5HP30 vs 5HP24 auto trans

[Hyper]

According to ZF docs and BF members, late 850's and early M60-based 840's got the 5HP30 rated at 560nm. Late M62-based 840's got downgraded to the 5HP24 rated at 440nm. There are ratio differences.

Furthermore my understanding is that the steptronic feature relates to the TCM and shifter rather than the tranny.

Three questions: Is there any history of turbo apps or engine mods burning out the 5HP24? If I was losing sleep over torque ratings, is the 5HP30 a straight forward mechanical swap to the 5HP24? Would the (5HP24 steptronic) TCM be happy driving the 5HP30?

Speculations are welcome. Thanks.

[Auraraptor]

I am curious about the last question as well....as I want to try a V8 Steptronic TCM in a late 850 and see what it does.

5HP24 is smoother and quicker shifting. 5HP30 is more robust.

5HP24 can handle supercharged M6x V8s without an issue.

Can you elaborate on the ratio differences? I had the same ratios for both.

[Hyper]

I just now pulled these numbers from the dot PDF's for ZF spare parts catalog. Differences are subtle but officially listed by the manufacturer. Correction on the 5HP24 torque rating: is 420Nm, not 440.

5HP24
420Nm
1st: 3.57
2nd: 2.20
3rd: 1.51
4th: 1.00
5th: 0.80
rev: 4.10

5HP30
560Nm
1st: 3.55
2nd: 2.24
3rd: 1.54
4th: 1.00
5th: 0.79
Rev: 3.68

[olinjohnston]

There are "Steptronic" versions of the 5HP30, just not in BMWs. The Aston Martin DB7 Vantage used it even in 2003 (with a very powerful V12) for example.



The swap from a 5HP24 to a 5HP30 is not economically feasible as there are significant technical differences. While the early one is WAY overkill for use in an 840Ci, both transmissions routinely fail in stock cars anyway. There is no use in going through with the swap (even if it was possible) since there are THOUSANDS of supercharged 540is racing around, as well as X5s/Range Rovers towing boats using a 5HP24 with no issues. If you're planning a boost project, just do it. If the transmission fails, then just swap it for a manual at the same cost as a 5HP30 Steptronic retrofit.

[Hyper]

Sounds like a plan.

ZF docs have the 5HP30 continuing on, mated to the uber-rare 850/M73 which I assume is steptronic.

[Auraraptor]

Quasi-steptronic. Yes it shifts +/-, but it lacks a sport mode or the ability to shift into 1st when the engine is warm.

[xatlas0]

Th 5HP24 is a downgrade over the 5HP30 in terms of strength. I have seen 5HP24s fail in many ways, including hard part failures. The only way I have ever seen a 5HP30 fail is due to the known check ball flaw. In comparison, I have held a bifurcated A clutch carrier in my hands from a stock E39 540. The stock engine sheared the carrier apart. I have held the same part on a 5HP30, and it weighs about twice as much as the part on the 5HP24. Both transmissions suffer due to poor fluid change practices. ("lifetime fluid", yeah, right!)

There have been several members with SC-ed E39 540s that have had their 5HP24s fail in a matter of weeks. I remember one in particular, about three years ago. He was so excited to get the SC. Then, about 4 weeks later, he posts up that he had munched his trans.

Like others have said, it is difficult to switch from a 5HP24 to a 5HP30, as the harnesses and TCMs are different. You would also need a modified driveshaft, as the 5HP30 is significantly longer and larger than the 5HP24.

[paulmer]

Get a Getrag 226.

[Chamberlin]

Th 5HP24 is a downgrade over the 5HP30 in terms of strength. I have seen 5HP24s fail in many ways, including hard part failures. The only way I have ever seen a 5HP30 fail is due to the known check ball flaw. In comparison, I have held a bifurcated A clutch carrier in my hands from a stock E39 540. The stock engine sheared the carrier apart. I have held the same part on a 5HP30, and it weighs about twice as much as the part on the 5HP24. Both transmissions suffer due to poor fluid change practices. ("lifetime fluid", yeah, right!)

There have been several members with SC-ed E39 540s that have had their 5HP24s fail in a matter of weeks. I remember one in particular, about three years ago. He was so excited to get the SC. Then, about 4 weeks later, he posts up that he had munched his trans.

Like others have said, it is difficult to switch from a 5HP24 to a 5HP30, as the harnesses and TCMs are different. You would also need a modified driveshaft, as the 5HP30 is significantly longer and larger than the 5HP24.

