Hey guys,

so the other day I was driving my KH Verada down hill; I would have been doing about 70km/h, I moved the shifter back from D into 3rd, got to the bottom of the hill, moved back into D and I think the gearbox flared/slipped a bit (maybe 800rpm). Its got 126,000KM on it and its been serviced at 50,000KM, 100,000KM & 110,000KM (I got the car at 108KM).
Otherwise, the gearbox is silky-smooth and its never missed a beat (touch-wood), I continued driving and it was shifting as normal, and its shifted normal since. But I'm freaking out there could be something wrong? Not really mechanically inclined, so any ideas/suggestions would be much appreciated.

Thank-you!

My suggestion would be to check the transmission fluid for colour and smell which could indicate that the transmission fluid needs changing - it should be red, not brown, and not smell burnt. If you think it's brown or burnt then it probably indicates that it needs changing. You'll probably find it never has been changed - my TL at 104,000km had never been changed...just had normal services but drove perfectly.
Other than the above I think there is little you can do. I wouldn't be too worried about this isolated instance of flaring. In the absence of any other indication of trouble I'd just put it down to a 'glitch'.
Good Luck.

Guys, there is a big misconception about changing fluids in transmissions. Changing the fluid in a transmission is not as simple as dropping the sump plug, draining out 4 litres or so of oil and then plugging it back up and filling it with new oil.

Basically in most cases, when you drop the plug, only a litre or two at utmost best drops out the box. Hence when they fill it up, it takes 1 to 2 litres. You have a mixture of good oil and bad oil. The idea is if you do it regularly you'll have better oil as it ultimately all gets cleaned out. Most places, like Mitsi, and even trans specialists do the usual $200 to $250 service which involves doing just this.

A transmission specialist will happily do a full trans service which involves running the car, having hoses connected to both the input and output of the trans and pumping/flushing out all of the fluid which is held up in the torque converter. This process gets all the old oil out, but the issue is it uses lots and lots of oil which costs $$$$. Expect this sort of service to be around the $300 to $350 mark to do.

But the first method is widely acceptable, provided, and the key is you do it regularly, ie every 20,000 km's. If you've left your trans go for 60,000 - 70,000 km's, this will probably require the full flush as if the oil is pretty black (and not red) even with a half a change its still gonna be blackish/red and will need to be done again to get that gunk out.

Just thought I'd offer this so most people are aware in case you weren't.

Boosty

Well this has happened again, last night after driving in the city. The car now has 132,000KM and has had a fluid drain and refill. The last lot of fluid came out completely black so I'm guessing maybe its time for another drain and refill? Its it possible my wave spring has broken and lodged itself in something? I'm lost....

Sounds like another drain and refill with new filter will not hurt. You may not have to get too worried yet, My old TF started occasionally flaring between 2nd and 3rd, and 3rd and 4th gears at 130,000km but it now has over 300,000km without any work done to it just oil + filter changes at the recommended times.
One thing that you could try is to disconnect the battery over night and after reconnecting it, idle the car for a few mins and then take it for a good 30+ mins drive, this resets the computer and it may set back in without the flaring.

Keep in mind though if you do try this procedure, the idling may be out of whack.. it may idle high or low, or even have some flaring with gear changes but give it a good drive first and see if it settles in. If not, try disconnecting it again for 30 mins then try again. This has always worked for me.

Are you giving this car a hard time? That can turn the fluid black real quick due to heat. Fitting an oil cooler will help heaps with this. I used to have black oil within 15,000km of changing it. Since putting the cooler on 2 years ago I haven't changed the oil and it is still red.

Maybe ahahaha. I should look into this. Are they hard to install?

Are you giving this car a hard time? That can turn the fluid black real quick due to heat. Fitting an oil cooler will help heaps with this. I used to have black oil within 15,000km of changing it. Since putting the cooler on 2 years ago I haven't changed the oil and it is still red.

Actually, now that you mention it, it only ever does it when its been driving for like 2 hours and its really hot.

If you can make a couple of brackets and cut/connect a few hoses you'll be right. I got mine out of a 2nd gen Magna. You can also buy generic new ones that may have mounting brackets with them. Do a search on here as there are lots of threads on it with all the details.

Might also be time to add some of that "stop slip" stuff - Madmagna recommends a certain brand.
Here is the link to the "How-to" on transmission coolers: http://www.aussiemagna.com/forums/showthread.php?t=74298