7)The tapered surfaces on the first and second gears have been increased to provide smoother shifting. Synchro rings are almost the same size, take care so that they 're not interchanged. The first gear synchro has narrow slots and more oil grooves on the inside of the taper. The new type synchro hub for first and second gears has six centering lugs for the synchro sleeve. New type shift plates are flatter and have an inside groove into which the retainer spring is hooked. The two springs must run in opposite directions and be offset to one another.
8)The third speed gear ratio has been changed (starting in '66) to a higher ratio.
9)The main and pinion shafts are held in the bearing housing with a snap ring and cupped washer, starting with late 1967 models. Before these new type shafts can be pressed out, the snap rings on each shaft must be removed. The dished washer under the snap ring is preloaded - so be careful when removing them. To secure the new type main and pinion shaft after they are pressed into gear carrier case., VW tool 426 can be used to press on the washer and snap ring. (A 15/16" deep well socket will also work here.) Squeeze the rings after they are in place, to insure they are tightly seated, using pliers.
10)The washers and spacer sleeve have been eliminated between third and fourth gear on the pinion shaft. These have been replaced by a helical spacer spring on the newer type pinion shaft.
11)On this new type pinion shaft (post '67) a new type slotted nut is used, it has more slots and a soft edge that in staked into the shaft splines in order to keep it from working loose.
12)Fourth gear is now splined, instead of pressed on using a woodruff key.
13)New pinion bearing is of a larger diameter therefore the main case has also been modified to accept its larger size. The newer type pinion retainer is now a threaded ring.
14)The new IRS type differential has a split housing which carries the axle drive gears as well as the spyder gears. The drive end shafts on the differential are splined and have a snap ring groove for the connection at the c/v joint. The ends are also fitted with tapered roller bearings that ride in outer races on the side plates. Ring gear adjustment is made using spacer shims behind the outer race of the tapered roller bearings. VW tool is best for making this set up.
15)Years 1960 through 1968 - 4 speed standard gearbox were swing axle type. 1969 and later use constant velocity joints.
16)'66 - '67 gearboxes are best choice for high performance or off road use. They incorporate all the improvements made before introduction of the cv joint boxes. They can be identified by the ribbed design,on the brake drums. '68 4- speed standard gearboxes are still swing axle , (they have 4 bolt brake drums), but have brass shift forks and snap ring retainers on the main and pinion shafts making them less durable and therefore a less desireable selection, especially for off road use. Late cv joint boxes share these problems plus the fact that the cv joints and axles are not as rugged as the swing axle types. However, these late gear boxes are best choice for roadracing or slalom events where suspension advantages are gained.
Top: older type input shaft (rear main shaft)
Bottom: newer type. Difference in clutch seal area, in the middle of the shafts, can be seen.
