Samurai Speed's Transmission Dissected

We've been very busy with the renovations on our new shop that we hadn't had a chance to dig into our broken tranny. That and the fact that we ran into some problems with pulling the gears apart -- we had to send it out to someone to have it done as the gears are pressed on super tight.

Well, we finally were able to get it apart and take a closer look at it. Big thanks to Eddie, our head mechanic, for busting his butt on it.

Here are some photos where you can see the damage to the first gear itself as well as the gear shaft...







After closely examining the broken first gear, and seeing a pattern of hairline cracks in different places throughout the gear, it is our conclusion that the damage to the gear is most likely NOT from wheel hop. (Hence the reason there was no wheel hop on the launch that it broke.) It appears as if the residual damage is simply from LAUNCH CONTROL ITSELF.

The LC process seems to put so much pressure on the gear that over time it produces fractures and then ultimately the teeth break off. Using launch control then becomes like RUSSIAN ROULETTE... if the gear comes to a stop where you are about to perform another launch, and that position on the gears does not contain an existing fracture, then you'll most likely not experience breakage from that actual launch; however, that new launch could certainly produce new fractures of the gear near that position where most of the stress was placed from LC.

Remember how my car had over 100 launches on it? And yet others broke from 20 or less launches? It's literally called LUCK. It my case, the gears happened to not come to rest (before another LC was going to be performed) where previous fractures had occurred. So the pressure that new LC would put on the gears was being done just as if the car had never been launched before. It was literally like playing Russian Roulette. If the gear came to a stop directly on top of an existing fracture and you launched again, your odds were very high that the gear would break on that launch. Not always the case as some spots possibly took multiple launches with existing fractures, but it certainly appears that if you happened to stop the car with that pre-fractured area of the gear teeth lining up on the gear shaft and you went to launch the car that it was most likely causing the breakage.

So it certainly appears that it's not just wheel hop causing the damage and that it's the pure force of launch control itself that was putting the stress on whatever teeth were lined up on the shaft at the moment of impact. Bottom line... the gear materials don't seem to be strong enough to withstand the force of launch control.

We're now in the process of having a stronger first gear and shaft made... not only of stronger materials but also cryo-treated. Once we get this made my goal is to take the car out and do 100 LAUNCHES IN A ROW on the same day. We'll have to let the car cool down with temps, etc. when needed, but the goal is to bang the hell out of it to really test it. Then we'll open the tranny back up and analyze the condition of that 1st gear and shaft.

We'll post more news as it becomes available.

Samurai Speed's Transmission Dissected! - NAGTROC - The Nissan GT-R Owners Club

That sux nissan didn't do something about this. You would think they broke at least a few gears in their testing.

PSN ID: Phatchance249

Oh silly shops thinking cryotreating makes a more durable gear....

Shame shame...

But more shame on nissan for not making that gear a tidbit higher torque capacity...its not even the FD....



Buildin' n' Boostin for 08' - Alex Richards

Wow It is cool to see. I was wondering exactly what parts were breaking in the trans.



FORGET GIRLS GONE WILD WE HAVE GOVERNMENT SPENDING GONE WILD!

But but but imports are so much more reliable than domestics. I have yet to shatter or even strip teeth from
a forward gear even with 6500 RPM clutch drops. Im sure its only a matter of time before non LC
transmissions do the same thing.

mitdr774 wrote:But but but imports are so much more reliable than domestics. I have yet to shatter or even strip teeth from
a forward gear even with 6500 RPM clutch drops. Im sure its only a matter of time before non LC
transmissions do the same thing.

That is kind of apples to oranges man. An AWD car will break parts where as a 2wd will just melt tires. Granted I have yet to hear of anything breaking on the 5.9liter jeeps like I have from launching it. Even then it is apples to oranges



FORGET GIRLS GONE WILD WE HAVE GOVERNMENT SPENDING GONE WILD!

Look at the torque rating of the F23. I far exceeded it and still never broke a gear during a launch. I know its not AWD but its still one hell of a sudden load to just throw at the gear. I dont frequent VW forums but I have not heard a whole lot about the DSG trans in the R32, even when turboed and making huge numbers, doing this. I could be mistaken though as I dont frequent those forums.

does this finally silence the nissan fan-boys on the GTR vs C6 Z06 debate? The vette will not break gears after 100 launches on a stock drivetrain....

mitdr774 wrote:Look at the torque rating of the F23. I far exceeded it and still never broke a gear during a launch. I know its not AWD but its still one hell of a sudden load to just throw at the gear. I dont frequent VW forums but I have not heard a whole lot about the DSG trans in the R32, even when turboed and making huge numbers, doing this. I could be mistaken though as I dont frequent those forums.

agreed, the only issue I ever had with the F23 was the differential and the 2 times I blew em up it was my fault @!#$ around



LE61T PTE6262 Powered

mitdr774 wrote:But but but imports are so much more reliable than domestics. I have yet to shatter or even strip teeth from
a forward gear even with 6500 RPM clutch drops. Im sure its only a matter of time before non LC
transmissions do the same thing.

But but but, you also arent making like 400hp on your awd car either.


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cavmania wrote:

mitdr774 wrote:But but but imports are so much more reliable than domestics. I have yet to shatter or even strip teeth from
a forward gear even with 6500 RPM clutch drops. Im sure its only a matter of time before non LC
transmissions do the same thing.

But but but, you also arent making like 400hp on your awd car either.

But but but the Getrag has been shown to handle well over its torque capacity rating while being abused at a track.

I have never been a fan of the GTR as it is ugly, overpriced, non driver oriented, over hyped pig of a car. To release
a car that breaks the gears in the transmission with stock power is a major problem. Its only a matter of time
before the non LC cars start doing this.

