This evening I was watching the works recce Golf Rs manoeuvring on gravel. These are 4WD TFSI machines, successors to the Mk5 Golf R32, Haldex back end as you'd expect. I already knew that these recce cars had locked rear diffs, which they proceeded to prove with the outside wheels 'jumping' on tight manoeuvring. Fine, same with all tight diffs. What stood out a mile though was when they were jacked up, the wheels span in opposite directions quite freely, just like a free differential. No preload at all One for the electronics gurus I'd imagine. Do these observations stack up with the programmable aspects of Haldex?
The mk4 has EDL electronic diff lock Works off the abs to lock the rear wheels It's pants on the mk4 and can be coded out as can the esp
So that would apply to next gen Mk5/6? I've seen these cars again this evening. Absolutely obscene when manoeuvring. Wheels jumping/skipping as the diff tension unwinds. Can't be good for longevity!
When car is not running pump is also disabled and no pressure on haldex clutch plates hence free rotating? Just guessing
aye it would be sam chris i would think they would be but not 100% you should have a go of one in the snow chris sam do you have the diff lock and esp coded out on your a3 ?
diffs seem to last quit well if serviced brushs on the prechanger pump can go on the mk4 but can be changed you do hear of mk5 diffs going bang but thats down to who ever did the service taking the wrong plug out and draining diff insted of the haldex they then fill the haldex leaving the diff dry
The Golf MK6 , Touran, and 8P S3 and so on use a Gen 4 Haldex system. In 1998 "4motion" range, replaced the Synchro system as seen in the Golf 2 Rallye, Golf MK3 and Passat '35'. Synchro used a viscous coupling (common with manufacturers of that era) and the 4 Motion used a Gen 1 modular system by Haldex. Following Gen 1 was 2 (MK5 Golf), VW did not use Gen 3 ( as used on the Ford Kuga Mk1) and for the MK 6 models, VW/Audi uses Gen 4 Haldex system. Gen 1 (1998) and 2(2004) use the speed delta from front and rear axles to generate a pumping pressure. The pumping pressure is used to operate the pistons that ultimately actuate the clutch pack to engages the rear diff, thus transmitting torque. Like a CIS-E the Haldex controller determines the pressure on the clutch pack by operating a oil regulating valve to bleed off excess pressure. Gen 4 (2007) Haldex makes the pumping effect from front and rear axle speed deltas redundant by using an electric motor operated by the Haldex controller to generate pump pressure to engage the diff clutch pack. Like the previous version, a torque request is feed to the Haldex system from the PCM or ABS/ASR/Traction controlled modules via CAN to determine torque transfer from front to rear. There is now a Gen 5 (2012 vehicles onwards) which is to be fitted on the Golf MK7 AWD and Audi "Quattro" vehicles.
You are right about the MK5. Do not know what I was thinking despite writing down the dates of introduction!! Edited now.
A3 has been Fwd for 2 years now, in past it was on Oem engine management and Oem haldex ecu, not sure it ever had ESP?
they look much the same from the outside hard to tell with out look at the code on the bottom of the haldex unit OVA is gen 2 you have three codes for gen 4 not a clue what they are though it's all clever stuff i see it's getting hard to get gen 1 sport haldex controllers some one should work on dumping one
if you had a switch on the dash with ASR or ESP you will have the coding of the abs unit can be changed so you dont have it so it dont cut the power when it cuts in
