[Shad Laws]

Hello-

The reference chigger made to the clutch actuation can get confusing, VW's/914/901 use a push type clutch- that is the release bearing pushes on the pressure plate to release the clutch disk. 915 trans use a pull type clutch-the release bearing is attached to the pressure plate and the arm pulls release bearing that pulls the pressure plate to release the clutch disk. These references have nothing to do with the clutch arm and the way the cable acts on the arm. Now to confuse things more, I understand the 912E used a 923(?) trans that is like the 915 but uses a 914 style clutch (push). Pretty rare and I have not seen one in person.

You are correct about the 923. I have one of them in my T3 - it's a nice thing to have :-).


We still haven't talked about the 911/01 trans, it's a mix of the 901 and 915 for '70-'71 only. As I understand it, it's a 915 with a 901 bellhousing so it's a good way to go but much harder to find.

Not quite.

Beginning in Aug. 1969, Porsche did use an updated transmission from the 901 called the 911. However, it is basically a 901 with a slightly reinfornced casing. Not *that* huge of an improvement in the durability/strength/etc. department, but notable nevertheless.

The 915 (which started in Aug. 1971) is a _totally_ different animal. It is _not_ based on the 901, but rather on the 916 racing transmission. The shaft center-to-center spacing is perhaps the biggest difference - it is 76mm instead of 68mm, making larger, stronger, and more durable gear fitment possible. The bearings are significantly larger and have significantly more reinforcement, too.

The 1976 912E, with the 923 transmission, is based on the 915 transmission. However, as pointed out, rather than using a 225mm pull-type clutch, it uses a 215mm push-type clutch from a 914, making it one of the perfect transmissions for a T4 engine.

Take care,