One of our customers experienced his Audi D2 S8 engine stalling when the vehicle was stopped, as in the torque converter wasn’t slipping when it should have been. We recommended he replace this part. He did, and the problem was solved.
The ZF 5HP-24A is an electronically controlled transmission, but it would be more precise to say that the valve body is electronically controlled, and the internals of the transmission are hydraulic, controlled in turn by the valve body .
The valve body consists of four main aluminum housings that are screwed together.
After many years of wear and tear, then under certain conditions, a pressure spike can slip past the pressure regulator (elsewhere in the valve body) and crack part of the casting located at the upper rear of the valve body, when installed in the car:
If this happened to you, then you should certainly replace the part or get it fixed by someone who does precise aluminum welding. We do offer this part for sale, used but complete with the various internals in case you opt to not weld the cracked part instead.
There’s some potential confusion as to the middle three digits being “327” vs. “427” where the former is what’s in the spare parts catalog and the latter is what we see on the casting. As we understand the US ZF distributor, before the part is machined it’s a “427” but after the part has been machined, it officially transitions to have a “327” part number, as in the catalog. Machining can cause a casting to evolve, so to speak, into more than one officially variation of the final result, hence the need for different part numbers. For what we offer here, however, it’s a non-issue. By the time it’s left the ZF factory, 1058327059 and 1058427059 are the same, as far as practical implications are concerned.
As to its structural internals, the ZF 5HP-24A had two main versions, an early version (used on the early A8 Quattro 4.2 V8) and a late version (used on the A6 Quattro 4.2 V8 and the later A8 Quattro 4.2 V8). You know you have an early version if the valve body has five green solenoids; that is the most obvious visual cue.
The early transmission type has letter codes of “DPZ” or “DSM” or “DTE” — all for the Audi A8, production date through 12/98. For that you would need the early valve body unit, part number 1058327059 or 1058427059. You can order it from our D2A8parts.com website here, and pay with PayPal or a credit card (via Paypal).
The later transmission type has letter codes of “ECF” or “FBC” or “FUL” for the A6, “FBD” for the S6, and “EDG” or “FBF” or “FBG” or “FUN” for the later Audi A8, later as in, production date after 12/98. For these you would need the later valve body unit, part number 1058327068 or 1058427068. You can order it from our D2A8parts.com website here, or our C5A6 website here. Either way you can pay with PayPal or a credit card (via Paypal).
We recommend that you not fix just the symptom. This sort of structural crack suggests your pressure regulator might be malfunctioning, which in turn might well damage some other parts too, including the rim of the clutch “A” drum, in which case your car loses 1st, 2nd, 3rd and 4th since these all depend on that clutch working. The only fix for that is to remove the transmission and replace the clutch “A” drum — a problem that’s best prevented. This requires work on a separate housing yet, not the one being offered here.