Two years at 400+ wheel HP and my NA transmission is finally dead!

Yesterday afternoon I was running across the city to get to the post office before 5PM. One of the main cross streets turns into an expressway so the speed limit goes from 60 (KM/H) to 100. As the light turned green I was stuck behind some douche in a Camry that didn't seem to understand that going 50 KM/H in the left lane of a 100 zone is a bad thing. With the big diesel riding my butt so close I could see the herpes on the guys lips, I signalled to switch lanes.

Of course, just as I was pulling out, the guy driving the diesel *****-extension behind me thought it would be a good idea to move lanes as well and punch his throttle. I'm thinking "WTF?". So I dropped it into third, went WOT and unleashed the beast. I had very little room because my off ramp was the next one otherwise I would have been a little more responsible. Missing exits also means a round trip through prime traffic jam area.

Coming up on about 5500 RPM there was a noise that was a combination grinding-clunking-banging, at which point the car stopped accelerating. I tried 3rd again...no dice. Nothing in 2nd either. Finding 4th, I took my ramp and luckily had all green lights to a local parking lot.

Looks like I don't have any gear but 4th so I think I've blown the cluster shaft to pieces. The transmission is crushing rocks everytime it rotates...

I have a spare NA transmission which I will swap into the car today or tomorrow. Ultimately though I will be upgrading transmissions but that will end up in one of my build threads. I'll update this thread with carnage pictures of the broken unit because I think it's going to be impressive.

 

Ouch. I can't wait to see the pics.

Maybe you can help me with my annoying little transmission problem...

https://www.rx7club.com/showthread.p.....+makes+noise

Sorry for the thread jack. Nobody could ever answer my question.

 

I rarely enter the FC section, but that story was worth it. Looking forward to the pics of the carnage.

 

Pretty much exactly what happened to my transmission but in first gear.

 

ouch, but that sucks to hear. But let's see how your transmission build goes.

 

I'm not too worried or broken up about it. Had to happen at some point and I have a spare unit.

I'll drive the spare unit kind of easily while I await the parts to swap in a more suitable transmission. A TII unit will bolt right in but that's not my style and I don't want TII parts on my car.

 

At least you didn't nail the gas and hear your engine explode (unlike me)!

 

Are you planning to modify the N/A transmission if you do not plan on using a T2 one?

 

So how much whp did you end up with on that setup? I watched a dyno video from your car a while back and it wqas like 379rwhp. Did I miss it?

 

Nicely done bro. Glad to hear that it lasted that long at 400hp. Hoping to see some broken shafts and bare gears in pics. lol.

 

i think thats your problem right there! when i'm late to the post office, i take the mercedes

yeah if it makes bad noises just spinning you are going to have some cool pics. when we raced the FC, we managed to break an NA trans too (i dunno HOW at 160rwhp?) i just recently tossed the parts, but we took the teeth off of 3rd, shrapnel kinda ruined everything else.

 

I think a lot of us have expected this story. Your n/a tranny really did last a while though. I've been through 2 in my car, but that's mostly from stupid mistakes.

I really liked this quote:

'I'll drive the spare unit kind of easily while I await the parts to swap in a more suitable transmission. A TII unit will bolt right in but that's not my style and I don't want TII parts on my car."

Looking forward to updates

 

and they say N/a drivetrain can't handle any power thats awesome though two years at that much power.

 

lol wow. You should upgrade your drivetrain. I think I only have about 200whp and i already detroyed two of these.

I have at2 tranny and driveshaft grinded down to fit a na rear end. It sucks, it cant handle teh power for t2.. So If you have 400hp, OMG expect to be breaking these stubshafts, youll be stranded if you have open diff!!! I was able to drive home 140 miles with onewheel drive from a drift event on awelded na diff.. the welds held up the onewheel drive pressure.. But yeah those na stubshafts is waacksaucee

 

Under any REAL form of abuse, it can't. Simple as that. My NA trans was MINT before I boosted my car, no synchro problems, no grinding no nothing. It took a couple months of hard launches with 225 Falken Azenis's and getting sideways at U turns and intersections for first gear to finally give out.

