[alexnaoumov]

Hello, E90 enthusiasts! This guide details the process of retrofitting an 8HP (8-speed automatic) transmission into a BMW E90, offering smoother shifts, better fuel efficiency, and improved performance compared to the 6HP (6-speed automatic). Based on my successful retrofit, this guide is tailored for the Bimmerpost community.

This guide will work for E9*, E8* and probably E7*.. Just make sure your car supports EWS4. The 8HP transmission requires EWS4 for Immobilizer Serial Number (ISN) compatibility. Otherwise, make it support it. I replaced my MSV70 to MSV80 for example on my 330i. It’s also possible to replace an manual or DCT to 8HP. You will need some creativity for that.

Disclaimer: This is an advanced (still in development) retrofit requiring technical expertise, specialized tools (e.g., ISTA, WinKFP), and familiarity with BMW electronics and reading schematics. Proceed at your own risk, and consult a professional if needed. Always double-check compatibility with your specific E90 model and engine. I will be offering the consult and remote coding if needed, check my company in my signature.

Prerequisites
• Tools: ISTA, WinKFP, multimeter, soldering tools, wiring harness supplies, BMW
diagnostic software.
• Skills: Knowledge of BMW electronics, wiring, and coding, ability to read and understand schematics
• Parts:
– 8HP gearbox (E84/E89 N20 for RWD, E7* N55 or E84 N20 for xDrive). Mechatronic from all E-gen 8HP gearboxes are interchangeable. It’s also possible to buy F-gen 8HP45 and replace the mechatronic.
– 8HP gearbox connector or complete used harness. I recommend to buy a complete used harness.
– 8HP or DCT shifter with 8-pin connector and 6x MQS pins (1x 61136954526 and 6x 61136931880 or 6x 61130056962 when you can’t crimp MQS)
– N55 torque converter or N20 flexplate (these are 100% compatible with N52 and N55).
– CAS3 or CAS3+ module (for EWS4 compatibility).
– FRM3 MAX Brose (FRM3 is needed for sure, not sure if MAX is needed)
– JBE III M (JBE III is needed for sure, not sure if MAX is needed)
– ZF Lifeguard 8 transmission fluid or similar
– Oil line adapter (canformance for example) or E84 oil lines
Optional parts:
– Newer ABG/ACSM module (to eliminate the ghost ACSM DTC).
– LCI paddle shifters (or resistors for non-LCI paddles).
– Secondary CAS3+ (for XHP license on different VIN).
– 8HP oil pan and filter
– New gearbox bolts and other stuff you change when replacing gearbox

Gearbox pin-out:

6HP Connector:



pin 1: EGS_MGA
pin 2: PT_CAN_L
pin 3:
pin 4: EGS_DOWN
pin 5: EGS_UP
pin 6: PT_CAN_H
pin 7: S_LOCK+
pin 8:
pin 9: 15WUP
pin 10: P/N
pin 11: S_LOCK-
pin 12:
pin 13: kl.31
pin 14: kl.30G
pin 15: ILOCK
pin 16: kl.31

GM Connector:



pin 1: kl.30G
pin 2: kl.31
pin 3: P/N
pin 4: kl.30G
pin 5: kl.31
pin 6: EGS_UP
pin 7: EGS_MGA
pin 8:
pin 9: EGS_DOWN
pin 10: PT_CAN_H
pin 11: PT_CAN_L
pin 12: 15WUP
pin 13: ILOCK
pin 14: SLOCK+
pin 15:
pin 16: SLOCK-

8HP Connector:



pin 1: P/N
pin 2:
pin 3: PA_BUS
pin 4: M_LIN
pin 5: PT_CAN_H
pin 6: PT_CAN_L
pin 7:
pin 8:
pin 9: 15WUP
pin 10: WIPPE+/-
pin 11:
pin 12:
pin 13: kl.30G
pin 14: kl.31

How-To:

1. Prepare the car.
- Convert to EWS4 if needed
- Install FRM3 and JBE III
- Make sure the DME is programmed with an automatic transmission mapping. This is needed so it supports torque interventions.
- Make sure the car is updated, especially the KOMBI so it can display the 8th gear.
- Make sure everything works as supposed before starting this project.

2. Remove the old gearbox.



3. Put them side by side, compare and drill one extra hole in the 8HP and elongate the other.



4. Prepare and install the torque converter:
Either replace the flexplate to the one your 8HP came with or install the 8HP N52/N55 torque converter. In case of N54 with 8 bolt crankshaft, use N55 torque converter with N54 flexplate.
N20 flex plate will fit on (most) N4* and N5* engines. N55 torque converter will fit on all N4* and N5* flexplates. There are a lot of possibilities here.



