902/1 vs 902/02

[emedina]

I would like to know what is a better transmission, 902/1 or 902/02? Thanks

[WFBowen]

From the factory book:

Just guessing that the case materials may be different but they sure look the same to me.

[oldie44]

The difference between the 2 transmissions is the the way the shaft for the spider gears inside the differential is retained.
902/1 is the first version which used a cross tube that was secured by the axle flange retaining bolts. Used up until about 1966
902/02 used the next version (called simplified) which eleminated the cross tube and used axle flange bolts with projects on the ends that fit into a hole in the spider gear shaft. Used up until 1969.
Both systems had their weak points. Easy to convert from one to the other if you have the parts.

[WFBowen]

Ken
Thanks for clearing this up.
Bill

[oldie44]

If you have a 902/02 check the axle flange bolts for wear on the projections on the ends. They wear out after about 100K miles. Disaster if they break off. I've got pictures if you want to see.

[WFBowen]

Ken
Upload some pictures. This is good info for those who might be searching in the future.

[oldie44]

The first pictures shows the early parts on the left and late parts on the right. There are other parts in the differential but shown are the unique ones.
The early sytem used a cross tube which was attached to the shaft with a roll pin. Shown are two punches for removing and installing the roll pin. The axle flange bolts were attached to the cross tube but there was clearance so the flanges could rotate. Thrust was taken by the special washers that were grooved to retain an oil film. The flanges were not sealed against oil leakage so they had aluminum plugs with o-rings.
The next system used flang bolts with projections on the ends to retain the cross shaft. It was a lot simpler but the projections would wear out after about 100,000 miles. Well known in PCA circles back in the 1970s. If you have a transmission with this system, you need to check the condition of the bolts.
These two systems are the only options for aluminum case transmissions. Mag case can use the retaining block/roll pin system introduced in 1970.

[Steve F]

Nicely done sir!

[WFBowen]

Ken:
Great information. Thanks for taking the time to explain the differences.

[Adsby76]

Great info