Hi,

Got a tricky problem with my FD... its a '94 Type R, on stock twins, running a possibly lightly ported engine... manual gearbox. (~300fwhp)

Basically, the problem is I'm getting a horrible grinding noise coming from the transmission tunnel...

When the noise first started, it was quite quiet, only happened when the engine was under load and only in 2nd and 4th gear. Now its getting louder, happens even when 'engine breaking' and is spreading to the other gears.

It only started happened after having the gearbox rebuilt, so I assumed it was that.... it has since been rebuild a second time (with no wear noticed internally) and put back in (single bearing changed for the heck of it!)... noise still there.
A different (known good) gearbox was fitted from a different car, and noise still there... now gone back to original gearbox.... noise still there.

When the gearbox was originally rebuilt, it also had a brand new clutch put it in (Exedy Single Plate Organic)... used to have an OS Giken twin Plate (push pull type).

Pulley belts were removed to check for odd engine vibrations / noise, but nothing.

Any idea what else in the drive train might be causing this grinding noise... it REALLY sounds like metal on metal / bad bearings / gears meshing. All bearsing in the gearbox and gears themselves inspected and found to be fine. Diff is also recently replaced with known good low mileage stock item.


Pleeease help


MORE INFO ON CAR:
Its got a big FEED intercooler, stock twin oil coolers, Apexi 8bit Power FC (no commander)... It was mapped by a very good UK mapper when it came over, to a nice and safe 300fwhp.

A bit of history...
Car was imported into UK from Japan in 2006, having had an engine rebuild and map by FEED in Japan.
It had about 5,000Kms on the new engine, and has now done an additional ~10,000Kms.
(total of about 60,000MILES in total on odometer, though the chassis, electrics and shell are about the only original things on the car right now!)

It looked and drove fine when I bought it, but I've since had to get a lot of repair work done on various bits cos I think it had been thrashed in Japan...
I have :
Replaced old 1.5way Kazz diff with stock Mazda diff (low mileage)
New clutch (Exedy Organic single plate)
Rebuilt gearbox
New Tein Super Street coilovers
Replaced turbo pack (stock)
Got a FEED downpipe, stock cat, large back box.
Solid engine mounts

 

bump...

no one?

 

I dont know if it will help but i had the same problem and it was a rear trans berring. but i have a 85 gsl.

 

have you checked the driveshaft? Could be bad u-joints

 

+1

My FC had a similar noise...greased front u joint, no more noise.

 

check the uni's, most likely
check the oil slinger cover for the slip joint on the tailshaft is on intact
- they can crack the spot welds and then ride on the gearbox extension housing
that makes for a hell of din !

 

ok thanks... will check those... and report back

 

Turns out the grinding noise was being caused by the main needle bearing in front of the main shaft... it sounded louder in 2nd and 4th because the protective boot above the gearbox that leads to the gearstick had split... pulling it into 2nd and 4th opened the split more so it sounded louder...

you live and learn!