Gearbox Rant

[unkn0wn]

Nice work! Keep up the updates.

Will do, cheers.

Thats one way to fix it, I dont know if i would of been game enough to do what you,ve done. But it seems ok looking at it, desperate times call for desperate measures

I thought about it all day @ work. I could have left it, but im sure there is a good reason why there is so many bolts...so i decided i wanted some method of applying holding tourque in that area.

I dont have another td27 bellhousing, i do have a ka24 one, but they are different. I checked its thickness and decided i would be ok to proceed.


from another gearbox thread : http://www.navara.asia/showthread.php?t=14208

http://www.youtube.com/watch?v=kxkOKb6R3mM

I feel sorry for this guy, as I did the same thing, ignore the whining noises and all of a sudden I had 2 smashed bearings and a cog missing teeth...not a nice way to go..

 

[unkn0wn]

ok so everything is back in and together

car runs fine

gearbox makes a hell of a whining noise on de-accel, coasting.

my guess is the front bearings are spining / incorect size.

can anyone identify this noise?


[YT]http://www.youtube.com/watch?v=CbNm-TEpwh4&feature=g-upl[/YT]

cheers,

 

[Dion]

Only happening on decel indicates a thrust issue, did you skip a thrust washer or a spacer or something? Could be a spinning bearing that under loading is somehow wedged and retained, but under reverse loading is spun. I like the thrust theory better though.

 

[Old.Tony]

I've not heard a gearbox do that before but it really sounds like metal-on-metal. There are hints of this 'scraping' sound during acceleration too - it's nowhere near as pronounced and somewhat masked by the diesel engine sound, but seems to be as you're backing off the throttle a little. Have a listen at around 26sec into the vid, you'll hear it for a fraction of a second there.

When you're accelerating the engine is imparting the force on the gearbox, putting the drive train into tension which is going to force the components to move one way or the other. When you back off or coast, those forces change, so that it's now the gearbox that is pushing the engine.

I like Dion's theory.

 

[Dion]

Does it happen in all gears or only 1st, 2nd, 3rd and 5th?

 

[unkn0wn]

Only happening on decel indicates a thrust issue, did you skip a thrust washer or a spacer or something? Could be a spinning bearing that under loading is somehow wedged and retained, but under reverse loading is spun. I like the thrust theory better though.

now that im looking over the manual, i do know i havent installed one washer...
i will look thro my bits again, but i could swear when pulling it apart i ddient have on of these on both boxes....Might need to have a better look tho....

would this cause the issue?

i do have the snap ring installed

and i do have the highlighted green shim installed

Does it happen in all gears or only 1st, 2nd, 3rd and 5th?

although it hard to nice in 1st, it will occur in all gears.

when installing the camera, i noticed it makes the noise on idle (faintly)
it just hard to hear over the clunky diesel
but i pushed back the clutch fork boot and the noise got louder, so its definably emitting from somewhere in the bell-housing area.

i manoeuvred the thrust bearing off the clutch plate, to see if it was noisy.
the noise did not stop (as expected as i have a brand new Nissan thrust bearing in there ~$80)

from : http://www.navara.asia/showthread.php?t=14208

Have found the problem, pulled the box out as the noise was getting worse in all gears from 2900rpm on and had developed into a screech type of sound.
It was the input shaft bearing spinning in the housing as the alloy support wall between the bell housing and box is too narrow to hold the bearing properly resulting in bearing spin after the bearing started to get a bit worn. I will renew all bearings in the box as the kit was only $265.50 plus gst, this time the bearings will go in with Loctite 638,
Found this on utube probably started the same way http://www.youtube.com/watch?v=kxkOKb6R3mM
Cheers

 

[Dion]

Well happening in all gears doesn't narrow it down to the layshaft, but I'd be looking at everything that is influenced by the thrust from helical gears, especially on coast. If it's there albeit quietly in neutral then focus your attention on the input shaft and layshaft.