Specific to the RS6
The RS6 has a unique sub-variation with letter code GAG and ZF part number 1058020035.
It can be difficult to find a replacement used transmission for the RS6. The other sub-variations are not interchangeable with the sub-variation for the RS6.
Internally the RS6 sub-variation of this transmission is closest to the S6 sub-variation, but the team that built the RS6 needed every bit of available space under the hood. The C5 A6 4.2 V8 and the S6 already have limited under-hood space, plus then the RS6 creators added two turbochargers with intercoolers plus all the plumbing that goes along with that, so underhood space is at a premium yet they avoided resorting to hood scoops for extra space. If you have a close look at our pictures of the RS6 transmission, you can observe the various places where the case has indentations or hollows to make room for something or other close by.
Another aspect unique to the RS6 is that its engine-to-bellhousing bolt pattern is different than that of the C5 A6 4.2 V8, the C5 S6, the D2 A8 and D2 S8. The bolt pattern is instead the same as on the D3 A8. Perhaps the RS6 engine was an exploratory project to the intended benefit of the D3 A8 engine design. Certainly, someone was planning ahead.
For either or both of the above-mentioned reasons, the RS6 sub-variation of this transmission has a custom case, cast specifically for the RS6 and yet the internals are essentially as for the S6 sub-variation.
Due to the crude-looking custom-case case, when we observe the RS6 sub-variation of the ZF 5HP24A transmission side by side compared to the other sub-variations of the ZF 5HP24A transmissions, it is like seeing a Frankenstein monster compared to a human. Everything is basically there but it’s all somewhat distorted.
Our Target Customer
These used Audi C5 RS6 ZF 5HP24A Tiptronic automatic transmissions are being offered for the RS6 owner who likes the car enough to not give up on it yet, even though it has developed automatic transmission problems.
This owner likes the car in stock form, including the automatic transmission, and would like it to simply be restored to good working order, with some reason to believe that this isn’t the beginning of the end, as in: the car will continue to provide reliable enjoyment without becoming a money pit from here on.
We understand that specialists for these transmissions are rare, and that most transmission shops won’t touch them – and this no doubt adds to your frustration.
For these reasons, we hope today is a happy day for you, finding a parts source specializing in the ZF 5HP24A, with enough of an understanding to give you a high level of confidence that this replacement transmission is likely to provide many additional years of viability to the life of your RS6.
You bought your Audi not simply as transportation but to have an enjoyable ownership experience. Your cultural needs remain in effect when buying a replacement transmission. We are sensitive to that point.