02' 4.6is Supercharged / 107k / Trans. Fail. Safe

[RRPhil]

Issues with the fluid temperature sensor (which is taped into the wiring loom) are not unusual but (in my opinion) would be unlikely to produce the errors reported by your ECU







The ‘incorrect ratio’ codes imply that the signals taken from the turbine and output speed sensors do not add up to one of the ratios (for 1st & 3rd gear in your case) i.e. a clutch is slipping

Phil

[740ilDuke]

Phil, I’ve found a transmission that was rebuilt 15k miles ago, but has 215k miles on it. Should that be a concern? The shop says they did the works on it. Torque Converter, full clutch kit etc & valve body. I’m just wondering if i should be worried of the overall miles, or should it be alright & i’m overthinking it?

Thanks for your insight.

Originally Posted by RRPhil

Issues with the fluid temperature sensor (which is taped into the wiring loom) are not unusual but (in my opinion) would be unlikely to produce the errors reported by your ECU



The ‘incorrect ratio’ codes imply that the signals taken from the turbine and output speed sensors do not add up to one of the ratios (for 1st & 3rd gear in your case) i.e. a clutch is slipping

Phil

[RRPhil]

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

[740ilDuke]

It came from a 2003. I will try to get the number off the tag.

VIN: 5UXFB935X3LN80178

If that helps.

Originally Posted by RRPhil

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

[snik]

Originally Posted by RRPhil

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

That makes the 5HP sound awesome.
What's the main differences in failures and wear parts you've seen with the 6HP? Do they share any strengths or weaknesses with the 5HP, or is the 6HP totally different?


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[bcredliner]

FYI for those new to forum. RRPHIL is our resident expert on transmissions.

[740ilDuke]

Thanks Phil. I think Im in for a rebuild for sure. Looking at re manufactured units as well, but will have to investigate as to "what comes in the box". BMW dealership sells them for $3,000

What I've dug up price wise has gone like this:
Install / Swap $ Unknown - waiting on estimate
Fluid $ Have not priced - not sure how much Ill need to buy (chime in)
Rebuild $900
L51 Reman $300
Valve Body $600

I'm thinking I'll be about $400 on swap labor from a friend putting me around $2200 before fluid. I doubt "AAMCO" or whomever will be in that ballpark. I don't want to have to worry about it after this as I plan to ride this X5 for a long time.

[CleanIsFast]

If I remember correctly that trans fluid is very expensive. Something like $20/L, my guess is over 5 liters maybe more?

I actually have brand new liter in my closet from my old 4.6iS if you want it. Send me a message, I believe my 4.8iS takes different fluid now

[x5Alpine]

I would definitely go for a remanufactured box from BMW. It is literally a brand new transmission with a 2 year warranty. Germany only has 6 of them left for the 4.6is. A tech at my dealership just installed his new trans in his 2003 4.6is S3.

[740ilDuke]

Originally Posted by x5Alpine

I would definitely go for a remanufactured box from BMW. It is literally a brand new transmission with a 2 year warranty. Germany only has 6 of them left for the 4.6is. A tech at my dealership just installed his new trans in his 2003 4.6is S3.

I wonder if it includes the torque converter? #doubtIT

Approaches $3700 range with the BMW dealer option. oy.