a cautionary tale....

[skiwi]

hey long time since i posted - here is a tale of woe with a happy ending....

a couple of months ago i had a "coming together" in my rs6 with another vehicle. t-boned them. i managed to reduce the length of my car by about 100mm, and write their car off.

however, my car being an rs6 meant that, although the front end was stove in only 100mm, a small matter of 5 radiators were kaput (engine coolant, transmission, engine oil, power steering, hvac). throw in the cost of a new bumper and the total cost of my mistake was about $30k(!) as a consequence of paying above normal for insurance for most of my (audi) vehicular life i got to choose the best panelshop in town and they did a job that was frankly, superb. the car looked better than new, the new paint was deep, even and perfectly matched. the new bumper and chrome made the car look fantastic. net cost to me was $500 excess. after 20 years of no claims, i was happy and 'ahead'...

we had chosen to replace the transmission oil cooler, due to surface damage (crushed cooling fins), although it wasn't leaking after the accident.

however over the course of the last few weeks the car began shifting abruptly and becoming noisy in step off. frankly the transmission performance had been deteriorating anyway, and i was bracing myself for the inevitable expensive repair at some point in the not too distant future. however this was much much worse. once the car even refused to step off even though in 'drive' and throttle depressed. it just spun away in neutral and then with a 'bang' we were off.

i had had a conversation with the panelshop about their capability to replace the radiators and had been assured that they could do the work (i had the t-belt replaced by the dealer whilst the car was sans front end). but i was suspicious that the fluid lost in the cooler hadn't been replaced, so i asked the dealer to check the transmission fluid and top up if necessary. they came back to me with the news that the transmission was 3 litres short of fluid! as a consequence of the top-up, shifting behaviour was good again, but there was still a nasty whine when stepping off. expensive transmission repair time i thought....

the obvious conclusion was that, in replacing the oil cooler, the panelshop hadn't replaced the fluid. not good. especially as i was likely to be caught up in discussions with the panelshop over a bill likely to be in excess of $10k...

as many will know, the 5hp24a transmission is a "fill for life" unit (don't get me starting of the stupidity of that), and as a consequence, filling the transmission is a mission requiring an arm broken in 4 places, a ph.d and the patience of mother teresa.

after going back to the panelshop with the dealers story of having to add 3 litres of fluid (total of 9l in the unit), they flatly denied being responsible. things got more confusing when we managed to locate the old cooler and verify that it only contained 200ml of fluid and that the next obvious candidate, the fluid lines, were auto sealing, and we were left scratching our heads.

the panelshop were taking responsibility, even acknowledging that they did not attempt to replace fluids lost (their s.o.p), so i was happy enough so we took the car to a dedicated transmission shop for further diagnostics. they dropped the pan investigated and ended up replacing the filter, cleaning the pan, and fully replacing the oil.

the result is stunning - fast definite shifts, smoother operation and a transformed car. better than i can recall it ever being. the panelshop wore the costs.

the transmission shop confirmed that there were no leaks from the transmission, and that the pan had not been off. given that the car has been serviced from birth, there is no explanation of the loss of 1/3 of the transmission fluid, other than it had been short from birth.

with my last car (an s8 with another 5hp24a transmission) i got the tranny fluid replaced once, but i have neglected to do so with the rs. i can confirm that the transmission is never checked by the dealer (it's 'sealed for life' don't you know) - and so, unless you complain about poor shifting performance, it escapes attention.

the morale of the story - locate a good transmission shop, and get them to flush and replace the fluid and filter as a maintenance procedure at reasonable intervals (my car is 7 years old, and has 89k kms on the clock) -particularly if shifting performance is getting sloppy. our allroad is now booked in for the same treatment as the shifting performance has deteriorated, as a consequence of the towing it does.

overall a happy ending - i'm now happier and wiser than when i started - and the car is too....

dave
'03 rs6
'04 allroad tdi

[RichRS6]

Nice to hear a happy ending, I am looking at having the tranny flushed if I someone can recommend a specialist in the South West ???

[skiwi]

it is worth it just to ensure the levels are correct. it beggars beief that my tranny was probably low of fluid for a substantial time....

[Shoppinit]

It's a bit of a lottery... what if your box is fine, and by getting it serviced, you screw it up? This was the hobsons choice that I was faced with. I ended up getting it done by AUdi and they seemed to have done it correctly. Phew.

[skiwi]

the other realisation i came to with this experience is that the dealer outsources all substantial transmission work to a local specialist. i felt *way* more comfortable talking to the specialist who knew the type of 'box, th general issues with it, and could debunk some of the myths. he also offered to replace the valve body with one that had been modified to reflect late series changes...

he was quite catagorical that there was *no* issue on the box that was difficult to fix - the primary issue was the time and cost of removing and replacing the 'box in the first case. he could replace the clutches/brakes for <$2k nzd. but the labour for the removal/refit was about $4k.

he had an 5hp24 box ready as a replacement (for a bmw) i was surprised to see the tcc unit was quite small...

interestingly we think we are relatively hard done by with the unit, but he had a pile (literally 6 transmissions) all replacements for 6-speed gm holdens (v8's) which apparently fry their mechatronic modules very regularly. needs full replacement apparently.

[Shoppinit]

The TC is bigger on the RS6. Also the box is a modified 5HP24A, you can't just grab one off an A6 and expect it to last longer than a glass drumkit.

[skiwi]

The TC is bigger on the RS6. Also the box is a modified 5HP24A, you can't just grab one off an A6 and expect it to last longer than a glass drumkit.

not really - the 5hp24a is the awd variant of the 5hp24. amongst the 5hp24a family, the only thing that is unique in the rs6 box is the tcc. the rest is shared amongst the audi a6/a8 family. the "d/e" stage which iirc is shared only with the s8.

the only other difference with the rs6 is the output gearing which is unique (37/9), but the gearbox gearing itself isn't.

so it would be quite possible to remove a transmission from an s8 and swap it. you would need to replace the new box front diff and tcc with the old ones....

[Shoppinit]

I refer you to page 31 of the the RS6 training manual where the modifications from the standard 5HP24a are detailed:

[MoRS6+]

Wow, gotta admire that technology! Some clever <beep> going on there!

[Shoppinit]

Autoboxes are like black magic, they shouldn't work, but they do!

[skiwi]

I refer you to page 31 of the the RS6 training manual where the modifications from the standard 5HP24a are detailed:

as i tried to say, the gearboxes are substantially the same.

the increased pressure mentioned is due to a unique tcc, not the oil pump, which is the same. the transfer housing is not unique, as is shared with the a6/s6. i noted the "d" stage - which is shared only with the s8. as for the reinforced spur gear splines, i wouldn't die in a ditch over that. they are not replaceable parts anyway - so don't carry part numbers - i would assume that they are s8 (or perhaps w12) parts as well.