IT WORKS! Put QG18 gears in your P11 TRANS! 56k take a nap.

[Coheed]

Here are the good pics. Anyone break 2nd gear ever? I don't think it was overwhelming power that did this, but I would like to find out what caused this so it doesn't happen again. 2nd gear looks to be the strongest of the bunch. But I always hit second pretty hard when having fun. I never expected it to break though

I'm always babying 3rd gear, and I don't ever grind gears or full-throttle upshift. And I also don't have wheel hop issues at all. Maybe it was just defective? After all, I did break one OEM axle shaft... snapped clean in half. Now I have Cardone new axles and I've broken one of those as well!

Anyway, here's the pics.

[canx2k]

mein gawt! That's HORRIBLE! This looks like something straight out of black hawk down! (and not the good part where orlando bloom dies either!!!)

[BenFenner]

Agreed, looks like 2nd gear.

The optimist in me thinks it might have been caused by something like Snickers said, where a C clip or something got loose and wedged itself between the gears but you where under power so instead of seizing the transmission the C clip got eaten by the gears, possibly separating the shafts a bit in the process. The gear teeth then misaligned and shredded themselves to pieces. It could have happened to 2nd gear even while you were in any other gear.

The pessimist in me thinks it was just a general strength failure, where the 2nd gears were either slightly defective from the factory, or you just over powered them.

[nissan crazy]

or possibly clutch choice had somthing to do with it ......never know

[morgans432]

that clutch you put in was a pretty nasty clutch correct? nasty being pretty serious holding power and engagement

[cory]

ive have the splines strip out of the act puck disk w/ b15 trans bfore.

[ashtonsser]

yeah thats second gear alright, doesnt look like the gear shredded under power, more looks like something got caught in there like people are saying. Sorry to hear about that, if it sheered under power the teeth would be basicly completely gone and nothing left. At least thats what my 3rd gear looked like when it broke.

Time to find a QR18 trans and swap gearstacks, probably your cheapest option.

[Coheed]

Ya it looks like the input shaft was the weak link. There is no teeth left on it. And it broke under power. Right when I was about to push the clutch in at about 7000rpm. I think this was a factory defect, or just weakened over time. The transmission is in PERFECT shape though! The thing shifts now that the debris was taken out. There are no missing roll pins, no missing snap rings etc. So far, there is nothing in the shrapnel but gear.

The input shaft piece of 2nd gear is actually part of the shaft itself. You cannot replace it, the shaft is trash. This is the part that caused the failure imho. The gear is cast, and possibly had a small defect from the factory.

The '00-'01 QG tranny is the same, but has a 3.827 final drive. I am going to try that if I can find one. Otherwise, it looks like the later models all used the 4.176 final drive, which is the same as what I've got now.

Gears look like they cost about $100-$110 each new from Nissan, but the input shaft is still very expensive.

The good news is the QG tranny can be had for about $120 here locally for a 2004. And the rest of the transmission looks like it is in perfect shape! No other damage from the gear exploding! All the other gears look great, in perfect shape. And the only synchro showing ANY wear at all is 2nd, and it is extremely minor!

[Coheed]

Originally Posted by morgans432

that clutch you put in was a pretty nasty clutch correct? nasty being pretty serious holding power and engagement

the clutch I am using is very aggressive, but doesn't chatter very much at all, and is pretty smooth until really beaten for a bit. Then it grabs hard! It is sintered iron, so it is smooth when cold and gets more bite as it heats up. It is not that aggressive though. You would be pretty amazed to see it work, it is awesome, but it may have something to do with the failure.

[Coheed]

I am so freakin excited! I found a local 1.8 trans for sale. It is out of a 2000 GXE sentra. It has some miles on it though, but it has the nice final drive. And best of all, it is under $150

[Payu]

I have seen that failure on my car but in 4th gear.... With ACT sprung 4puc XT pp setup
I have seen it here on third gear too..
And both of the guys here have this kind of problems here when used with twin disc setups..so clutch can be one of the factors since TD setup doesnt hacve srung discs...

[Payu]

Final drive on all QR18 transmissions its the same as P11 FD there its an error on FSM if you make your own math you will see but you will be able too replace both gear stacks and use your FD

[Coheed]

yes, the final drive is the same on all but the 00-01 I thought. My FSM says 3.827 or something like that, and the nissan part numbers for the shafts are different.

[Octave]

when you get the tranny can you post the case and bell housing differences side by side? the fabricator in me is always turning his wheels.

[Coheed]

The bell housing is completely different. Different bolt pattern completely. The rear casing though is nearly IDENTICAL, other than the differential hump. The hump is missing on the non-lsd transmission.

Oh btw I picked up the tranny today. IT is from a 2004 1.8L with 33K on the odo.

The transmission rear housing is cool. With the bell-housing from the SR you can just swap the whole rear end if you want, and you have the non-lsd tranny. Since the gears and casing are so similar, the strength of the non-lsd should match that of the LSD. You can simply add a phantom grip or JGY LSD and this would be THE transmission to get. They are everywhere, and dirt cheap. This one I picked up for under $400 with tax out the door.

So if anyone ever gets really unlucky like me, you can find these transmissions everywhere. As long as your final drive gear is still good, you should be able to swap the stacks out. I am going to find out really soon. It may cost me some money to do this R&D but you know me... its all about the community right? So if this works, we will have another solution to a rare problem.

[Coheed]

Someone please help me understand this:
The number of teeth here is a bit confusing: both have a 4.176 FD
QG18DE: Final gear/pinion 71/17
SR20DE: Final gear/pinion 71/17

Ok but look at this:
Side gear/pinion mate gear:
QG18DE: 16/10
SR20DE: 14/10

What is the side gear/pinion mate gear? Am I going to have to swap this gear to work with my p11 FD?

[Coheed]

Ok so the side gear/pinion mate gear is the differential gears. That is pointless. I'm not using the differential gears! lol. Ok it is starting to make sense. I was just praying that this was going to be an easy swap. Just remove the shift forks, take out the stacks, swap over, put back together. Done.

Anyone see any reason why this would require any more work than that?

[Payu]

Yo will have to take apart both transmissions and swap the gear stacks i already did the R&D you wont be using the differential of the QR transmission neither both of the cases of it just the gear stacks and the forks if you want to....

[Coheed]

Sweet. Can't wait!

[Coheed]

tomorrow the other transmission gets torn down. Until then, feast your eyes on more carnage of this P11 box...



Here you can see that the 2nd gear on the input shaft IS the input shaft. This is what I think failed. A local shop had an input shaft failure on a non LSD tranny, the input shaft sheared off right at the input shaft front bearing.


This is just a pic of the 3rd gear syncros, 2nd gear synchs looked amazing for the pounding they have seen though. I was very impressed. There is some obvious wear, but it seems fitting considering the 100+ drag passes, and daily beating.