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View Full Version : What are the signs of needing a transmission rebuild?



dimi108
27-10-2008, 04:11 AM
I'm taking the car to the garage in two weeks to get the TC seal and rear main seal replaced in the Legnum. I'm paranoid i'll get a suprise call from workshop saying it'll need a rebuild.
The car runs really well when it's warmed up. But when it's cold and first start driving it, the gearbox doesn't change too smoothly from 1st to 2nd.
It could possibly be dirty transmission oil too.

I was wondering if anyone can list some common tell-tale signs that the transmission is dying.

bradc
27-10-2008, 05:17 AM
Well they will be changing the transmission oil at the time, so just make sure they change all the fluid in it to the right stuff and see how it goes.

Physician
27-10-2008, 05:34 AM
Hi buddy ....... don't worry too much as most, if not all, the tiptronic VR4 boxes 'grab', 'jerk', 'surge' when changing up from 2nd > 3rd when cold (albeit you say yours does this 1st > 2nd?).

I know many owners (myself included) that move over to tiptronic mode as soon as it has got into 2nd gear when cold so that the box has time to warm up and this stops the 'surging' into 3rd.

dimi108
27-10-2008, 05:44 AM
Hi buddy ....... don't worry too much as most, if not all, the tiptronic VR4 boxes 'grab', 'jerk', 'surge' when changing up from 2nd > 3rd when cold (albeit you say yours does this 1st > 2nd?).
Yeah? Ah, that's good. I thought i was doomed for a sec.
1st, 2nd and 3rd seems to be a bit rough when it's cold but after about 10 minutes of driving, the gear changes are quite good and i can't notice any jerking etc.

Hey Carsten, yeah i'll get him to do the full flush after he's changed the seals. I've still got a lot of the spare ignition and drainage hose so i'll give that to the garage to use as well :)
They need to flush all the muck oil out of the tranny cooler too as my first flush was a bit "rushed" and, well, i didn't get around to flushing the entire system. My bad.

Physician
27-10-2008, 05:49 AM
1st, 2nd and 3rd seems to be a bit rough when it's cold but after about 10 minutes of driving, the gear changes are quite good and i can't notice any jerking etc.


Ummm, maybe it is the ATF that needs replacing as my description in last post is pretty EXACT in that no issues with 1st or 3rd, just moving from 2nd > 3rd when cold and it only ever seems to do it ONCE and then it's all OK - probably when ATF has circulated all cogs and/or warm.

dimi108
27-10-2008, 06:03 AM
I think it could be the ATF as well as i know there is clean ATF and old, dirty ATF mixed together.
Should the car still be fine for the next two weeks with the dirty ATF still in there mixed with the new? I don't really want to have to flush the ATF before then if the car is going to get a flushing again in two weeks time.

Basically, i changed the transmission fluid and filter 4 weeks ago but i didn't flush the fluid out of the tranny cooler.
Will dirty ATF in there mixed with new ATF cause damage to the box?

Ryan
27-10-2008, 07:12 AM
Speaking from my own experience, the auto box is actually pretty strong unless you're absolutely brutal with it.

I had my TC seal fail on me and was bleeding ATF all over the place. I didn't know it at the time because I was examining the ATF dipstick incorrectly (ie: I did not park on level surface, cycle through gears with engine running and then check).

I lost about 4-5L of ATF and it was a struggle driving it. Getting going in the mornings was the worst as I had to try and reverse up my drive... I'd engage "R" and then floor it... it'd get purchase till about 1/2 way up the drive and then starved of ATF, I'd just hear the torque converter spinning away merrily but me going nowhere fast!

Eventually I'd manage to get out but every right hand turn around a traffic circle, I'd lose all drive and the revs would just go sky-high...

To make a very long story short, I eventually diagnosed it as a leaky TC seal, however, as I had been driving it around for the best part of 2 months with less than optimal levels of ATF the guys that I took my car to asked (not recommended) if I'd like to have it rebuilt. I thought about for a while, knowing the huge cost involved and thought - might as well.

During this, they obviously rebuilt the AT, fitted an ATF cooler and $3542 later I drove out with effectively a new box and the peace of mind that it was good for another 150 000km or so.

The choice is yours, either replace the TQ seal which will cost a lot to do in any case and then take your chances to see if it requires a rebuild later on. I don't know the history of your car or how you look after it but this is my experience on the subject.

I notice in your post that you mentioned it runs fine when warmed up... I think you'll find the auto in general is a little tweaky when cold, regardless of condition :)

dimi108
27-10-2008, 08:14 AM
Thanks Mr Ingles. Well earned rep for you +1.
Cool, i'll keep an eye on the ATF levels for now and top up every now and then if needed. It seems to only leak a few drips at the moment. Hopefully it will stay that way until i take it in for the seals.

Speaking of tough, you're not wrong. We've got a guy on OZVR4 who's trying to bust his tiptronic at the moment. He's whacked it into reverse doing 100km/h, doing rev limiter launches all day long, whacking it into park while driving and the thing is still going :inquisiti

So dirty fluid should be fine for now and the next 2 weeks until i get the seals done eh?

Ryan
27-10-2008, 10:01 PM
Yup, should be fine - I've just changed my ATF after nearly a year :p It was brown when it came out.

I'd really recommend fitting an ATF cooler if you can as the stock one is woefully inadequate.