Once your parts kit has been ordered, the next step in your WEVO 356 5-speed conversion is to source your donor Porsche 901 family transmission. Parts harvested from the donor will be used along with your 5-Speed kit parts to build the finished 356 5-Speed transmission.
Four different Porsche 5-speed transmissions can be used as a donor. They all have subtle variations, so understanding the donor models is key part of preparations. More than 215,000 vehicles equipped with the Porsche 901 transmission were manufactured, so there are plenty of core transmissions available. Even if (as Porsche claims) 75% of all 901-equipped donors Porsches are still driving, discounting those cars still leaves us with more than 50,000 potential donors!
Porsche 901 Transmission
The first version of 901, commonly known as the “Chilled Cast” version, is an all-aluminum casting used in the rear engine cars (911 & 912) from 1965 to 1968. It was available in both 4- and 5-speed versions. You will require a 5-speed version to have all the parts needed.
Porsche 911 Transmission
The second version of 901, commonly known as the “911 transmission”, is an all-magnesium casting that was used in the rear engine cars (911 & 912) from late in 1968 through the end of 1971. The 911 transmission was available in 4- or 5-speed versions. You will require a 5-speed version to have all the parts needed.
Porsche 914 Tailshift Transmission
The third version of 901 is commonly known as the “914 Tailshift” transmission, that was cast in magnesium and used in the first editions of 914-4 and 914-6 cars during 1970 thru 1972. The 914 Tailshift transmission was only available in a 5-speed version.
Porsche 914 Sideshift Transmission
The fourth version of the 901 is commonly known as the “914 Sideshift” transmission, also cast in magnesium and was used from 1973 to the end of 914 deliveries in 1976. The 914 Sideshift transmission was only available in a 5-speed version.
Further Transmission Considerations
Of these four versions, the 901, 911 and 914 Tailshift are the most desirable donor transmissions. These three versions will yield every part required to complete your 356 5-Speed kit.
The 914 Sideshift transmission will supply all the gears, shafts, sliders, hubs, shift forks, spacers etc, but only one of the three shift rails required and therefore require a few parts from another source. Although these transmissions are not a complete donor, they are also the newest of the donor cores and should not be overlooked as a great source of majority of the parts at economical prices.
The beauty of the 901 family of transmissions is complete modulatory of the design and the important fact that parts can be interchanged from all models. There is a wide variety of original ratios available from the different model four- and six-cylinder engine applications and there is a good range of new ratios also available from the aftermarket gear manufacturers.
Rebuild components for 901 series transmissions like sliders, drive teeth, synchro rings and bearings are all still readily available and, with the exception of a pitted CWP gear set or internal corrosion from poor storage conditions, nearly every donor core can be restored to good functional condition to build a 356 5-Speed.
There are some subtle technical variations in the assembly dimensions of the different versions and these are covered in the technical notes and guidelines for assembly.
Once you have your donor core you will need to establish the condition of the core and make provision for any repairs that would affect the operation or reliability of your new 356 5-Speed transmission project.
There are no special requirements for standard 901 series parts used for the 356 5-Speed transmission. The evaluation of condition would be the same if you were servicing that 901 transmission to be installed in the original vehicle.
The safest route is to work with an experienced Porsche transmission builder. They can complete an inspection of the components and make the recommendations of any replacement parts required.
If you are experienced and confident with the servicing of 901 transmissions, the donor parts for the kit should be reviewed for serviceability in the normal manner expressed in the Porsche factory manuals for the 901 series of transmissions.