 

^"It took a couple months of hard launches with 225 Falken Azenis's and getting sideways at U turns and intersections for first gear to finally give out." so... it held up then.

 

lol, that sounds bad ***. take pictures along the way.

 

+1 Yes, Aaron, take pictures.

Unrelated - I've taken a manual tranny apart, just to screw around. I'm lost on how synchros do their job, so if you feel like it, turn it into a lesson with a couple of pics. Haven't found any good links to this stuff.

 

aww, thats awesome.
i too am curious to see what alternatives to a t2 tranny you come up with.
i like my n/a stuff, not sure if i want to just get rid of it.
but yeah, two years when people say it can't be done...bravo.

 

what tranny are you looking at? T-5 or T-56? There is a guy in the 20b forum that did a T56 conversion.

 

yeah i've grenaded one, the result from too many high rpm launches. did you notice any increased noise from the tranny in recent days/weeks?

 

I'm sure when you pull that trans apart you'll see lots of broken teeth, and some awesome carnage. The same kind of thing happened to me with the 5 speed Mazda trans in my 2000 F150. I'm curious to know what path you'll take for the new trans. I'm also looking to upgrade the trans in my car without going the TII path. I have a spare NA tranny that needs some new sychros and bearings. I was going to take it to trade school with me and rebuild it there. I wondered if there where parts available to upgrade the stock NA trans, like heavier bearings and synchros. Maybe even a heavier duty first gear. That's the one that takes the abuse.

 

I have another NA transmission sitting in my shop right now that I pulled from a parts car yesterday. It's going onto the car since it bolts right on and I'd like to drive it. I'm going to try and avoid using a TII transmission if at all possible. Read below.

THe best dyno was 392 to the wheels, but since then I've done a bit more tuning and it's a little over 400 HP at the wheels. What I think really signalled the death of this transmission was a tuning session last weekend. I cleaned up a few dirty areas of the map, gave it a lot less fuel in the midrange, a bit more timing and smoothed out some lumps. The result was an obvious increase in midrange power. Now that I'm done running 13 PSI and it's tuned about as well as it can be, the boost controller is in the mail. Hence I'll need a stronger transmission once the boost goes up.

Well, maybe I won't drive the spare unit easily but I won't blow it up before the weekend of May 17th. There's a local RX-7 meet and it will only be the 2nd one I have attended since I finished the car.

TII stub shafts are pretty weak at those power levels as well. A set of sticky tires and a good launch will roast them just as easily. It's funny, I've broken several driveshafts (even one said to be "unbreakable" by the builder) but this is the only NA drivetrain component I have ever roasted due to power.

I'm leaning towards the T-5 route. I can get a built T-5 for any power level for the fraction of what it costs to totally work over the Mazda unit (whether NA or TII). What will ultimately make the decision is where the shifter ends up. If it turns out I need to hack up the tunnel and the shifter moves a few inches, then I really have no choice but to use the TII transmission. I'm not willing to start cutting apart the shifter area (with all my new trim and carpets) to try and fit a shifter. But I would really like to stay away from TII stuff.

Yep. That's why I expected this and am not worried. A track session last year (last night of the season) resulted in a bit of a whine in 1st, 2nd and 3rd. So the transmission was already a little unhappy.

 

Someone had mentioned in the thread showcasing damions stright cut t5 dogbox that the tail housing off of the early nissan z series is longer than the normal t5 tail housing, i dont have exact measurments but looked like it would be very close.

 

Aaron what about a RX4 tranny?They are known to hold a lot of abuse and power and they are almost identical to a Turbo 2 tranny,the only problems is that the shifter sits forward a little bit but that can be modified using a second gen tail housing,What the hell you can even use T2 internals and still a RX4 tranny not a T2 tranny.