (too ?) tight and as I mentioned (right or wrong) the range also seems a bit narrow, but it wouldn’t be first time I found factory manuals/literature related to 365GTB/4s having (unintended ?) data/information inaccuracies.

Also, while I’ve never received any formal education in English (or in mechanical/technical engineering or related skills training) I’ve found Mr. A. Wallace’s translation of the factory WSM for 365GTB/4 somewhat lacking on technical accuracy & clarity.

Kevin, the page you posted appear to refer to clearance/tolerance spec’s on the transmission side of the (330GTC ?) transaxle.
If you can find & post backlash spec’s for the differential ring & pinion, it might prove helpful for comparison.

 

TTR…yep, wrong specs…sorry. And yes, for 330GTC as noted above the photo.

Here are the pinion/ring gear specs from the 330GTC workshop manual for direct comparison:

“In the correct operating position, the backlash clearance between the pinion and ring gear must not exceed 0.02 to 0.03mm, and at the point where the teeth are closest, there should be no forced effort noted.”

So, even tighter than the Daytona specs.

 

Brian, do you by chance have an access to someone with OEM WSM and technical level fluency in Italian language ?
I have a feeling something might’ve gotten lost or misinterpreted in translation.

 

Timo, I have neither OEM WSM, but speak Italian fluently, and I can read tech. stuff as in all the AR we've done in the diff or the transmission. Dino, alike.

Can try to help, just post and I will try.

Regards,
Alberto

 

Thanks for the offer, Alberto, but I'm not the one in a need of this information (at least for now) nor do I have a WSM for Daytona in Italian.
I just suggested the idea to Brian.

If they're still needed I'll try to look up my notes on this over the weekend.

 

Brian, I’m sorry I haven’t had a chance to look harder yet, but will a.s.a.p.
I’ve been swamped with couple of pressing (non-Ferrari) projects, including one which was finally picked up by a transporter late Saturday afternoon and is headed to an event Indiana in couple of weeks.
I also need to wrap up another one waiting to get transported to Tennessee a.s.a.p. and I’m hoping to get it finished later this week.

I assume you checked with Mr. Ottis also.

 

PM sent.

 

Brian, a parallel story for you. I have done a lot of TR and BB transaxles. Ferrari has rather narrow specs (+ - ) for them also. A number of years ago I was doing carrier preload on one and it was a hair tight in my opinion but it was a little cold in the shop. Bad part was pattern was perfect. It was lunch time so I pointed a heat lamp at it and went to lunch. I came back and that giant casting was warm to the touch, not hot but warm. Nowhere near running temp. Now the preload was just flat out too loose. None was a better description. In over 40 years I have done a lot of ring and pinion set ups and have always been very observant of how untouched diffs are done at the factory and for all makes, not just Ferrari. Factories are pretty sloppy. Quite often far from picture book perfect. I just use common sense guided by experience and its been working pretty good. As far as these big alloy Ferrari transaxles go, they expand a lot. On the tight side does not sound like a terrible idea. I have done a few 330/365 transaxles like that one and do not recall doing anything special and have never had to take one back out. One was a 275GTBC long nose and it survived a lot of abuse. Do a 300SL diff some time. No 2 teeth pattern the same. A blind guy with a hand grinder and a file cut those ring gears. In 50s Germany precision had a different meaning.