Gearbox/diff squeak, poor engine braking

[Kiz]

Hey guys, first post :)

I have an intermittent squeak, kind of like a belt squeak but coming from the gearbox/diff area. It only happens when the gearbox is warmed up. Its very noticeable when you turn the car off and everything slows down for that half second.
I changed the gearbox fluid to Royal Purple 75W-90 2 months ago.
I've tried clutch in/out when I can hear it squeaking (usually at Maccas drive through when the sound reflects off the wall) Clutch does nothing but change the engine revs ever so slightly which in turn changes the frequency that it squeaks (which is already very irregular, not a cyclic noise).
Gearbox fluid level is perfect, well it was when I filled it a month ago and the car doesn't leak a drop of anything.

I've done the screwdriver to the ear test tonight on the AC, alt and driveshaft but since the hearbox wasn't warm when I did it I couldn't hear anything from them.

I've noticed it does have more 'crackle' in the engine than usual (kinda like intense pinging but it's always done it) but only slightly more, couldn't tell if it started with the squeak.

I did fit a lightened UD pully in 07....

Today I noticed that there's no resistance when engine braking. Well OK there's a little bit but I attribute that mostly to rolling resistance. 2nd gear does provide better engine braking but 3rd and 4th it's like the car is in neutral. Acceleration is OK, I heard one loud squeak around 2000RPM in 2nd gear while accelerating mildly but it never occurred again.

I also swore I had a flat tyre today - uneven braking, vibration and mushyness... stuck my head out the window at the lights and they were fine! Couple of minutes later and it was back to normal. Maybe I'm going crazy


Don't think there's anything more info I can think of right now.
Oh it's an '06 LB 2NZ-FE 5-speed.

I've had spigot and GB bearings suggested as causes. Eliminated the throwout bearing as the clutch makes no difference to the squeak.

Thanks for reading, hope you can help :w00t:

[1NZYaris1]

Sounds like your accessorie belt , not the gearbox :confused:
how many miles on the car.

[Kiz]

35000km ~ 22000mi. Have confirmed it's not accessory belt. The noise is definitely coming from the gearbox area. It's not like 'squeak,squeak,squeak,squeak', more like '..............squeaksqueak.......squeak.......... ......squeak.......squeaksqueaksqueak.........sque ak.....' no regular pattern about it.

[Lafiro]

I have the exact same problem as you described. Try getting next to a wall with the car in reverse or drive, right after a drive, and I hear it all the time. Its an annoying sqeak that does not appear to be originating from the accessory belt either.

The major difference between you and me, you are manual, I have the automatic. But the sounds and every detail of what you said I am experiencing.

So if you find a fix for this please let me know as my dealership just said the old saying "we couldnt reproduce it".

[Kiz]

Aaah well that would seemingly elimiminate the GB and throwout bearing for sure then. Good to know I'm not the only one, bad because we still don't know what it is!

How long has yours been doing it? Hopefully it's not a potentially fatal problem and I can live with it til I get my Z back on the road.

I have the exact same problem as you described. Try getting next to a wall with the car in reverse or drive, right after a drive, and I hear it all the time. Its an annoying sqeak that does not appear to be originating from the accessory belt either.

The major difference between you and me, you are manual, I have the automatic. But the sounds and every detail of what you said I am experiencing.

So if you find a fix for this please let me know as my dealership just said the old saying "we couldnt reproduce it".

[Lafiro]

Probably close to a year now? I only rmember it happening as of late, nothing past a year. I will try to record this later. Tried it last night but the sound of the airplace going by messed it up, and I did not want to keep filling the garage with CO.

[Kiz]

I took a recording when I got home after first hearing it... problem is the engine noise drowns it out. I canhear it, but I know what I'm listening for. It's most audible at the end when I turn it off.

http://www.youtube.com/watch?v=Y5zwju0qxUM

[Kiz]

I had a thorough inspection today of the pulleys and belt. Nothing out of the oridinary, no squeaks when I turn them individually. I did tighten the belt a bit more than it was originally (alternator position determines belt tension), about centimetre more on tha alternator bracket. As well as that I drained the gearbox to the correct level as I filled it with a car on an angle last time. Couldn't have been more than 50mL extra in there.

Took it for a drive and again nothin when cold, but once warm the squeak was back and much less irregular. It's still on...off, but when it speaks it will do so for several seconds at a time. Drove for 40 minutes and by the time I got home and back under the car to check there was no more squeak! ANNOYING.... oh well... Will let you know if it doesn't come back I guess.

[Lafiro]

It will be there.

Lately I haven't heard it either, but I especially heard it last night putting the car into the garage, and turning it off sounded like it was dying to a halt.