2nd gear in a new 348...

My 348 only had 13,000 km on it and 2nd gear shifts from cold were not fun, I would often skip 2nd gear and just go to 3rd. When the car was warmed up then all was fine.

 

Same here,always went from 1st to 3rd until warmed up...2nd would not go in smoothly at all.

 

You might try to find an old R&T road test article on the 348. For the 328, which they tested in May 1986, the authors commented that second gear was unattainable until the car had warmed up on a moderately cool California morning.

Assuming the five speed in the 348 is basically the same design, I'd say it's likely they were like that when new.

 

I actually pull away in second quite often which is quite easy

But your right if they were like this brand new thats crazy to sell a car like that at any price.
I mean when they were putting the cars together at the factory was this the best they could do with a gearbox?

 

Here's my theory on second gear...

The second gear cogs are the outermost on the layshaft. This means there is the maximum lever on the change mechanism (middle rod) and its synchro is in common with third gear. The shifter fork pushes on the synchro to get it into second, and pulls on the synchro to move it into third. The outer cogs are on the outside of the main compartment in the gearbox which houses 1st, reverse and the differential.

The Synchronizer sleeve is a ring. Its construction and thickness means that it is prone to more thermal expansion an contraction than the remainder of the components it interacts with. On a cold engine, the ring will have contracted to its smallest circumference (we're talking of minute amounts here...) which would have made it a "tighter" fit to the synchro components. I believe that this coupled with its fork being in the outermost position on the middle rod, all conspires to the longest lever in the whole gearbox, thus the effect in the reverse direction is to be the hardest action.

As the gearbox warms up the ring expands (again a tiny amount) and the mechanism loosens up. I think the much less viscous shockproof ultralight also sports a much thinner film (remember it is thickened to behave as a 75W90 with spherical shaped polymers). At colder temperatures thinner oils flow better, while thicker ones are stickier (the latter thus requiring even more engagement force). This may be why the ultralight shockproof oil will minimize oil resistance on a tight sleeve. I seem to recall reading that the base stock in the shockproof has the same viscosity when cold as the standard 75W90 does when warm.

Also faster flowing oils aid in heat dissipation (in reverse, they will aid in warming up the gearbox uniformly and quicker than thicker oils). The gearbox is heated passively, by thermal transfer from the engine block and the exhaust.

Every gear has a different resistance to engagement and disengagement. 5th and 4th, 1st and reverse, then 3rd and second in order of difficulty. This is consistent with 5 and 4th being actuated by the shortest control rod (the bottom one and the fork immediately by the actuator fingers), then 1st/2nd by the upper control rod and about 3-4 inches away from the actuator, and the 2nd/3rd gear the furthest away (at exactly the opposite side of the actuator fingers). In terms of forces, for a constant friction in the fork/collar, the further away from the actuator fingers the fork is, the larger the lever arm needed (then a pushing motion will require more force than a pulling one). I wonder if it is a pure coincidence or the reason for this behavior.

I moved the forks in my spare gearbox, and when actioned AT the fork, the forces are largely the same. When actioned by moving the engagement fingers, 2nd is the hardest... If I add a bit of 75W90 in the mechanism, not much difference. If I add WD-40 (after degreasing with acetone) it is a bit easier. If I warm the 2nd gear ring slightly (with a hairdrier), then spray WD-40 on it, then it is a hot knife in butter. Warm and dry is also easier than cold with 75W90. From the actuator finger it is always much more difficult than at the fork.

My 2 cents worth and wondering if it is a good reasoning or mere conjecture...

Marco

 

gg

 

Redline 75W90NS - 80% and 75W90 20%. This avoids chattering problems etc. It is my "car weekend". I negotiated (yeah really... I was assigned or allowed) 1 weekend every 5 where I can work on the car. So I do a lot of thinking and reading while on business journeys (just as well I think I am unconsciously competent at my work) and then unleash hell in my garage every 6th weekend... This was one of them.

In 6 weeks I will swap out the gearbox to the new refurbed one and I am largely done on the car.

I have put thermocouples in the cats ( made 200 cel metallic core hyperflow replicas for GBP 200 on each side) and have reverse engineered the exhaust ECUs. I believe I can build them for around 30-40 GBP per side in a small solid state circuit. The messy prototypes worked well, but are not installable (they are a wiring mess in a matchbox on each side).

Just having fun figuring out which hormones make the horse prance...

Marco...

 

I use Redline MTL which is a GL-4 spec oil based on Brian Crall's write up and recommendation.

Here is what he wrote (and it has been quoted on this site about 10 times):

Originally Posted by Rifledriver
My shop is right down the road from Redline and we use their products in the race cars. I have had many long conversations with them about their products and their recomendations.
Ferrari specs GL5 gear oils for the transmissions. Due to Ferraris specs Redline will not officially suggest anything other than GL5 gear oils.
GL5 basically means an oil that is designed for medium to high offset hypoid differentials. MTL is a GL4 lubricant which means it is designed for medium to low offset hypoid gears. In the 308, 328, 348, 355 transaxles there are NO hypoid gears of any type, hi, low, or medium, offset.
I am not ordinarily an experimenter with others cars except in circumstances where the official way is obviously not working but I have seen MTL used with great success and zero problems in 308 transmissions since the product was introduced many years ago. It was also the oil of choice in the transaxles of the 355 and 348 Challenge race cars with zero problems. Those transmissions were subjected to greater stresses and heat in one weekend than most of our transmissions are in a lifetime. I cannot say that however of the AGIP oil spec'd by Ferrari at the time. One session at the track finished off several transaxles and we were told unofficially by Ferrari to quit using it in cars that would see track service. That garbage did remain the official oil.
I have been using MTL in customer cars that had cronic shifting complaints for several years including one 85 308 in daily service with over 115,000 miles on it and the owner is pleased to this day how his transmission performs.
It's great oil. If you have a shifting problem use it.
I would not use it in any transaxle in a 275, 330, 365, BB, BBi, TR, 288, F40, 550, 456, 360, 430, 612, or 599. Those are all medium offset hypoid gear differentials and should have GL5 oil.

So my 2nd gear cold shifting went from not a real possibility to being fairly easy. It was a noticeable difference for me.
BT