Gearbox loud knocking sound r33 GTR

[Tomak]

Gearbox loud knocking sound r33 GTR

Hello,

Have done about 4000km after gearbox rebuild and putting new Nismo clutch Coppermix twin plate, something broke again just today during slight acceleration on 4th gear. It was not even hard acceleration. My gearbox was fully rebuild on new bearing, synchros etc. Horrible loud knocking sound that goes away when clutch pedal depressed. You can hear this here. Dont know really what to do next with all this. This is devastating for me and will have to take my gearbox out again for the 6th time this year. ;/  What could possible went wrong this time?

 

Enybody experience something like this before?

 

 

[GTSBoy]

Why did you even run it for long enough to shoot that video?!!!??

Take it apart immediately.  It's f**ked.

[GH05T]

who built it? this is a very good question i would be asking them!

1 hour ago, Tomak said:

have to take my gearbox out again for the 6th time this year. ;/  What could possible went wrong this time?

 

 

[Steve85]

Volume warning for the end part of this video... 

Wow, that doesn't sound good. I don't think you are going to be able to fix that without pulling your gearbox. It definitely sounds as though something has gone wrong and is attempting to make its way back out of your gearbox case.

[Duncan]

well obviously it sounds horrible, but it could still be minor to fix like something loose on the pressure plate/clutch assembly.

assuming a shop did the reco and install I'd get it back to them....not that they would be around for the next few weeks.  other option is take the gearbox off yourself and see what you can find, but in that case you might have difficulty with warranty if it is major.  either way i'd call the shop tomorrow and see what they want before they close

[Tomak]

When this shit happened i was doing about 100km/h and the 4th gear dropped suddenly to neutral itself when i started to accelerate from stable driving. I know i should stoped imediately but its not easy to do when driving with loud exhaust and you dont know what is going on. Actually i put 4th gear back again and continue to drive about 2km so i was on the highway anyway and need to find parking space. Making this video wont make things worse i guess. Gearbox was actually 10 000km after rebuilding. Some shop done the rebuilding for me specializing in skyline gearboxes. Question is what type of bearings they used OEM or aftermarket. I think the bearing inside the gearbox got messed up like input shaft bearing or something. Is this possible? 

I wont get my answer for 2 weeks now because of holidays. My car is back in shop again. Next week i get gearbox fluid out to see if there are some iron fillings inside. 

Edited December 22, 2016 by Tomak

[BoostdR]

I've broken 13 gearbox's in my old GTR. familiar with that sound. Would put money on a gear or cluster shaft loosing a tooth.

[Tomak]

Wow, nice...its good to know ;/ My gearbox is old so i dont know if there is any sense to replace parts again and have a hope nothing breaks.

What other options do i have to fix that problem so i can drive my car without damaging the gearbox for at least two seasons?

I am considering buying now genuine new gearbox. Is it going to fix my problem or not with actual setup:

Car is pushing 500hp with Nismo Coppermix twin plate clutch with light flywheel.

I use this car for daily driving and occasional track days, 1-2 a year. I am not planning to do any 1/4 mile launches etc.

New gearbox cost around $3000, is it worth it or not? Does anybody has any experience with new gearboxes and how fast they breaks?

 

 

[GTSBoy]

New gearbags break at the same speed/power level that used ones do.  It's got less to do with the age of the bits....it's how fundamentally strong they are compared to the load you put on them.

[Tomak]

So far it look like every two races i need to fix the gearbox. I went one time for track pushing my car hard and this time just went for long trip for holidays about 3000km of constant driving on highway but not pushing my car very hard at all.;/ So the best option is to have another used gearbox in the garage for quick replacement and then fix the other one. But seriously i havent push my car hard yet at all. So if this gearbox breaks so easily what other options do i have? Is it possible to put different better gearbox for any reasonable money?

12 hours ago, BoostdR said:

I've broken 13 gearbox's in my old GTR. familiar with that sound. Would put money on a gear or cluster shaft loosing a tooth.

