Hi,

 

OK, I’m getting a crunch when changing down from 5th to 4th , this only started a couple of days ago.

 

It’s on the motorway and after being in 5th for a bit (particularly after being under load) if I try to gear down it crunches, I’ve tried other gears straight from 5th (obviously going slow enough to use them) but it’s the same thing.

I’m assuming it’s the selectors and that they aren’t quite working correctly.

I’ve booked it in to have the gearbox oil checked and toped up (possibly with MT-90).

 

Has anyone else had the same issue?

 

My search found a few other “crunch” problems but nothing exactly the same as mine.

 

Cheers.

Syncro problem. Quite common. Try gear oil change but you can also double clutch to stop it

Ta... :)

 

however double clutching didn't seem to do any good.... even pumped it a few times.. no difference.. (I should have mentioned that...lol... getting old)

Could it be clutch is worn enough to still engage lightly and prevent complete disengagement ? If you are double declutching you should, in theory, not need the sychros because of your spinning up the box to the rev speed of the selected gear

Ah, yes, but why would it only happen on the motor way and in 5th?

As said its likely to be a syncro problem - there is a syncro ring on each gear & their job is to syncronise the speed of the gear to the shaft so as you engage the next gear the selection is smooth. When they are worn this stops happening hence the crunch in any particular gear.

 

A decent oil like redline or manual gearbox additives can help reduce the problem but if they are worn then it is likely to be a temporary measure.

 

Probably worth a go however! :)

Hi,

 

OK, I’m getting a crunch when changing down from 5th to 4th , this only started a couple of days ago.

 

It’s on the motorway and after being in 5th for a bit (particularly after being under load) if I try to gear down it crunches, I’ve tried other gears straight from 5th (obviously going slow enough to use them) but it’s the same thing.

I’m assuming it’s the selectors and that they aren’t quite working correctly.

I’ve booked it in to have the gearbox oil checked and toped up (possibly with MT-90).

 

Has anyone else had the same issue?

 

My search found a few other “crunch” problems but nothing exactly the same as mine.

 

Cheers.

This is a common zed complaint and relates to a failure on 4th gear syncro,nissan were aware of this weakness and devised an uprated syncro,baulk ring,dog and fork to repair it.Its not cheap though.Over £400 for those parts alone.Oil level etc will not cure it.

This is a common zed complaint and relates to a failure on 4th gear syncro,nissan were aware of this weakness and devised an uprated syncro,baulk ring,dog and fork to repair it.Its not cheap though.Over £400 for those parts alone.Oil level etc will not cure it.

 

ouch, and how much to fit it??

 

would just changing the oil often help this? (before the problem) as i have never changed the oil in mine since having it.

ouch, and how much to fit it??

 

would just changing the oil often help this? (before the problem) as i have never changed the oil in mine since having it.

 

Oil changes wont help,the fault is the syncro is not beefy enough to handle the torque the engine produces at the higher engine speeds.Syncros are brakes basically that slow gears down to engage the sliding dog,this is why oil doesnt help as the cone and baulk ring are designed to disperse oil to help shifting.