Last week I took my 008 6MT to Team Rip Engineering (TRE) to tear it down and see what we could do to beef it up to stand up my my drag racing abuse with my new setup. TRE is a well know DSM transmission builder in Michigan and one of my good friends is employed there so I was able to assist in the tear down procedure.

What we found was both suprising and pleasing. As you'll see in the following pictures comparing a GETRAG 6-speed out of a 3000GT VR-4 (VERY stout transmission), our 350Z 6-speed is no slouch.

First we'll start with the trans right after we pulled the case off of it.


Now with the shift rods and forks removed.


Now to the good stuff...gear comparisons...

The first and second gears in this trans are HUGE. In TRE's opinion they should be nearly unbreakable.

On to third gear which has gotten some crap lately since a few people have broken it. Third is plenty beefy and nearly identical to the GETRAG third gear. From left to right we have third out of a maxima, GETRAG, and 350Z.


Fourth gear is more of the same, still plenty beefy and in this other angle to can clearly see that the 350Z fourth's (right) teeth are just as thick if not thicker than the GETRAG's fourth (left). Fourth out of the GETRAG is larger in diameter due to it's different gear ratio.


Finally, we have a 5th gear comparison, the two darker colored gears are the 350Z fifth and the lighter one is fifth out of the GETRAG. The 350Z's fifth gear is both thicker and has larger teeth than the GETRAG. The reason for this is that when gears 1-4 are selected, 5th is the initial reduction gear in the trans and thus 5th gets a good amount of abuse since the only time it's not used is in 6th. After about 40K hard miles, my 5th gear teeth have some spalling on them and I will be replacing 5th as a preventative measure.


To further show how beefy our 5th is here it is again from left to right, 350Z, GETRAG, and a Maxima 5th gear.


Here's a little bouns that we have on our aluminum shift forks...bronze inserts. They cut down on fork wear and not long ago were mainly only available as a performance aftermarket add on. Very cool.


As for synchros (which are the well known problem plaguing many 350Z transmissions), after 40K miles my synchros are in really good shape and I doubt we'll be replacing any of them.

Overall John (owner of TRE) and I were very impressed with the internals on this trans. He's going to do some work on the gears over the next couple weeks to make them even stronger and modify the shift rods and forks to make the trans shift even better. (It already shifted very well). If we have success with this "built-up", He said he'd consider doing work on more of them.

In closing, contrary to popular belief on this forum, our 6MT is NOT a weak POS, and it looks very promising as far and big power handling goes.

 

Thanks!

 

Wow thats really interesting. But you can't say from just looking at the size and how "beef" the components are, but what they are made of. Getrag transmissions may use better quality materials then the 350's tranny

 

While that definitely could be the case, the dimensions of the gears seems to be in line with other very beefy transmissions. The strenth is supported by the fact that only a very small handful of people have even broken this trans. Furthmore, the people whom have broken them typically haven't torn them down to do a failure analysis. So we really don't even know what exactly broke.

EDIT: Typically the gear design is the primary determining factor in failure threshold, rather than an insufficiently prepared gear steel.

 

That is awesome... very interesting. Does your friend have any hypothesis as to why so many people have problems with the sychronizers wearing down?

 

We talked about it a bit, but I don't remember in detail what he said. It seems to me that originally they "under snychro'd" the trans by putting at most, double cone synchros on only second and third, and now the lastest revision has triple cone snychros on second and third, and doubles on most of the rest.

 

Great thread! Thanks for the info and confidence in our tranny.

 

This thread will come in handy to a lot of people, nice job

 

Bri, Thanks for that great writeup.
The Z community always benefits from sharing knowledge like this.
--B

 

 

Im will be coming back to this thread very often, I hope you guys learn something we can all use.
Thanks

 

Can he change the gear ratios for turbo cars?

JET

 

Thanks! Just goes to show how bad some people really drive it.

 

No, that would require an entire new gearset and shafts. He works on existing components and does limited custom work.

 

I dont think that is a very fair statement wtf no turbo. Yea great the gears are really strong perhaps, but he hasnt said much about the syncro's and that really seems to be most peoples problems. Just because I myself and many other people have had to have their transmission replaced, doesnt mean we beat on it necessarily.

This is a very imformative post non the less, and it will be interesting to see how he alters your gears, and "builds" your tranny to withstand you drag racing.

 

Thanks for the break down on our transmission and gears. Lots of great info and pics.

 

Great post, really informative. I look forward to checking in on the progress with your tranny. Thanks for posting...

 

Great post, makes me feel good about my trans..

 

Good stuff Brian, looking forward to watching your build

 

.....as I am about to ask Nissan to put #5 !!! in my -Z-.

It has always been a 5th synchro problem for me.

Can you tell us why the 6MT is (sometimes) very notchy in the shifting department. Pics?