So why you not put different gearbox for example sequential quaife. I guess you are racing all the time if you breaks so many?? Its not worth the money or what is the problem?

[Duncan]

9 hours ago, Tomak said:

Car is pushing 500hp with Nismo Coppermix twin plate clutch with light flywheel.

I guess 400kw is heading towards the top of what the standard box will take, depending on driving style. I've been racing for with mine for over 10 years at 300kw, and have never broken a box, although I have reconditioned bearings and synchros a few times. But others with 400+ seem to strip gears often.

To be fair to the factory bits, you are making about 2.5x the power they were designed for....

Anyway, it looks like it's time to drop 10-20k on an upgraded box. Or keep putting in $800 second hand ones until you get sick of it.

[Steve85]

You could always rebuild it with OS gilken internals? Of course it will depend on what is broken and if there is any other damage.

[BoostdR]

I found they would break when changing gear too quickly. If you slow down the shift speed they seem to last considerably longer. I also went to redline lightweight shockproof gear oil. The smurf blood, and didn't break another box

[Tomak]

redline lightweight shockproof gear oil - this is interesting, thanks for the advice. 

10 hours ago, Steve85 said:

You could always rebuild it with OS gilken internals? Of course it will depend on what is broken and if there is any other damage.

I have seen this lately online....so anybody run this set up in the car? The price is not that horrible for something that will last for long time

http://www.neweraparts.com/Default.aspx?tabid=54&CategoryID=141&List=0&Level=a&productid=42

What do you think about that?

[Steve85]

I have it in my car. I am currently running more hp than it is recommended for the gearset though. From my very limited time in the car it seems to hold up well. That said i am careful not to rush the gearchanges and try to rev match where possible.

[Tomak]

How about the 6spd gerbox from r34 GTR? Does it have stronger internals or not?

[Sinista32]

^Yes stronger and smoother

although as said earlier its how you punish it that breaks them

Determine your future power level (load), how you will treat it and go from there.

i.e. "I smashed/rammed it into second and third" and that's what happens.

Cost several thousand up to $50k depending on what you intend on doing.

Over engineer and under utilise and it will last longer

[Tomak]

I just visited my mechanic today and my gearbox is totally f**ked, the 4th gear is messed up on both shafts, so i need the advice.

My actuall options:

1. Buy another used one, check it, and have a hope that nothing breaks. - 1000 USD. 

2. Wait a while around 2-3 months and build new one on Os Giken internals - around 3000-5000 USD and i dont have any shop in Poland who can do this for me with experience anyway. My mechanic can  build it, but first time in his life ;/ Would you risk that kind of money?

3. My mechanic said he can build another one on Nissan Patrol internals gearbox model FS5R50A which is more stronger and has thicker gears teeth. They actually build three of them in Skyline drift cars so have experience  in this modification already. Cost only 250 USD in this option and can have it in one week. I can use the rest of my unbroken parts from my Skyline gerbox, shafts and synchros.

The only problem are the gear rations ( The OEM Skyline ratios are  3.214 1.925 1.302 1.000 0.752 ) So it looks like only the 4th is the same. What do you think about this patrol ratios. Is it going to be less responsive and has less power at red line on 1,2 3 gear or what other problem can i have with longer gear ratios?...., less power or torque, problem with starting to drive from 1st gear etc...?

Patrol Gearbox ratios

1st 4.556  

2nd 2.625

3rd 1.519

4th 1.000

5th 0,836

rev 4.245

[GTSBoy]

The Patrol ratios are all shorter, not longer.  You will need to consider taller diff ratios.  If you're going to do that, then you should probably just do an R34 box.

[turboedsloth]

I'd like to see how he squeezes the FS5R50A gearset into your centre plate. They are a big setup

Unless he's thinking about the 2.8 patrol gearsets. Another thing to look at, 2008-2011 Navaras use the same gearbox, 90% of the part numbers match up to R34 units on fast