Thread revival!

Agree with everything here, other than you probably had a sheared A drum due to a failed pressure regulator on the lower front valve body (scored bore) allowing 500+ PSIG to go where it shouldn't go; nothing to do with the stock power of an M62 motor cracking the drum. Change the fluid and filter on the 5HP24, update the pressure regulator early on (either TransGo or Sonnax) and the 5HP24 will last a LONG time.

[toomanyparts]

Just wanted to chime in and note that there are M62 based E31s with the 5HP30 and steptronic. Not sure why.

[Chamberlin]

Just wanted to chime in and note that there are M62 based E31s with the 5HP30 and steptronic. Not sure why.

That's really interesting - I'm assuming the reason for this is similar to the reason that some 840ci cars were built side by side with M60 and M62 motors? (i.e. not a hard cutoff, using up supplies of older components?)

It sure would be neat to find one of those.

[Higgilo]

Thread revival!

Agree with everything here, other than you probably had a sheared A drum due to a failed pressure regulator on the lower front valve body (scored bore) allowing 500+ PSIG to go where it shouldn't go; nothing to do with the stock power of an M62 motor cracking the drum. Change the fluid and filter on the 5HP24, update the pressure regulator early on (either TransGo or Sonnax) and the 5HP24 will last a LONG time.

I’ve had some problems with my 5hp30 mated to my 850ci M73. (#84 of 363 produced for North America. An earlier post commented on the rarity of this combination. It is steptronic, but no sport program)
I’ve already blown the A drum on one 5hp30, and was able to source another complete trans for a reasonable price. I rebuilt the VB from the blown trans with the upgrade kit, but the typically absent check ball was in its proper place, so that was not the root of the problem.
I used the rebuilt VB from the blown tranny in the new transmission, and the car still does what I think may have contributed to the early death of the first trans.
When the engine is cold, the transmission seems to “drag.” That is, when I lift off the gas, there seems to be an inordinate amount of engine braking, it is really noticeable.
Would this be a symptom of a failed pressure regulator?
I really don’t want to blow up another a drum, as I think I got the only reasonably priced 5hp30 in the US.



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[Chamberlin]

I’ve had some problems with my 5hp30 mated to my 850ci M73. (#84 of 363 produced for North America. An earlier post commented on the rarity of this combination. It is steptronic, but no sport program)
I’ve already blown the A drum on one 5hp30, and was able to source another complete trans for a reasonable price. I rebuilt the VB from the blown trans with the upgrade kit, but the typically absent check ball was in its proper place, so that was not the root of the problem.
I used the rebuilt VB from the blown tranny in the new transmission, and the car still does what I think may have contributed to the early death of the first trans.
When the engine is cold, the transmission seems to “drag.” That is, when I lift off the gas, there seems to be an inordinate amount of engine braking, it is really noticeable.
Would this be a symptom of a failed pressure regulator?
I really don’t want to blow up another a drum, as I think I got the only reasonably priced 5hp30 in the US.

I called TransGo a few days ago to order another scarf ring set for the second 5HP24 pressure regulator kit I have on deck for my 2000 E38 Sport... While I was talking to them I asked if they had any pressure regulator kits for the 5HP30, and they firmly told me "No". He wouldn't go into any details and seemed like he just wanted to deal with my order, not talk about the 5HP30....

So although I know the 5HP30 has a (identical? similar?) pressure regulator on the valve body, I've yet to see any info on the interweb saying it can score like the 5HP24 and cause A drum cracking on the 5HP30.

BTW, my first BMW was an M73/5HP30 850Ci, #308 of 363. The previous owner warned me it sometimes went into Trans Fail Safe, so I always drove the car like a granny LOL! I now have another 5HP30 E31, but this time a '95 M60 840Ci. I want to do a drain/fill/filter soon, but I probably won't pull the valve body since I'm worried I will mess up a perfectly functioning 76K mile transmission. But after working on my two 5HP24 trannies, I do have a LOT more confidence from when I owned my '97 850Ci seven years ago!

Tempted to buy that ZF upgrade kit just to have it....it seems to have all the upgraded parts available from ZF. If that hasn't helped your situation though, I'm scared that you may have some issues on the 'upper' half of the transmission (but both the replacement tranny and the original tranny? doubt it)... so before you even go down that route, I'd seriously look into having all the solenoids tested and replaced as needed. Normally those solenoids are pretty bullet proof, but if you've got dragging, I could certainly envision wrong or extra clutches being engaged/partially engaged causing dragging...