Nowanker

S2 = Shorter final drive. Otherwise same gearing, and probably gearset as well.

333pg333

Not quite. The 5th gear ratio in the turbo is 0.8286 and in the S2 it's 0.7778. Also in the turbo the 1st and 2nd are hardened but I don't think they are in the S2.

Nowanker

Thought hardened 1st and 2nd was only in the Turbo S box?

333pg333

Hmm...maybe. Would need a more qualified opinion than mine like Kevin Gross or Jim/Oddjob.

Nowanker

Back in 'the day', the Turbo S boxes were coveted, and I think that was one of the reasons.
Interesting to note that the S2 box has a taller 5th.

Oddjob

Memory might be failing...

My offhand recollection is that the Turbo S AOR transmission had harder or additional case hardening process performed on the 1st and 2nd integral gear teeth of the input shaft. I've only ever seen it written in a qualitative way, never an actual Rc or Brinell hardness increase vs stock. So I don't know how much harder/stronger the teeth are, if it's a significant or insignificant difference. I don't recall seeing or hearing of notable failures of the 1st and 2nd gear teeth on the non AOR input shafts over the years. I've used 9U, 5R, AOR, AOS/T transmissions in track cars, and haven't broke a 1st or 2nd gear. Concern would be with launching, higher power.

And I'm pretty sure the PET part number shown for the AOS/AOT S2 transmissions is the same AOR Turbo S input shaft part number. But the question is when/if the actual Turbo S input shafts were installed in the S2 transmissions during assembly, or if old stock standard Turbo input shafts were used until supplies were exhausted. I don't know if the actual shafts can be told apart - I don't know if there are stampings/markings or coloration of the teeth that can be used to differentiate an AOR vs non AOR.

The AOR transmissions were also desirable for the included LSD and external oil cooler.

blade7

AFAIK the hardened shafts became standard spec with the 250 bhp uprate, along with the LSD and cooler loop. I think the LSD was an option on 220 bhp cars.

JET951

In Aus the 1989 cars were all specced as turbo S although not advertised as S. In 1990 Porsche Cars Australia then specced almost all the 944 turbos as base as they could get to get the price down. So they would be non M030, Non LSD, most did have the oil cooler
Regards
Sean

333pg333

Sean do you know if there is any difference between pre '89 and '89+ as far as gear hardness goes?

JET951

I use to know this, I think from memory its the tater turbo gearboxes, It should be mentioned in the new car features I will have a look a little later.

KevinGross

The 016.311.105.AL input shaft introduced with the Turbo S superseded the 016.311.105.T previously used. There is no documentation indicating if or when the supersession was used in the S2 transmissions: maybe yes, maybe no. I suspect VW used up their inventory of the .T in the S2 boxes and then flipped to the .AL. Who knows. I stock them, keep an eye on 1st and 2nd when servicing, and if I find cracking or wear, replace.

The base 944 is not immune to issues with these gears on the input shaft. With age and lack of attention to lube, I see problems.