05/11/2025
Todays focus - ZF Gearbox controllers! A bit of an overview of the repair service we offer for these popular modules.
Starting with the “old faithful” AS-Tronic lid, fitted to 8 and 12 speed gearboxes from around 2005 onwards. There are three variants, GS 3.0, GS 3.3 and GS 3.6.
Electrically, these are quite basic, the PCB is only ever damaged if the vehicle is jump-started. However, the pneumatic “bottom half” does wear and will usually start to give intermittent gear selection issues accompanied with a fault code 155 or 3155.
We have outstanding quality, remanufactured pneumatic assemblies on the shelf, and can repair your PCB as required.
One of the most common items that we repair is the AS-Tronic Lite “power pack”, fitted to most smaller trucks between 7.5t and 18t, on a 6 speed gearbox. These essentially convert a traditional manual box into an automatic, selecting gears and actuating the clutch just like a (some would say learner) driver would.
These are a very problematic device – we see a wide range of failure modes. In the absence of any other issue, the hydraulic pump units will simply wear out until they can no longer build enough pressure in a morning, causing the truck not to start. More often than not some other failure will cause the unit to go down long before this, moisture ingress into the ECU or contamination of the hydraulic fluid damaging the valves are the main two problems that we come across.
A common fault code we see will be KL30-1 or KL30-2 (faults 4134 and 4135), often the vehicle will drive fine, occasionally in manual mode only. This is usually a sign that the ECU is getting full of water, so it’s important to pay attention to these faults before the vehicle leaves you stranded!
We can test and recondition your ZF AS-Tronic Lite power pack – repairing the ECU, building it into a shiny new casing and fitting onto a reconditioned and fully tested hydraulic actuator pack. A recent investment into old-core units will allow us to improve turnaround times. In the event that your power-pack is beyond repair, we can usually build and program a replacement unit for you.
Finally, a newer addition to the ZF family – the “Traxon”. This is essentially the successor to the AS-Tronic lids, and has moved the pneumatic actuation parts deeper into the gearbox, with a separate valve block up top.
With the higher processing power and complexity of these electronics comes more problems. We have identified the most common failure issue with these is caused by intermittent, total failure of the controller PCB. After much research and development, we can now offer a reconditioning service for this problematic control unit – Rebuilding the circuit board with more reliable components and processes. The unit will plug and play back onto the vehicle and give many years of reliable service.
