[Spaz]

The transmission that came with my 1974 GTV had a broken drive gear assembly. (I am unsure what vintage the transmission is) I took it out to find there was no gear on the shaft at all. I located a suitable (I thought) replacement. I finally came to swapping it in and have encountered difficulty. The transmission is out of the car and I placed it in gear to rotate the output shaft and tried to insert the assembly into the hole but it appears to bind. I am not comfortable applying too much force to it. It does not seem to want to mesh. Are there possibly different gears in terms of tooth count? Or are the internal gear and gear count on the assembly a matched set?? Any help is greatly appreciated.

 

[Spaz]

Found the answer on the transmission forum. As I feared a matched set. I have no idea what gear is in the transmission now.

 

[alfaparticle]

Here is a picture of the gears for a 4.1 axle.

 

[Spaz]

Thanks. my drive gear is 13 tooth as on your picture. The helical is a lot finer than what you show.

 

[alfaparticle]

The finer helical is most likely for a 4.56 which is the original ratio for your GTV. So you need a speedometer drive gear for a 4.56. I think that all Spiders sold in the US between 1973 and 1979 had 4.56 axles so you need one out of one of those. I have a spare. I can mail it to you and you can pay me a nominal amount if it works or return it if it is not correct.

 

[Spaz]

The helical has 8 teeth so I need an 18 speedo drive??? No idea what car the transmission came from

 

[Alex]

18 teeth on the speedo drive gear and 8 teeth on the output yoke indicate a gearbox originally matched to a 4.3:1 ratio rear axle from a Berlina. Desirable for those who have swapped to that ratio. Refer to the current thread in the Transmissions section for details of other matched gear sets.

I have a new output yoke with 6 teeth for 4.1:1 (2000 GTV) rear axle if needed, although anyone with a junk gearbox should be able to provide you with what you need. What ratio is your axle?

 

[Spaz]

That makes sense. The fellow I bought the car from stripped a few berlinas. He may have the part in need. Thanks for the great info.

 

[Spaz]

If anyone has one, I need an 18 tooth output gear. I have a 13 if someone could use a swap.