About the 912E

Transmission

The 912E transmission is unique to the car and is referred to as a 923 transmission. It is very similiar to the 915 transmission from the 1976 911. From the 912E Workshop Manual, Section 30, page 30-01; “A five speed manual transmission is installed in conjunction with the four cylinder engine and only differs from the 1976 model transmissions 915 in a few details. Clutch guide tube, clutch operation, input shaft with smaller clutch hub splines, different ratios.”

912E transmission

The ratios shown for each gear in both the 923 and 915 transmissions indicate that 1st, 2nd and 3rd gears are identical in both transmissions and have the same gear set designations for both (AZ, HX and NT respectively). This data is taken from the 912E Workshop Manual and the 911 Workshop Manual, Volume IV (915 Transmission). There does not appear to be a separate workshop manual for the 923/02 transmission.

Summing up the 912E transmission, it can be concluded that it is more of a 915 tranny than a 901, and with the exceptions noted above, is rebuilt using the same parts that are also used in the 915.

Grinding from 1st to 2nd gear?

The synchros in the transmission can wear out, which is very common on cars of this age.¬†Shifting slower makes the synchro’s job easier, but to solve the problem permanently, the gearbox needs to be refurbished, which can be fairly expensive. Before spending all that money, you may want to try replacing gear shift bushings, and using SWEPCO 201 transmission fluid - some owners swear by it, saying it has been known to make a marginal trans into a smooth shifter!

Another temporary fix: When taking off from neutral, pull the gear stick toward second (just a little, without actually engaging second) and then it should go smoothly into first.