Gearbox or Diff issue?

[Drift_R32]

Drove to busselton on sunday in my auto VZ ss ute

i started noticing when i came to a complete stop there a slight clack/clunk when i went to take off again..
hard to exlpain but kind of like diff back lash but not

anyways drove back today hit the peak hour traffic and had to stop/start about 1500 times..
was clunking everytime even sometimes when it was dropping into first gear just as i came to a complete stop.

it got worse and louder so i gathered i better pull over, i was in the far right lane so i came across to the emergency lane
as i did this(my wheel was turned so one wheel was spinning slightly more/less however it works) it sounded much like a locker and clunked its way over..

had a look couldnt see anything

started it back up, did it once more pulled over again for 5 minutes..
thought fuck it ill try limp it home..

drove it all the way to balga from canning highway bridge without a problem..

jumped in it to check it against tonite and when in come to a stop and im holding the brake and its in gear, the revs are lower then they normally are and the car is pushing pretty hard on the brakes and kinda lurtching forward. hasnt done this before

Diff had the diff gears done under a year ago by the last owner..by Formula Tech (yes, i know probably the issue) but doesnt whine at all and hasnt clunked etc
Has a Harrop cover which holds alot of oil so youd think it would help.

gearbox has electronic shift kit, has done 115 xxxkm been serviced regulary and has a massive cooler
also shifts perfect when driving..

I had car on hoist on saturday before i left and checked backlash on diff and was minimal and all unis seem good ?

car is fucking low in the arse incase its an axle issue

soooo

is it the diff? or is it the gearbox?

cheers for any help!

[Brett_J]

Sounds like it might be dropping back to 1st too late, the lurching forward may be it still in second trying to drive the car still or not deciding what gear to be in.
Drive it like a manual and it does the same?
Reset ECU and try it again.
My brothers VZ SS ute POS has killed one auto in under 50,000k's and this one randomly loses top gear. Reset ecu and its good again for a few months.

[Drift_R32]

will give it a try tomorrow..

the 4L60Es are fucking piles of shit thats why it wouldnt surprise me if it was that
also wouldnt surprise me if it was Formula techs effort at installing the diff gears either.

[Brett_J]

You'd have to be missing teeth off the crown or pinion to be getting that much backlash :)

My torque convertor is fucked in my VR, some seal or bearing or something, basically has small vibration at take off, but when doing over 100km/h, it gets a tiny tiny vibration in the box and throws a code :)

[joshg123]

Id be leaning towards lock up torque converter clutch hanging on, if it was in 2nd it would just slip on the converter at revs and would still drop back to idle if 2nd gear clutch pack is on as there is no speed on the converter. Hard one to explain in writing

[Brett_J]

I admit I was just clutching at straws, not had much to do with them, have a 2 week course on them next year in feb so I can understand them better.

[Drift_R32]

Yeh I was thinking convertor from the way it was idling but wouldn't that mean when u take off it would be sluggish?

Seems to take off fine?

[stumps.]

Maybe change the diff oil, look up diff chatter on ls1.com.au and see if this is your issue.

Otherwise worn tailshaft doughnuts can cause this issue

[Drift_R32]

No worries.. Have had diff chatter before.
But don't think it's that.

Tailshaft is all ok looked on sat on hoist..

It's started something new.. When in gear with brake applied idling is really bad at 500rpm

[joshg123]

Not if it locks the torque converter and engages 1st gear clutch pack as normal, it would take off fine, but id assume harsher than normal....

Or it unlocks on acceleration, or the lock up friction slips on acceleration but there is enough there on idle and decel to cause this

[Drift_R32]

dropped it off to WA performance today

in safe hands..