My trans failure

[nimblestix]

So recently I posted about blowing third gear at the track.

Just wanted to leave these here for your viewing pleasure.
I originally bought a used trans that was supposed to be good, so assuming it was fine i installed it and before testing it I wanted to change the fluid, so I pulled the plug and this is what I found:


I've now replaced this trans with an apparent working one, although I haven't road tested it yet, on the jack stands at 100kms it seems quiet.
Thanks again to the members that helped me out massively, you know who you are.

This was the trans that I blew third gear out of when racing at mission raceway.




Awesome!

I think I'm good to go again. That was a long week of beautiful weather and no GTR, and now it rains. Bah.

Cheers!

[bobbo]

Well done! That's some nice carnage!
Out of curiosity how much power are you making and are you running slicks?
I'm interested in the likelihood of having a similar issue at the drag strip.

[Dragon Humper]

I'm pretty sure he was on street tires. Slicks would be much better. They take a lot of shock and harshness out of the equation. Kindof like riding on big marshmellows. The hook and release is much smoother on slicks as well, more progressive. Street tires are pretty violent, drag radials are better but can still be harsh and slicks are the most forgiving.


'cept you float and wander all over the track. You should practice driving at speed with them before you go to the track, especially if you are going to use them front and back.




Jon.

[nimblestix]

Street tires, and I'm making around 500 whp (dynojet)

The best part is when I shifted into third it instantly blew, I panicked and tapped the brakes then coasted the rest of the track (about 1/2 way) and I still cleared a mid 15 second run! Haha, I think I was gunning for my fasted time that run.

Sent from a galaxy far, far, away.

[bobbo]

That's some big power. I won't be there with my car but close.

[Black BNR32]

neat pics.
why is the fluid so milky?

[nimblestix]

That's redline heavy shockproof. It's funny my dad keeps going on about how milky it is, I'm assuming that's how this fluid looks regularly though as I also had it in my front diff and it too is milky.

[Dragon Humper]

Street tires, and I'm making around 500 whp (dynojet)

The best part is when I shifted into third it instantly blew, I panicked and tapped the brakes then coasted the rest of the track (about 1/2 way) and I still cleared a mid 15 second run! Haha, I think I was gunning for my fasted time that run.

Sent from a galaxy far, far, away.

Lol....last time I was at the track I didn't have a helmet so I promised that I wouldn't go under 15 sec. On one run I took it a little too far and ran a 14.80 at 37 mph. Can you tell I was standing on the brakes as I crossed the line. I'm going to try and run a low 10 or high 9 this year with a stock tranny. Yes, I am on the lookout for a cheap replacement near me if it pops.


Jon.

[NismoS-tune]

Got a spare r33 for Grabs unless $1000 is also too rich a gearbox for a low 10 second car.P

[Terrh]

when did these transmissions start going for a grand? I've never paid more than $200 for one yet.


I am starting to wonder if shockproof heavy is killing transmissions. I'm not running it in mine anymore and I haven't broken any gears since I stopped.

[Skym]

With gearbox it has clearances inbetween gears and thicker oil than what it was designed for at operating temp can close those clearances thus put more stress, drag on gears, which is then transfered to bearings that wrap around the shafts, synchro's, etc.

Stock gearbox is only designed for around 10-20% above factory engine torque levels. Higher torque levels than design limit = shortened lifespan of 3rd gear. I know Nismo have testing data to back this up for SR20DET gearbox 3rd gear which uses similar internals to RB20DET gearbox (different housings, etc) and is rated to a certain amount above factory torque level with SR20DET gearbox before lifespan of 3rd gear is reduced dramatically. The fix is thicker gears (what is shown with Nismo upgraded internals for SR20DET gearbox, and is shown with upgraded internals for R32GTR gearbox from PPG), upgraded bearings (I noticed there are race spec bearings available for R34 GTR Getrag gearbox).

[NismoS-tune]

Who knows. I paid $1200 for it last year from a member on here (no need for names eh) then instead went PPG dogbox.

R32 box costing around a carton of smokes? Ok but r33 too? I see them for all sorts of prices. Tack on shipping from out of country and bam! uplift in price.

when did these transmissions start going for a grand? I've never paid more than $200 for one yet.


I am starting to wonder if shockproof heavy is killing transmissions. I'm not running it in mine anymore and I haven't broken any gears since I stopped.

[Dragon Humper]

After seeing exactly where 3rd gear is on the cluster in the above pic I am convinced it has more to do with driver error than anything else. If any gear should be blowing it should be 2nd. Why?

If you look at the pic you will see that 2nd and 3rd are equal distances from the brgs in the bulkheads. But 2nd gear has more leverage on the driven side of the cluster than 3rd would (the clusters are trying to push each other apart). You never hear of anyone blowing 2nd, always 3rd. I have pushed all the motor is worth through 3rd and have yet to blow it (830 gross HP). I have heard of people blowing 3rd with HALF the HP I am running. Do I have a freak trans that is tough like Rocky Balboa? Doubt it. I am just very deliberate and carefull shifting into 3rd so as to not get caught between gates and I NEVER let out that clutch unless the shifter is firmly planted at the end of the travel into 3rd. It costs me time in the Quarter but that's OK, 4 summers and no signs of destruction yet *knock on wood*.





Jon.

[nimblestix]

yes you are correct Jon, this damage was completely my error, I was shifting far too aggressive on this run going for that low 11' second pass!

I was holding pressure on the stick while in second and as soon as redline came, I slammed her into third with a split second clutch kick. It was an equation for failure! Just sharing the carnage lol

[Dragon Humper]

My time may come yet. Those loony Brits have it all wrong, most people are right handed and it is much easier to really bang gears with the right hand than the left. I play guitar so my theory is that all that finite work fretting with the left hand helps me work the stick a little better than most (boy that really comes out dirty doesn't it....lol). With my Camaro I could bang gears with the correct hand so well that most people at the strip just assumed that my car was an automatic (I would leave at only 2500 rpm and slip the clutch out of the hole to make the most out of street rubber).

On the Shock Proof Heavy subject, I find that the gears fall into place with more of a distinct notch, telling me that the syncros are making more of an effort to get the gear speeds the same as it goes in. My crunching into 4th is gone and the whole thing feels less sloppy through the shifter. On a new trans the Heavy might not be a good idea straight up but on an older box, I think its just the ticket (so far anyway).




Jon.