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Finished putting my AWD gearbox into the RX last night. Went for a drive, and 1st gear whines like its straight cut (the same as reverse gear whine). The noise only comes on at about 2,000rpm which is similar to reverse gear aswell...

Now i had the gearbox apart and was checking all of the bearings for noise - all of them were in excellent condition! If anything the front diff and centre diff bearings were a little noisy, but still acceptable. I even checked every gear for noise aswell. The only thing i didnt check was the synchros - cause i didnt know how, nor have a workshop manual for the clearances. Also, the gearbox hasnt been run for over a year... Yet everything still had a layer of oil on it when i had it apart.

Does anyone have any ideas or suggestions to fix this? Could it be that the gearbox hasnt been run in enough to get the oil circulating to something? Or could it just be a worn synchro and nothing of an immediate problem?

What sort it quick fixes could i do for it? Put in some thicker oil to stick to the bearings better? or thinner oil to get to the bearings easier? Or some kind of friction modifying additive?

edit: although it is a very cool noise, i am selling this car asap so i cant really keep the noise Otherwise i would!

Cheers!!!
-Adam

my awd box has the same noise, it has always had it and it doesnt get any worse so i havnt worried about it
jeff

ive actually just gone and checked the oil level and its only on the very tip of the dipstick... When i first filled it up (before running) it was perfectly on full (to my amazement of ability ). So i'll have to throw some more oil into it and see how that goes. Might have just needed to be filled. run/driven for a bit, then topped up once it finds its way through the box i suppose.

Might explain how sometimes its quieter all of a sudden - probably from sitting on an incline and 1st gear getting a little more oil.

Though what you've said Jeff is interesting. So is it just first gear that whines like reverse? I think mine has a VEERY quiet whine in 2nd gear aswell sometimes... dunno.

Cheers!
-Adam

If it helps at all my very unhealthy L series 5 speed non-AWD Dual range whines in 1st and 2nd but 2nd is much quieter.

It had about 140,000 Km's on it when I got it but the last 1,000 or so we're a severe thrashing by the son of the wrecker (I found this out afterwards).

It's done it the whole time I've had it, hasn't got any better or worse, but the syncro's are in a pretty bad state.

I found 500mL (recommended amount avvording to the tube) of the Nulon gearbox additive quietened it heaps and made gear changes a bit smoother.

Don't know if this helps but good luck with it.

Jordan.

Yeah that Nulon stuff is good i use that stuff myself.

Dave

ok more of an update - for anyone out there who might have been listening

Checked the gearbox oil level again and it was actually on full... So when i said it was low earlier - must have been a bad reading. With that in mind, i drove off to the shops and bought 2 tubes of that nulon N70 stuff. added that in - oil level is now slightly high. Have done about 50-100kms since, 1st gear is still noisy - possibly a bit quieter, but not a lot. And since then i've also noticed a grinding/whirring noise but only when on throttle, even if only gently... And gearshifts still feel quite stiff and notchy...

So in conclusion, im not sure if either my gearbox is shagged. or if the nulon additive doesnt work, or if it just takes longer to work/mix its way into the oil...

Cheers
-Adam

It was pretty well instant for me, I would say a 50% reduction in noise and 50% easier gear changes.

Jordan.

hmmmmm.

Though i do remember reading on the tube it said one tube (125ml) per 2L gear oil... our gearboxes are 3.3L or close to that... so i put in 2 tubes (250ml).. as opposed to your 500ml, unless that was a differrent product - or one of us read it wrong.

Now that you mention it 250mL sounds right.

It was a couple of years ago now so it's a little foggy.

Jordan.