5. Re-pin the 6HP or GM gearbox connector to the 8HP connector under the car

GM:


6HP:



6. Install new gearbox
I recommend installing a new oil pan with filter while at it. I advice to replace all the bolts, also the torque converter ones.






6. Install the 8HP shifter
Use the part numbers from above.

At shifter pin the EGS_MGA wire in the M_LIN pin on the shifter. Make new wiring harness with KL30, KL31, 15WUP, PT_CAN_H and PT_CAN_L. I pulled them from my JBE and fusebox.




7. Reset the gearbox ISN so it can be used in the car.

I used this solution myself:
https://bmw-az.info/egs/33-bmw-e70-7...eter-file.html


8. Install one of these zbusb files with WinKFP.

These are all the petrol 8HP45 files for the E-generation vehicles, you can experiment with them:

E70/E71 N55 8HP45 xDrive
* 8646496
* 8646502
* 8646500
* 8646494
* 8646498
* 8646504
* 8646492
* 8646490

X1 E84 N20 8HP45
* 7642197 (sDrive28i)
* 8626054 (sDrive16i)
* 7642191 (sDrive20i)
* 7642189 (sDrive20i)
* 8626058 (sDrive28i)
* 8626056 (sDrive18i)

X1 E84 N20 8HP45 xDrive
* 8626050 (xDrive28i)
* 7642193 (xDrive28i)
* 8626048 (xDrive20i)
* 7642195 (xDrive28i)
* 7642189 (xDrive20i)
* 8626052 (xDrive28i)

Z4 E89 N20 8HP45
* 8611957 (sDrive28i)
* 8611953 (sDrive18i)
* 8611955 (sDrive28i)

9. Code CAS

It has to be fully coded as an automatic with SA205 in your VO. Also change these parameters by hand:

AUSWERTUNG_P_HW → nicht_aktiv
ABZUGSPERRE_PLOCK_C6 → nicht_aktiv

10. Short the parking lock connector
Short pin 1 to pin 4:



11. Replace the oil pan and filter on the 8HP and fill the gearbox following this procedure:
https://aftermarket.zf.com/app/contr...505690da53.pdf


Final:
If done correctly, you can start the car now and test all the gears. Make sure oil is filled take it for a spin and fix any issues if there are. Make sure there are no rattles.


Paddles:
Paddle wiring for 8HP. Only LCI paddles will work, or pre-LCI paddles with resistors. So pin 22 from JBE connector X14271 goes to the EGS (as standard), pin 38 goes to ground, 31 means ground. Just reuse old 6hp egs wire. If your paddles are not original and not wired the original way, disconnect the EGS_DOWN wire and wire it to ground.
Use this schematic:
https://www.newtis.info/tisv2/a/en/e...ronics/hTzv0Iz

Use this guide if you need to solder the resistors:
https://www.e90post.com/forums/showthread.php?t=872226


XHP:
To finetune with XHP, get a secondary CAS3+. Read your CAS3+ dump, edit VIN to E7x N55 8hp car and write back to new CAS3+. This will be your XHP cas so you can buy, tune and flash XHP on the gearbox. When done, just install original CAS back.

Good luck. Please update your progress in this topic, share experiences and develop this method with us


Big and special thanks to Raimund, Eddie and James for testing this method together with me!

8HP Retrofit Discord: (wip)
https://discord.gg/Y86m3qhq5f

Updates:

6-6-2025: Posted the guide
9-9-2025: Removed the CAS3+ req, because CAS3 also supports EWS4

[Raimund]

Thanks for the help on mine!

[MrDarkArtz]

Should be thanking you! An insane retrofit guide and I can’t wait to get mine going.

[panky]

hi this link not working
https://bmw-az.info/egs/33-bmw-e70-7...eter-file.html

could you please fix this?

[panky]

hi
could you please also mention any 8hp45 transmission PART NUMBER, which can be used on e90 in Australia?

thanks

[alexnaoumov]

Originally Posted by panky

hi
could you please also mention any 8hp45 transmission PART NUMBER, which can be used on e90 in Australia?

thanks

I didn't check partnumbers. I just bought one from an E84 N20 donor. There will be A LOT of part numberes, which will compatible ones. I mentioned in the starter which one you should search. Good luck!

[alexnaoumov]

Originally Posted by panky

hi this link not working
https://bmw-az.info/egs/33-bmw-e70-7...eter-file.html

could you please fix this?

Works for me and others. So sadly can't fix it

[panky]

Originally Posted by alexnaoumov

Works for me and others. So sadly can't fix it

Sadly, not working for me. I tried both Google and Internet Explorer.

