gear box

[Demetrios]

I own a 1973 240 Z. Few years back, I decided with my mechanic to replace the four-gear box with a five-gear box of a 260 Z, without changing the differential. I did that because there was a sound from the original gear box on the fourth gear Now, I think that this was a mistake, so I am wondering whether it would be better to leave the five gear box from the 260 Z and replace the differential with a 260 Z differential or, leave the 260 Z gear box with the 240Z differential as it is or finally, try to locate a 240 Z gear box and bring the car to its original state. Could anybody help me to locate a 240 Z gear box and generally speaking, give me an idea as to what to do?

[seerex]

hhm first your 5 speed came from a 280 not a 260 <i believe the first 5spds were options on 78 280z>, just for info only , finding a 240 4 speed is rather easy , if you check ebay , on this website or zcar.com i am sure you can find one very reasonably or possible free, if you are changing it just for value or being original , then change it back to the 4 speed unit just make sure its a 72 or later 4 speed , they are better from what I have read but if you are thinking about putting a newer rear end in the car from a 260/280 I wouldn't , no reason to do it, actually unless you are looking to make it a show original car, I would leave it the way it is now , better gas milage and best combo for a stock or very close to stock setup , hope I helped Jeff good luck:geek:

[Ed]

I would leave it also. Most 4 & 5 speed gear boxes are identical in gear ratio 1-4. The fifth gear is a overdrive, which is better for gas milage. A lot of people have changed their 4 speed for a five for that overdrive. And when it comes to the differential unless it is going bad you should leave it alone, just change the gear oil.

ED