I have an 03 350z base with 79k and 6 speed,
I need to know which years are compatible and out of those which would be best. My second gear is popping and sometimes a gear will grind.

I plan on buying one used but will get a new one if I can afford.

 

standard DE transmission that is a CD009 is a direct replacement. It's just a revised version with better synchros.

 

I thought only the transmissions found in the 07+ had the CD009 classification. Please correct me if I'm wrong. Thanks. My 5th gear grinds also when tranny is cold.

 

You are incorrect, lol. I got my cd09 out of a 05 or 06. I think in 07 the slave cylinders change up a little bit. 07 has the internal where as the earlier models have the slave on the outside. I might be mistaken a little bit on that, but I do know that some earlier models below 07 had the cd09.

 

Thanks for the clarrification..

 

+1.

All transmissions that are cd001 through cd009 are all DE transmissions. Anything that goes on the HR engine is a different transmission. The cd00x designation is just a number they use to show the same transmission has been upgraded internally.

 

Would there be any benefit to upgrading to the HR tranny with modifications?

 

no internals are pretty much identical, couple different sized bearings and a different sized input shaft but no benefit. someone did it and required a ton of work but he had his own stuff to do the machine work and got the tranny super cheap iirc. the cd009 has proven itself past 1000 whp