Broken ring/pinion gear, options??

[Pearldrummer7]

So, I cracked my trans open. Found that the pinion/ring gear are destroyed. Luckily, they're fairly cheap and nothing else seems to be damaged. Now the question is, besides doing less burnouts in it...how can I avoid this happening in the future?

I would imagine that someone makes a stronger ring pinion out there, no? Also, this is the time for a new diff, eh?

https://c2.staticflickr.com/9/8460/29320486985_b320ab9e5c_b.jpg (https://flic.kr/p/LEXagF)
https://c4.staticflickr.com/9/8377/29320487755_4d255d3af9_b.jpg (https://flic.kr/p/LEXauX)

[longislandwrx]

is it possible the lash was off? did you set it or did you never touch the diff?

I know you can get the gears cryo treated, I don't know if anyone makes beefier ring/pinion gears for the front diff. If you found some you might be halfway to a 6mt by the time they were installed.

[iblackwe]

I have heard lots about WRX 5MT transmissions being blown up under higher 300+ WHP applications but I always thought with the 818 only being rear wheel drive there would be 1/2 the about of torque on the entire system and thus wouldn't be much of an issue.... Unfortunately I will have to re-think that. But doesn't it make sense that there would only be half of the original strain on the system now or is there logic behind this I am not seeing?

[Zach34]

The WRX is splitting that 300+ HP between the front and rear diffs. Also, on full application of that 300+ HP, the front looses traction and the center diff diverts torque to the rear. We're putting all of the power through that front diff.

[twgab]

I did the same thing to mine about 6 months ago. I'm hoping my lash was off from when I installed my limited slip, so I made sure it was set up correct this time.
If it happens again, I thing a 6 speed will be the only option for the power I'm running.

[Bob_n_Cincy]

400 autocross launches (some with wheel hop) 195 whp
2 sets of axles
1 ring gear bolts came loose destroying the transmission.
Bob

[wallace18]

If you are over 250 RWHP use an STI trans. It will save you the headaches.

[Coolspot]

I have heard lots about WRX 5MT transmissions being blown up under higher 300+ WHP applications but I always thought with the 818 only being rear wheel drive there would be 1/2 the about of torque on the entire system and thus wouldn't be much of an issue.... Unfortunately I will have to re-think that. But doesn't it make sense that there would only be half of the original strain on the system now or is there logic behind this I am not seeing?

It's the opposite, on a WRX, the torque is spitted in half front and back, like Zack34 wrote, during hard acceleration, most of the torque is in the rear.

On the 818, we are using 100% of the torque on the Impreza front diff.

[Hindsight]

Does anyone know if any companies make a stronger front R&P? I have heard of stronger gear sets but not R&Ps.

[suttonb3]

So there's no agreed-upon way to keep the 5 speed from breaking?
I've almost got my second engine broken in (basically stock, minus intake and exhaust) but now I've got a high pitch whine in 5th gear. I checked my gear oil and there appears to be metal in it. The wife is not going to be happy...

[Hindsight]

Lots of threads here and elsewhere discussing the 5-speed. I can summarize by saying the Legacy GT 5-speeds are known to be stronger than the WRX versions. I believe I read the 08+ 5 speeds are stronger as well. You can spend like $5k to have PPG gears put into a 5 speed as well. Or you can get a 6 speed.

From observing many posts here, launching the 5 speed appears to be what brings their demise quickest. People who launch hard and do burn-outs seem to be hit the most/fastest with 5 speed transmission failures, as well as axle failures. Road racers see it less often.

The last point to make is that you can't go by the dipstick for fluid level because the transmission is at a different angle. If you go by the dipstick, you will have way less oil in there than you need. Fill the transmission with the amount of fluid the factory says it should have then cut a new notch on the dipstick at that point for future reference.

[Pearldrummer7]

My ring and pinion on my (broken) 05 LGT trans is no stronger looking than on my (also broken) 07 WRX trans. Maybe they are different materials but everything looks the same (size of teeth, color etc.)

[Hindsight]

I've been a staunch 5-speed advocate due to not wanting to have to row through so many gears on a light car with a lot of power, but after having been to the track, I've decided to change my mind. When my 5 speed blows, I'm probably going to get a six speed. More durable, and the extra gears really help on the track.

[The Race Line]

If you want to add some strength to the ring and pinion your best option would be to have the new set cryogenically treated. This will stress relief the metal and make it far stronger. In terms of the differential, there are several to choose from. I would be happy to help you with that.

Let me know how I can help,

Erik Johnson
The Race Line
(720) 899-6005 phone