GearBox.

[RRPhil]

Hmmm. Not wishing to be too pessimistic but, as a worst case scenario (& hopefully it will turn out that there’s a simpler and less costly electrical/electronic cause), you may have had an A-clutch drum failure. These were all the rage with the 5HP24 until the end of 2000, when a strengthened A-clutch drum was introduced, and clearly your 2002 vehicle should have the upgraded drum. However, the later drums do still occasionally fail.

The A-clutch is used in 1st, 2nd, 3rd and 4th gears so the control system immediately selects 5th gear (B-clutch & D-brake) if it detects unexpected slip across the A-clutch. Reverse uses the C-clutch & F-brake, so is unaffected by this failure.

Small parts of the broken drum would most likely end up in the sump, stuck to the magnets, if this were the cause.







We really need to determine if your transmission is failing safe to 4th gear or to 5th gear.

Phil

[Henrym3]

Originally Posted by RRPhil

Hmmm. Not wishing to be too pessimistic but, as a worst case scenario (& hopefully it will turn out that there’s a simpler and less costly electrical/electronic cause), you may have had an A-clutch drum failure. These were all the rage with the 5HP24 until the end of 2000, when a strengthened A-clutch drum was introduced, and clearly your 2002 vehicle should have the upgraded drum. However, the later drums do still occasionally fail.



The A-clutch is used in 1st, 2nd, 3rd and 4th gears so the control system immediately selects 5th gear (B-clutch & D-brake) if it detects unexpected slip across the A-clutch. Reverse uses the C-clutch & F-brake, so is unaffected by this failure.



Small parts of the broken drum would most likely end up in the sump, stuck to the magnets, if this were the cause.















We really need to determine if your transmission is failing safe to 4th gear or to 5th gear.



Phil

I’ve had a look round on various sites and can’t find the information on how to determine whether it’s failed in 4th or 5th gear. Is it worth draining and removing the sump to check the magnets for debris. Selecting sport doesn’t show what gear it’s failed in and I assume this is because it’s goes straight to failsafe.
Again I much appreciate your input.
My wife managed to pick me up of the floor after I asked for some quotes from a few shops.
I did check the connections in the e box, dry as a bone and no sign of any corrosion on pins.


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[RRPhil]

Based on 275/40 R20 front & 315/35 R20 rear tyres the rolling radius is around 361mm

Axle ratio for the 4.6iS is 3.9091 (i.e. 43/11)

The transfer box ratio is 1:1

4th gear ratio for the 5HP24 is 1.0000, and 5th is 0.8037

Hence, the driveline is geared at 21.6mph/1000rpm in 4th and 26.9mph/1000rpm in 5th

At 50mph, with no converter slip, that’s equivalent to 2310rpm engine speed in 4th and 1860rpm in 5th

At 60mph, with no converter slip, that’s equivalent to 2775rpm engine speed in 4th and 2230rpm in 5th

Clearly, in addition to the accuracy of the speedo which will be between 3% & 5% fast, the main problem is the fact that, in failsafe, the lock-up clutch is unlocked in the torque converter.

To get zero slip across the converter requires a fine balance between drive & overrun which isn’t easy to achieve on the road when there’s traffic to think about as well as gradients, speed limits, etc. but maybe it’s worth trying to drive at a steady 50mph or 60mph and reading off the engine speed to see which gear it corresponds with?

Phil

[Henrym3]

Originally Posted by RRPhil

Based on 275/40 R20 front & 315/35 R20 rear tyres the rolling radius is around 361mm



Axle ratio for the 4.6iS is 3.9091 (i.e. 43/11)



The transfer box ratio is 1:1



4th gear ratio for the 5HP24 is 1.0000, and 5th is 0.8037



Hence, the driveline is geared at 21.6mph/1000rpm in 4th and 26.9mph/1000rpm in 5th



At 50mph, with no converter slip, that’s equivalent to 2310rpm engine speed in 4th and 1860rpm in 5th



At 60mph, with no converter slip, that’s equivalent to 2775rpm engine speed in 4th and 2230rpm in 5th



Clearly, in addition to the accuracy of the speedo which will be between 3% & 5% fast, the main problem is the fact that, in failsafe, the lock-up clutch is unlocked in the torque converter.



To get zero slip across the converter requires a fine balance between drive & overrun which isn’t easy to achieve on the road when there’s traffic to think about as well as gradients, speed limits, etc. but maybe it’s worth trying to drive at a steady 50mph or 60mph and reading off the engine speed to see which gear it corresponds with?



Phil

My main concern with trying that is that it’s at least 2 mile of stop/go lots of traffic lights and roundabouts to get to a busy dual carriageway. If the drum has gone how much additional damage might that cause as well as all the slippage to clutches. It is about the same distance of 2 mile to a transmission repair centre who have diagnostics, would the diagnostics they have be able to tell which gear it’s in and do an accurate assessment of the problem. I’d rather run the 2 mile and pay the roughly £100 fee than risk further damage potentially spreading all those bits of metal around.


