Grinding/Vibrating driveshaft/gearbox + Lift help !!

[dandownunder]

Hey guys,
Well I am confudled now. I installed some 4" springs in the rear of our Surf a month or so ago to level it out with my front balljoint lift.
I now have a vibration around the gearbox area when revving fairly high (3000rpm) and going above 80kmh, more noticable around 100-110kmh when on the freeway.
When on the freeway and you back off the accelerator the vibrationg then becomes a grinding sound . This only happens on the freeway, as I have only just noticed it when we drove to Fraser Island.
This has only happened since the new springs/shocks went in. There is nothing hitting anything, my uni joints are fine so would anyone know what it might be ?

Do the people that have superlift kits have an adaptor or anything on the rear drive shaft to help with the lift ? it is a fairly big angle for the drive shaft (compared to stock).
Would appreciate any information anyone has to help track it down. It's at Rays now having CV boots done and a grease up so he may find something aswell.

At the same time as doing the lift I also drained and flushed the gearbox and added new gear oil. It is deffinetly coming from rear of the gearbox/towards the diff.

Cheers
Dan.

[roberts]

if it only does it in 5th the your gear box might be on the way out

I had the same symptons in my hilux for a while then 5th and reverse snaped off the cluster shaft

might be the same thing in your surf

[dandownunder]

It does it mostly in 5th, but i probably notice this because it's the only time I can get to 100/110kmh. It does vibrate in other gears but more so in 5th ???? and makes a grinding noise in 5th.

I don't have any problems with clutch/gearbox that i know of, and it only happened once I put the bigger lift in so it must be a driveshaft issue/diff issue ??

Cheers
Dan.

[alrob]

i had similar problem. rear diff was on way out. ended nasty, with 5 broken teeth.

the pinion gear, not mine!

[alrob]

now for a reply that may actually help.

i knew mine was farkd, because i could grabv the flange at the diff, and move it sideways, and up and down ,and all around. HEAPS of play. thats what was doing it for me. the bearings had shat emselves

[dandownunder]

Cheers guys.

There is no play in any of the uni's or around them (diff etc) so really am lost as to waht to do. A few people I have spoken to have had double joints put in at the gearbox end, and others that have had the superlift additions put on theirs, so really not sure what to do

It's just crap to drive on the motorway !! It used to be great and that was 2" spring and 1" spacer on the spring so 3", amazing how 4" can throw it off.
Cheers
Dan.

[Jimbo]

Did you keep your old springs??? You might have to put them back in and see if te noise goes away. I had my rear uni replaced 2 weeks ago. It was making a bad noise around 60km/h. It felt like there was no free play but it was kinda seized. But when i tried to undo the uni with a spanner it clicked free and there was heaps of play!! Got it fixed and all the vibrations and noise went away

[Suspension Stuff]

Your tail shaft uni joints should be parallel (to be in phase). Maybe it is no longer parallel because of your lift. Don't know much about Surf's so could be wrong.