[panky]

Originally Posted by alexnaoumov

I didn't check partnumbers. I just bought one from an E84 N20 donor. There will be A LOT of part numberes, which will compatible ones. I mentioned in the starter which one you should search. Good luck!

I think I got one. but very expensive in AUD 3000. But thanks for replying

[panky]

hi

just wondering, for e90, does the engine have to be from e84 n20 engine?

or can I also take transmission from n47 engine e84 ? as the below description

BMW X1 TRANSMISSION AUTO, RWD, DIESEL, 2.0, s18d, N47N/N47T, E84, 07/12-07/15

thanks in advance

[ptpending]

Originally Posted by alexnaoumov

Works for me and others. So sadly can't fix it

there is alternative option as well
https://www.bimmertuningtools.com/product/8hp-isn/

[alexnaoumov]

Originally Posted by panky

hi

just wondering, for e90, does the engine have to be from e84 n20 engine?

or can I also take transmission from n47 engine e84 ? as the below description

BMW X1 TRANSMISSION AUTO, RWD, DIESEL, 2.0, s18d, N47N/N47T, E84, 07/12-07/15

thanks in advance

Not sure, please compare bellhousing and let us know. If it fits, it should work . 8hp EGS is the same in all E-gen cars

[alexnaoumov]

Originally Posted by ptpending

there is alternative option as well
https://www.bimmertuningtools.com/product/8hp-isn/

Indeed, thanks for sharing. This is a very good and probably easier alternative for ISN reset.

[mancing]

I have successfully run 8hp45 on a 2005 E90 320i N46 without replace any modules,There are original modules MV946 JBBF1 FRM1 CAS2，it seems that EWS4 is not necessary.

[MrDarkArtz]

My swap is complete! I’ve had quite a few ups and downs 😂 but my god what a difference it makes. It’s a new car, honestly. I’ve got a few teething issues to sort now, but all in all, this is beyond worth doing for those who haven’t yet. For anyone using the n20 TC and flywheel, check the bolts for the TC. I ordered the lot from BMW direct and they sent the wrong ones out. The n20 (or possibly just e89) used smaller reverse torx ones.

My specs
- 2005 325i n52 silver top euro spec
- FRM3R PL2
- JBE3 M
- MSV80
- CAS3+

Now time to straight out a few bits and work on the cruise control issue and the airbag module

[Beemermane]

Originally Posted by mancing

I have successfully run 8hp45 on a 2005 E90 320i N46 without replace any modules,There are original modules MV946 JBBF1 FRM1 CAS2，it seems that EWS4 is not necessary.

Could you please elaborate in detail?
How did this work with ISN?
Did you just install the transmission, do the wiring and it worked??

[armenh7]

Nice!

[titan.n54]

Originally Posted by panky

hi
could you please also mention any 8hp45 transmission PART NUMBER, which can be used on e90 in Australia?

thanks

Use realoem.com and look for any F3X 20i/28i/35i RWD

[cybmp3]

Originally Posted by MrDarkArtz

My swap is complete! I’ve had quite a few ups and downs 😂 but my god what a difference it makes. It’s a new car, honestly. I’ve got a few teething issues to sort now, but all in all, this is beyond worth doing for those who haven’t yet. For anyone using the n20 TC and flywheel, check the bolts for the TC. I ordered the lot from BMW direct and they sent the wrong ones out. The n20 (or possibly just e89) used smaller reverse torx ones.

My specs
- 2005 325i n52 silver top euro spec
- FRM3R PL2
- JBE3 M
- MSV80
- CAS3+

Now time to straight out a few bits and work on the cruise control issue and the airbag module

Hello, Do you meet a problem with curise($544 or 540)?
Is 8HP45 not compatible with cruise control?

[titan.n54]

Originally Posted by mancing

I have successfully run 8hp45 on a 2005 E90 320i N46 without replace any modules,There are original modules MV946 JBBF1 FRM1 CAS2，it seems that EWS4 is not necessary.

do you have any shadow codes after the swap, due to lack of newer modules?

[JerezN55]

Nice work man!
I did the same thing about 3 months ago!
Some problems are not addressed tho.
I have VTG problems which causes ABS and DSC
Still have the shift interlock code aswell even tho i tried shorting it.
We’ll keep yall updated

[titan.n54]

Originally Posted by JerezN55

Nice work man!
I did the same thing about 3 months ago!
Some problems are not addressed tho.
I have VTG problems which causes ABS and DSC
Still have the shift interlock code aswell even tho i tried shorting it.
We’ll keep yall updated

Did you follow all the steps stated on first post? Upgraded the modules or go with the stock ones?