After much effort, I finally own a ZF 5 HP-24A transmission out of a C5 Audi A6, and it’s in my shop, on a pallet.

I’m itching to take it apart, but there’s a good chance that this is a good one since the donor car was in the junkyard due to engine issues. Sadly, I have a very bad track record of destroying things, the first time I take them apart.  So, I’m thinking I should go find a bad transmission to take apart first.

Problem is, these transmissions are hard to find. The “A” at the end probably stands for “Allrad” as in 4WD, and that’s a rare variant. The RWD variant lacks the “A” hence just ZF 5 HP-24. Those are easy to find. I’m tempted to do that, but I’d like to know how similar the RWD is to the AWD. So I’ve been poking around on the Internet, trying to piece it all together.

One of the interesting challenges of this sort of task is that the information on the Web rarely reconciles, so I need to exercise some good judgment to make sense of it all. Fortunately, I’ve spent enough time lying underneath C5 Audi A6 4.2 V8 cars that I also have a reality-based frame of reference.

Things I’ve concluded to far:

• Audi calls this transmission the 01L. ZF calls it the 5 HP-24A, but it’s the same thing.
• For the C5 Audi A6 with the 4.2 liter V8, there’s an early variation through 2000, and a later one. The earlier variation has a code of “ECF” on the actual transmission plate, and a ZF part number of 1058 020 015. The later variation has a code of “FUL” on the actual transmission plate, and a ZF part number of 1058 020 031.
• These are unique to the Audi A6; the ZF 5 HP-24A is also used on the Audi S6 and the Audi A8, but those are different variations.
• The RWD variation (not used by Audi) is found in the high-end BMW and Jaguar cars built in 1997 through 2001 or so. For BMW, the different models each have a different variation of transmission yet the ZF part number always starts with 1058 000 and then has three digits that vary.  As to “different model” in the preceding sentence, for purposes of ZF part numbers, BMW considers the 740i and 740iL to be the same model, and the 540i Sedan and station wagon too. For Jaguar, it’s possible to find an XK8 and an XJ8 with the same variation in their transmission (i..e, an exact match) as long as both have the same type of engine.
• The theme whereby the 4WD version uses 1058 000 part numbers and the AWD version uses 1058 020 part numbers seems to stop at the transmission unit level. For the housings, for example, the RWD has part numbers that start with 1058 201 or 1058 301, and the numbers for AWD all start with 1058 201, though of course the last three digits are different.
• As to the housings and the parts that belong there, I didn’t notice any overlap in the part numbers. In other words, I found no parts common to both the RWD and AWD variants.
• As to the input shaft parts, yes! Match! Perfect match.
• As to the oil pan, some minor part numbers matched.
• As to the oil supply, the pump was different, but some minor parts matched.
• As to clutch packs, identical. Yay!
• As to planetary drive groups, identical.
• As to brake groups, identical.
• As to the duct plate, the plate itself and the wiring harness were different but many components were identical, down to even the valve orifice sizes. Isn’t THAT interesting?
• As to the valve body, identical according to one site, not so according to another.
• As to the solenoids, I found them to be identical. That was very interesting, too. Also: of the three solenoids, the two outside ones have the same part number, which is different than the one in the center.  The solenoid replacement kit part number is also common to the RWD and AWD, both.
• As to the replacement kits, the fiber clutch kits and steel kits have the same numbers for RWD and AWD, both.
• The overhaul kits, for everything including the kitchen sink, are not identical for RWD and AWD.

This all makes sense to me. When it comes to the housing, the output aspects, and the oil pan, the RWD and AWD are different. As to internal parts, they’re identical or almost so.

It’s interesting to me how much the solenoid part numbers overlap with the more-common ZF 5 HP-19 variants too.

So, certainly, if I go disassemble a RWD variation I’ll still learn a lot about the AWD variation too.