Originally Posted by 740ilDuke (Post 1152289)

Damn...feels like its gone be awhile.

Originally Posted by RRPhil (Post 1152250)

I see 5HP24s at that mileage quite frequently and they’re in excellent condition (but others are completely ‘worn out’ at much lower mileages). When I check the thickness of the friction plates at 200k miles they’re often identical to brand new plates because the control system is so sensitive to any unplanned clutch slip that it immediately flags failsafe if there’s anything going on that could generate wear and damage. The long-term adaptions stored in the controller tweak the clutch control pressures over the years to maintain the shift times, again, protecting the clutches. Arguably at such a high mileage you should swap the controller with the transmission to preserve these settings.

Clearly, it’s a bit of a lottery fitting something at that mileage without knowing its duty-cycle history. If it’s been driven gently for the whole of its life the transmission could last indefinitely. If it’s been used for towing, frequent hill climbing, driven aggressively, etc. it may be much further through its fatigue life. Similarly, you have no way of knowing if the fluid has overheated in the past and therefore oxidised and massively reduced its protection/life.

Common failures at high mileages are the A-clutch drum snap ring groove (for transmissions built before November 2000), the B-clutch hub/C-clutch drum axial bearing failure, the F-brake piston seal (for transmissions built before August 2001) and wear in the torque converter lock-up clutch. Other than these well-known weaknesses the rest of the transmission is very durable. If the transmission has previously been rebuilt then the above issues may already have been addressed? Transmissions built after October 2001 have all the latest development fixes from the factory. If you want to know the date of manufacture of a particular transmission just let me have the serial number off the green plate riveted to the side of the casing.

Phil

Originally Posted by burninator (Post 1152290)

Sent to Vortech on 12/28

Originally Posted by RRPhil (Post 1152250)

I see 5HP24s at that mileage quite frequently and they’re in excellent condition (but others are completely ‘worn out’ at much lower mileages). When I check the thickness of the friction plates at 200k miles they’re often identical to brand new plates because the control system is so sensitive to any unplanned clutch slip that it immediately flags failsafe if there’s anything going on that could generate wear and damage. The long-term adaptions stored in the controller tweak the clutch control pressures over the years to maintain the shift times, again, protecting the clutches. Arguably at such a high mileage you should swap the controller with the transmission to preserve these settings.



Clearly, it’s a bit of a lottery fitting something at that mileage without knowing its duty-cycle history. If it’s been driven gently for the whole of its life the transmission could last indefinitely. If it’s been used for towing, frequent hill climbing, driven aggressively, etc. it may be much further through its fatigue life. Similarly, you have no way of knowing if the fluid has overheated in the past and therefore oxidised and massively reduced its protection/life.



Common failures at high mileages are the A-clutch drum snap ring groove (for transmissions built before November 2000), the B-clutch hub/C-clutch drum axial bearing failure, the F-brake piston seal (for transmissions built before August 2001) and wear in the torque converter lock-up clutch. Other than these well-known weaknesses the rest of the transmission is very durable. If the transmission has previously been rebuilt then the above issues may already have been addressed? Transmissions built after October 2001 have all the latest development fixes from the factory. If you want to know the date of manufacture of a particular transmission just let me have the serial number off the green plate riveted to the side of the casing.



Phil

Originally Posted by RRPhil (Post 1152305)

Without doubt, the single biggest problem with the 6HP26 is faulty solenoids. These cause the vast majority of issues with this transmission. The other main issues are:

• Transmission refuses to shift higher than 3rd gear (E-clutch slipping due to hydraulic leakage caused by wear in lead-free rear stator bush)
• Clunky 2-1 rollout shifts (Latest mechatronic firmware updates not performed)
• Clutch packs destroy themselves following fluid change and adaption reset (ECU cannot find new adaptions in time to prevent clutch plates burning up, due to change in friction coefficient)
• Complete loss of drive (Failure of output shaft spline through fretting corrosion due to lack of lubrication at factory)

Mechanically though, I would say it is a more robust transmission than the 5HP24. Having said that, Audi put the 5HP24A behind their 6.0 litre W12 engine and even the 353kW/560Nm Audi RS6 Plus, so the 5-speed running gear is certainly capable of handling more power/torque than the 4.6iS E53 delivers.

Phil

Originally Posted by burninator (Post 1152290)

Sent to Vortech on 12/28