Whining noise when backing off accelerator

[fabezzz]

Ive just noticed this funny noise when in second gear. It only happens when i back off the accelerator completely at about 4kish rpm instead of shifting to 3rd and just let the car roll on its own.

Could it be the CV is on the way out or is it nothing major.

[trism]

sounds like could be a syncro?mine does the same in 1st 2nd and 3rd

[burak213]

i get a whining noise accelerating...

no idea what it can be

[JohnL]

In a particular gear, whining is likely to be wear on the teeth of that gear. If in all gears then it could be a bearing, or maybe teeth wear in the differential.

Since synchro rings are doing nothing except when shifting gear, I can't see it being the synchos (I can't even see the synchros causing a whining noise when changing gear).

I wouldn't be too concerned if the noise is slight, and unless it starts getting worse. However, I would be checking my gearbox fluid level right away.

[OMG.JAI xD]

^^^
2nd that.

[fabezzz]

It does it slightly in 3rd gear aswell how much would i be looking at for a new bearing?

[Bludger]

It does it slightly in 3rd gear aswell how much would i be looking at for a new bearing?you don't even know for sure if its a bearing noise..

get a proper diagnosis from the right technician.

[fabezzz]

you don't even know for sure if its a bearing noise..

get a proper diagnosis from the right technician.

Yea its not that bad atm i just wanted to know how much it would cost if it turned out to be a bearing no harm in asking, i would check with a mech before buying anything anyway.

[JohnL]

It does it slightly in 3rd gear aswell how much would i be looking at for a new bearing?

Assuming it is a bearing (a big assumption at this point), how much $ depends on a whether the bearing is a common generic size made in millions of units (relatively cheap) or an obscure size made in only thousands of units and hard to source in any case (can be be outrageously expensive).

Whichever, the greatest cost would most probably be the labour cost in pulling the box out / apart and fitting the bearing. In reality the wrecking yard is very often a far more practical proposition than rebuilding.

FWIW, If I were in your shoes I'd just use the box as is, but, I'd switch to the best gearbox oil I could find in order to give the box it's best chance of lasting as long as possible. I'd be looking into a top quality synthetic gearbox oil such as Redline or Motul (among other brands).

If you use a synthetic gear oil, make sure it's compatable with synchromesh, and not a racing oil designed for 'crash' boxes (or the synchro may not work and the box might become a 'crash' box by default).