Forums/Z31P/z31-repairs-forums driveline/Whining Gearbox
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Big Supes: (2016-08-23 22:00:41)
I think it's the thrust bearing. Its noisy as hell. It quietens down when you get into 4th and it also disappears when you engage the clutch when in neutral.
Just wondering what peoples thoughts are going forward? I'm aiming for 450bhp. Is the standard box ok for that power? In other words, is it worth having it pulled apart and serviced?
mtherkamp: (2016-08-24 10:58:58)
Transmission input bearing. Mine does it as well, waiting till I HAVE to rebuild it to fix. If you are truly wanting that much power, I would at least pull the the trans to check the condition of the clutch. Probably go ahead and upgrade that and resurface flywheel. At that point if the trans is already out, I would go ahead and rebuild with fresh syncros, since the stock ones are typically worn or damaged by using GL5 instead of GL4 gear oil.
Gem84Znt: (2016-08-24 11:47:20)
I have a 71C that has been doing exactly the same thing for several years. At first I thought it was the input shaft bearing, then I checked for the sound with a stethoscope and the noise is coming from the rear of the transmission not the front. I have done nothing about it because the transmission is operating as it should, plus I have no idea what to do. Also my car is near bone stock.
Big Supes: (2016-08-24 20:09:20)
Interesting… I guess I'll have to investigate the noise to see where it's coming from. Is the stock 5sp ok for 450bhp?
Gem84Znt: (2016-08-24 22:04:23)
If I were to go for high horsepower I would use the 30A transmission. Now back to the whine in the gearbox. If were the input bearing why don't our transmissions whine in fourth gear. also you haven't said which five speed you have.
Big Supes: (2016-08-24 22:09:27)
If I were to go for high horsepower I would use the 30A transmission. Now back to the whine in the gearbox. If were the input bearing why don't our transmissions whine in fourth gear. also you haven't said which five speed you have.
Being honest, I have no idea which 5sp is in my car. All I know is my car is a UK specification 2+2.
mtherkamp: (2016-08-25 12:22:08)
Mine is a 30a and whines in all gears. I suspect that there are different failure modes that cause the whining, or that the driveline harmonics in particular cars may mask or mitigate the whine at various speeds or loads. I have not taken mine apart to verify which bearing is failing, just going from other people's experience. Regardless of which bearing is causing the issue, the trans has to come out to figure it out and probably be best to give it a refresh while its out.
kaur: (2016-08-30 05:09:19)
Being honest, I have no idea which 5sp is in my car. All I know is my car is a UK specification 2+2.
It has a 30A if it's an 87+ stock turbo.
Big Supes: (2016-08-30 12:41:43)
It has a 30A if it's an 87+ stock turbo.
Thanks for confirming mate. Silly question, but do you know the correct engine code for my car?
kaur: (2016-08-30 17:00:59)
Thanks for confirming mate. Silly question, but do you know the correct engine code for my car?
Sorry, not really. I would try digging into the FSM for any info on that.
Big Supes: (2016-08-30 17:05:30)
No probs… I'll take a look at the weekend.
midian: (2016-08-30 18:55:11)
Thanks for confirming mate. Silly question, but do you know the correct engine code for my car?
vg30et factory turbo
vg30e - factory na
which codes are you talking about? O_o
Big Supes: (2016-08-30 19:05:31)
vg30et factory turbo
vg30e - factory na
which codes are you talking about? O_o
Ah ha, thanks Midian. It's a factory turbo, but didn't know if it was different for the UK. Mine must be the vg30et.
So, what car is the vg33et in? Is this like a stroker kit or something?
88sinZ: (2016-08-30 20:42:51)
Open the hood and look on your strut tower. There's a metal plate about the size of a playing card that has the VIN, engine code, transmission model, and differential info (differential info that was misprinted on some late 87's and 88's) among other info. Not sure about UK models but US models had it on the left fwd strut tower.
The 3.3's have a larger bore, stroke is exactly the same.
Big Supes: (2016-08-30 21:02:48)
Awesome, thanks 88. I'll have a check. Do you know if there is a lot of difference in terms of tuning potential between the vg30 and the vg33?
88sinZ: (2016-08-31 05:13:39)
larger displacement = higher power output.
The 3.3 was basically a further development of the 3.0 - while still not *great* to modern standars.. it was an improvement. State side they're common enough in junkyards it's a waste of time keeping a 3.0.
Reference: https://z31performance.com/forum/z31…rmation-thread
Long story short, break a 3.3 down to a rotating assembly with heads and slap all the other BS onto it and drop it in.
Big Supes: (2016-08-31 05:47:04)
That's not good to hear. I may end up going down the RB20 route as there are so many here in the UK.
88sinZ: (2016-08-31 06:42:20)
At that route, i'd still say displacement is your friend - go RB26/30 with a large single turbo. Maybe consider shipping some of those RB Z31 crossmembers to the US to fund your work!
The RB mounting locations should be the same bolt in affair, so go big.
Big Supes: (2016-08-31 07:07:58)
RB26 would be worth it just for the noise alone. [archived image: smile.png] When I get the time I'll work out some cost comparisons on the options.
Big Supes: (2016-09-06 18:39:58)
Guys, I can get hold of a Z32 gearbox, but it's a pre-1998 box. As mine is whining like hell, do you think this would be worth swopping in? I've been told it can handle 700bhp/700lbs.
Will it be compatible with my flywheel and prop shaft?
midian: (2016-09-08 05:54:58)
get at least 600whp, after think about other gearbox.
Big Supes: (2016-09-08 07:02:17)
I think I'm going to swap it anyway due to the nature of this thread.
Ski300zx: (2017-01-26 10:30:45)
if you have a 30 a trans, the z32 trans guts are the same, but the extension housing/shifter is different. not sure, but you should be able to open it up, take the gear and shaft assembly, and put your bellhousing and extension housing on it. I did this with a 71c out of a 240 and used my bellhousing and extension housing.
Timbo_021: (2017-01-26 23:11:25)
I don't think you'll be able to put the extension housing on because the output shaft is shorter. But bellhousing will work and make things a bit easier. As for the whine, it's probably main shaft bearings. Try changing the oil and see if it helps at all. It's nothing to worry about until it starts sounding like a super charger [archived image: tongue.png].