It would be like GM putting the base Solstice rear diff. in the STS-V. That part just wouldnt be up to the task expected
of it.

mitdr774 wrote:Look at the torque rating of the F23. I far exceeded it and still never broke a gear during a launch. I know its not AWD but its still one hell of a sudden load to just throw at the gear. I dont frequent VW forums but I have not heard a whole lot about the DSG trans in the R32, even when turboed and making huge numbers, doing this. I could be mistaken though as I dont frequent those forums.

These things are designed and manufactured with factors of safety and material resistance factors to account for imperfections and material flaws. The torque rating is a very conservative rating which basically says next to no trans, even the ones with flaws in workmanship, and poor quality materials, will ever break below it's torque rating. That being said, the parts that are average or above average quailty can take way more load than what they are actually rated at before they break.

AGreed but Nissan chose to use a trans that did not have sufficiently strong enough gears to hold. Nissan went cheap and as a result the teeth are breaking off of the gears. F23 is rated at about 175tq and they have held up to well above that. It would be like GM putting a NVG1500 behind the 8100 or Duramax. Nissan just didnt think it through when it came to strength, they went cheap and decided to play the odds game.

You'd think that for the cost of the GTR, it would have gears made from some rare outer space metals in the transmission!!!




SPD RCR Z - '02 Z24 420whp
SLO GOAT - '04 GTO 305whp
W41 BOI - '78 Buick Opel Isuzu W41 Swap

mitdr774 wrote:AGreed but Nissan chose to use a trans that did not have sufficiently strong enough gears to hold. Nissan went cheap and as a result the teeth are breaking off of the gears. F23 is rated at about 175tq and they have held up to well above that. It would be like GM putting a NVG1500 behind the 8100 or Duramax. Nissan just didnt think it through when it came to strength, they went cheap and decided to play the odds game.

and charge $20K for replacement trannys....



P&P Tuning
420.5whp / 359.8wtq

I don't think its a matter of cheaping out. The dsg transmission is a fairly new design. Although nissan should have foreseen the first gear braking like this. I was kinda expecting one of the clutches to break instead of the gear.

DSG isnt new when it comes to advances in auto technology. How long has VW had it? BMW SMG gearboxes have been around for quite a while to.

mitdr774 wrote:But but but imports are so much more reliable than domestics. I have yet to shatter or even strip teeth from
a forward gear even with 6500 RPM clutch drops. Im sure its only a matter of time before non LC
transmissions do the same thing.

They are, just because the GTR is not doesn't mean all imports are unreliable. That's just closed minded and ignorant.
Yes Nissan dropped the ball on a car that should be worth the asking price, but that doesn't support your very smug, very vague assumption, and generalization that because this one car has poor engineering that automatically makes domestics better or equal to all imports. Or that imports suck…that’s an opinion. I agree this car has poorly thought out engineering, I’m also on the side that defends the entire Corvette line as the best performance deal on the planet PERIOD! But sadly, car-for-car, imports are in fact “so much more reliable”.




"Formerly known as Jammit - JBO member since 1998" JBOM | CSS.net

Well apparently you didn't see it as a joke. I used to work in a Nissan dealer and have worked in GM dealers. I can honestly say that I would take a GM over any newish Nissan. At the same time I would take a late 80's early 90's Trooper or Samurai/Sidekick over the same year range Jimmy/Blazer. I also find GM vehicles to be much easier to work on than the imports, then again that is what I have always worked on by choice. Am I still to closed minded and ignorant for you??

and doesnt GM and the domestics always get criticized for sticking to what works? pushrod v8s, leaf springs and solid rears




__________________________________________________________________

Where I work: HP
What I take for Memory and Focus: Focus Fast

1996blackHB wrote:and doesnt GM and the domestics always get criticized for sticking to what works? pushrod v8s, leaf springs and solid rears

That's what works? Depends what you're building.

wysiwyg wrote:i would say they bang, they don't really pound so much. but if
you want to bump, then they will bump and hit real hard and a lot good.

LOL

I want my big 6 and 8 cylinder engines to have low end torque so I want a push rod engine. I cant recall the last time a vehicle had a solid axle. Live axles are a proven system that in many cases is well more than enough for the job. Easier and cheaper to manufacture as well. I want my truck to have leaf springs in the rear and torsion bars up front. Push rods, live axles, torsion bars and leaf springs are all proven to work well. Now I will also say that I do like the LT5, DOHC engine used in the early to mid 90's ZR-1.

you know, just to think outside the box.....

is it possible that it would cost nissan less to replace a gear, then perhaps a diff? perhaps its best to have the breaking point at that gear instead of some other component. just a thought

They should still be able to take the abuse though. It seems the problem is a major one on many of the vehicles. I don't think it's right that they sell a car, then you use it and it voids the warranty. Then they charge you $20k for a new tranny? No thanks. I think they should have built a stronger transmission, or got rid the launch control before launching the vehicle. You don't buy the cheapest go-fast car that can do 0-60 in 3.3 seconds, and not use it for that EVER.... And I really don't like the fact that the car auto-shifts. I know it's faster and blah blah blah, but personally I would take a z06 over a GTR just because of the lack of the stick shift. It makes me feel more... in control I guess?

wysiwyg wrote:i would say they bang, they don't really pound so much. but if
you want to bump, then they will bump and hit real hard and a lot good.

LOL

ChrisH4Life wrote:

1996blackHB wrote:and doesnt GM and the domestics always get criticized for sticking to what works? pushrod v8s, leaf springs and solid rears

That's what works? Depends what you're building.

Oh, say a GTR Murdering ZR-1?


Chris




'02 Z-24 Supercharged
13.7 @102.45 MPH Third Place, 2007 GMSC Bash SOLD AS OF 01MAR08