Another One for the X-Files
Back in 2003, when Transmission Digest hosted Showpower in Charlotte, N.C., I did a presentation called “Odds with an End,” an array of transmission malfunctions featuring oddities from the “X” files.
To this day I still receive calls from some who attended this seminar saying, “Hey, Wayne, I’ve got another one you can add to your X-file list!”
The idea of labeling transmission malfunctions as fitting into an X-file category is the result of knowing what fixed the problem but having difficulty explaining why.
Audi A8 Quattro
If you have ever driven an Audi A8 or any other high-end car using a ZF 5HP19 or 5HP24 transmission, you know these units are pretty smooth shifting and lockup is almost undetectable. This particular Audi came in with a customer complaint of a clunk or bump when the vehicle slowed. Initially, the car was diagnosed, and the unit was removed and rebuilt.
Mystery Noise in the ZF 5HP19/24
It’s not uncommon to hear customer complaints about a noise coming from a vehicle equipped with either a ZF 5HP19 or ZF 5HP24 transmission. The noise is most often described as a squealing or squawking sound and can be heard when the customer lifts his foot off the accelerator pedal. The sound is similar to that of a bad transmission pump and can be heard in any forward range but is most noticeable in first or second gear.
Falling Through the Cracks
And that is exactly what happens with a ZF 5HP24 transmission in an Audi, Jaguar or BMW. This problem will produce code P0731 (or P1722 with Jaguars) and it means a gear-ratio error in first. And it also may be accompanied by a complaint neutralizing at a stop when hot. The technicians on Transmission Rebuilders Network Worldwide (TRNW) are all too familiar with this problem. Yet, technicians around the country frequently allow this problem to fall through the cracks, which is why I thought of writing an article about it.
