Rear end humming/vibrating hilux surf

[dandownunder]

Ok, heres a quiz, I'm at a loss here......I had a second hand diff put in the rear of the surf about 6 months ago to change my ratios, diff looked in great condition, no marks or wear. When Diff was in it worked a treat, no problems with it. A few months after having it in I installed a 4" rear spring lift, I then noticed a vibration in the rear aroun 90/100kmh, so had the longer springs taken out and put 3" lift back in, vibration went from 100kmh to 80kmh. Had the tailshaft uni's checked and were fine, tailshaft needed balancing. So after the balance it was a lot better but now there is a small vibration/humm around 80kmh is it safe to say that it is the rear diff and it may need an overhaul !????? only around 80kmh ?
Any info or anyone know what it may be ?
I just had the wheels balanced and aligned today and no improvement, even though the guy said the rear wheel was 200g out of weight !
Cheers
Dan.

[plowy]

any movement at the pinion ? excessive backlash ?

also a bad vibration from a tailshaft left for too long can effect the rest of the drive train

[dandownunder]

The surf was left to sit for about 4 weeks when I went overseas and the rear pinion started leaking when I got back, so it kind of started after that. ????

Thats why I am trying to sort the vibration, don't want it to bugger up the rest of the driveline.
Cheers
Dan.

[saint_she_aint]

Damn Dan, I dunno bout your problem, but when my rear diff went (twice and its on its way out again) it did vibrate a bit and made a loud whirring sound around 80 ks and then once getting to 100ks it stops.

Another time it vibrated without the whirring and turned out it was the uni, but u checked that already.

BLOODY SURFS!!!!

I think we both need to go to Jez's surf mechanics course

[sniper]

thats it....go and buy a 4Runner...

[4sum4]

Take the rear shaft of and see if the vibration goes away

[dandownunder]

Thanks for the input guys, Saint I am thinking it may be the diff in need of some help Will get Ray to check it out and see aswell

If you take the rear shaft off you won't get drive at all ? so then obviously you won't get the noise/vibration ? or is that to check that it's not in the gearbox ?

Cheers
Dan.

[sniper]

not a good idea to drive with out the rear powering the car. The front isnt strong enough to pull a hilux. Only should be done as an emergancy option, or you might have to rebuild 2 diffs dan

[sniper]

Also would of thought the vibration would come because of the tailshaft not the gears but you never now. When i done my rear diff it just whyned (like a woman after money) never shook the car. I smashed my crown and pinion to pieces but it never vibrated.
Hope it all works out for you

[saint_she_aint]

yeah ur right snipe, mine didnt vibrate when i did the diff each time, just the uni.

it just whined like a man after sex

[dandownunder]

we don't whine !

I am wondering if it's the gearbox now ? my syncro seems to be playing up....hmmmm I'll get Ray to have a look and then see from there.

Don't worry Sniper, wouldn't drive it with just the front locked in and no back, doubt it would do it much good.
Cheers for the info guys
Dan.

[mud guts]

i dont know if you have leaf springs or not, but i had a similar prob with mine. The locating bolt that holds the center of leaf pack together had snapped alowing the diff to move therfore changing pinion angle, incidently both sides were snapped , after fixing no vibrations.

[dandownunder]

Nope, I have coils in the rear of mine. The pinion angle was a lot more when I had 4" lift in the rear and taking the big springs out and putting 3" in there has brought it on, so am thinking it may be a side effect of this ??

[NiftyNev]

The Surf site is very quiet so I thought I'd have a look here. Now I know why. You are all here.

Nev

[dandownunder]

aah you found us Nev Just trying to get some more info on this problem, thats why i posted here, wondered if any other hilux's had had it ?

Cheers
Dan.

[saint_she_aint]

haha we were just trying to get away from the pesky mods.....oh hell I forgot ur both mods!