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[Henrym3]

Originally Posted by Henrym3

My main concern with trying that is that it’s at least 2 mile of stop/go lots of traffic lights and roundabouts to get to a busy dual carriageway. If the drum has gone how much additional damage might that cause as well as all the slippage to clutches. It is about the same distance of 2 mile to a transmission repair centre who have diagnostics, would the diagnostics they have be able to tell which gear it’s in and do an accurate assessment of the problem. I’d rather run the 2 mile and pay the roughly £100 fee than risk further damage potentially spreading all those bits of metal around.


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Is the 4.4l gearbox internals the same as the 4.6l. Will the bell housings change over and the transfer case. There are plenty over here with warranty but the advertised 4.6 are like rocking horse sh@t.


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[RRPhil]

As well as the larger torque converter, the ‘034’ version for the 4.6iS has an extra clutch plate in the D-brake (5 instead of 4) and the upper valve block has different KV-B and KV-E valves. Yes, you can swap the bellhousing over with the torque converter. The bellhousing casting is the same, it just has the radial webs machined to provide clearance: https://xoutpost.com/1137899-post2.html

Phil

[aureliusmax]

Posting some of OP's photo attachment error codes into text for ease of searching for anyone needing in the future once issue is resolved.

IKE: Electronic Braking-force distribution
IKE: EGS signal line disturbed

Lucky to have Phil respond to your thread. He's an amazing resource and appreciated very much on the forum.

[Henn28]

Originally Posted by RRPhil

As well as the larger torque converter, the ‘034’ version for the 4.6iS has an extra clutch plate in the D-brake (5 instead of 4) and the upper valve block has different KV-B and KV-E valves. Yes, you can swap the bellhousing over with the torque converter. The bellhousing casting is the same, it just has the radial webs machined to provide clearance: https://xoutpost.com/1137899-post2.html

Phil

The whole gearbox, including the bellhousing is a single casting, isn’t it? Or does it come off of the actual transmission casting? Funny I didn’t think to look at it when I took the motor out of my x5.

I worry that I’m going to roast my 4.4 TQ by having it bolted to the 4.6. So far so good though. At least parts will be easier to find if it does blow up. I have thought about finding a 4.6 TQ and machining the webs in the bellhousing if I ever do need a new TQ. I wonder how this combo would work in theory for HenryM3? I.e, OP could find a significantly cheaper 4.4 5hp24 and use his TQ and bellhousing. Anything to be gain or lost, aside from perhaps saving some money?

[RRPhil]

The 6-speed boxes have a single-piece casing, but the 5-speed is made up from four sections. The bellhousing, the oil pump housing, the main casing and the rear adaptor plate.



Clearly BMW & ZF thought it was worth the expense of developing a new version of the 5HP24 specifically for the 4.6l engine. The 280mm L51 torque converter will match the torque and power characteristics of the engine better. There must be some vulnerability in the D-brake, too, (engaged in 3rd & 5th gear) as they chose to increase its capacity by 25% for the 4.6l. I’m not sure why the B & E clutch valves were changed for the 4.6l but, again, car companies don’t go to the expense of doing stuff like that for no reason. I assume that the transmission controller is programmed differently for the 4.6l too.

I hadn’t heard any reports before of how the 4.4l version of the 5HP24 (1058 000 029) behaves in a 4.6l (1058 000 034) so I’m very interested to hear about your experience.





Phil

[Henn28]

Great info, thanks Phil. I never drove an OE 4.6is, so I can only compare my current set up to when the car was a 4.4i (we bought it new in 2002). The 4.6 is a great upgrade to it and makes it one of the most fun bimmers I've ever owned, second only to the E36 M3 sedan...I really wish I still had that car.

The power comes on like a freight train at around 3000 rpm. Before that its not as noticeable as I think it should be from 350ish hp and ft lbs. I wonder if this is due to the fact that most of the 4.6 extra power comes from top end changes or does the fact that its hooked up to the stock 4.4i 5HP24 and TQ have something to do with it. The final drive in the 4.6is was different as well and more geared towards acceleration I believe (4.4i is 3.64). I am glad I stuck with the 4.4i dffs though as the car gets atrocious MPG as it is now! I had read that the 4.6 was thirsty, but lifted and AT tires don't help at all.

I settled on using the 4.4 OE 5HP44 because it was fairly new to me. I bought a remanufactured piece and installed it in 2019 due to years of slipping at lower RPM. My kids were driving the car at the time, and it sport mode would reduce the slippage to an acceptable level, until it didn't and the gearbox finally crapped out on my daughter, fortunately not too far from home. She skipped failsafe mode and went right to paperweight mode.

I struggled to find a 4.6is 5HP24 when I did my motor swap, and using the OE gearbox seemed a little less complex from a computer mod standpoint. Kassel update my 4.4 DME with his 4.6 numbers and it fired right up and runs fine on with the motor/gearbox combo.

I suspect heat is perhaps what will cause problems first? I've been thinking of putting a standalone CSF Race universal cooler up front for the gearbox, with an inline 80 deg C thermostat. I'd do this as a standalone mod, or maybe with a CSF M5 radiator and cooler t-stat.

The fact that the bellhousing is separate makes me wonder what a 4.6is torque converter, on the 4.4i transmission would do for drivability and longevity?

Thanks, agian for the insight.