I need. to know. how. the replacement bushing and seal goes on the torque converter. or front shaft. of the 2001 330i BMW and wat order

The powertrain control module (PCM) monitors the difference between engine speed and transmission output speed. In D3 drive range with the TCC engaged, the engine speed should closely match the transmission output speed. In D4 drive range, with the TCC engaged, the TCC slip speed should be -20 to +50 RPM.
When the PCM detects excessive TCC slip when the TCC should be engaged, then DTC P0894 sets. DTC P0894 is a type B DTC.

TCC - torque converter clutch
Diagnostic Aids
• Bronze material found in the transmission oil pan may indicate stator shaft bushing wear. If bushing wear is suspected, inspect the stator shaft and the input, turbine, shaft for damage.
• Refer to Symptoms - Automatic Transmission for more information.
Do you have a scan tool ?

Install a scan tool.
Turn ON the ignition, with the engine OFF.
Important: Before clearing the DTC, use the scan tool in order to record the Freeze Frame and Failure Records. Using the Clear Info function erases the Freeze Frame and Failure Records from the PCM.
Record the DTC Freeze Frame and Failure Records.
Clear the DTC.
Important: It may be necessary to allow multiple TCC cycles to occur in order to verify a slipping condition. It may also be necessary to ensure the transmission is warm before performing this step.
Drive the vehicle in 4th gear with the TCC commanded ON.
Does the scan tool TCC Slip Speed measure within the specified range for 7 seconds?
130-800 RPM

Inspect the torque converter clutch (TCC) solenoid valve for the following conditions:
• Internal malfunction, such as sediment or damage
• Damaged seals
• Refer to Torque Converter Clutch Pulse Width Modulation Solenoid, Torque Converter Clutch Solenoid, and Wiring Harness .
Inspect the torque converter clutch pulse width modulation (TCC PWM) solenoid valve for the following conditions:
• Internal malfunction, such as sediment or damage
• Damaged seals
• Refer to Torque Converter Clutch Pulse Width Modulation Solenoid, Torque Converter Clutch Solenoid, and Wiring Harness .
Did you find and correct the condition?

seal installed wrong way round
groove worn in seal surface on axle /shaft
worn bush /failing bearing for shaft not keeping shaft in the center of the seal

Check the hub. You should inspect the old torque converter you are removing for damage to the converter hub that rides in the pump of the transmission. If you find any wear on the hub at all, you should replace both seal and bushing. If you find no wear at all, you may be fine with just a seal replacement. You should at least do one (seal) if not both. (seal & bushing).

Here is a link for further information:

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Thrust bearing failures

Two separate fixes, suggest the first as you can do both easier. Drop drive shaft and starter and remove transmission. The front pump assembly will have to be removed from the transmission and the front bushing and seal can be accessed and replaced. inspect the input shaft to the torque converter to make sure there is no wear. That's on the area where the bushing rides. You can do the same with the rear bushing and seal and output shaft. While you are at it remove the pan and replace the filter. A mess at best but it would be highly advisable.

YOU COULD HAVE A BAD SEAT WERE THE SEAL GOES INTO MAKE SURE THERE IS NO GROOVES OR CRACKS THERE

since tranny out to repair pump seal and bushing have it pressure checked and flushed and install new torque converter at transmission bench build facility.

CODE PO1870 IS TRANSAXLE COMPONENT SLIPPING CONDITIONS.LOOKING AT POSSIBLE CAUSES TRANSMISSION VALVE BODY NEEDS OVERHAUL ALL SHIFT VALVES HAS SEDIMENT DAMAGE OR LEAKING SEALS.THE TORQUE CONVERTER FRONT STATOR SHAFT BUSHING IS WORN THE STATOR ROLLER CLUTCH IS NOT HOLDING.THE TORQUE CONVERTER CLUTCH VALVE STUCK.PUMP TO CASE GASKET LEAKING.THE ORIFICE CUP PLUGS ARE RESTRICTED OR DAMAGED.

This seal is located in the front of the transmission. Its called a front input shaft seal. You will need to drop the transmission and remove the torque converter. Once the converter is off if you look at the shaft protruding from the transmission just at the base of the input shaft you will see this seal.
you can rent a seal remover from you parts store, IE Autozone or Oriely's and rent the seal installer tool. This will insure that you do not damage the seal housing or the seal when installing the new one.
One word of advice would be to take the torque converter to a transmission shop and have it checked before reinstalling it. If it has a worn seal face or has a bad set of blades you would be money ahead to replace it while your doing it the first time and not have to pull it back apart 3 months later.

Dont waste your time and money trying to use a transmission stop leak product, they don't work on large leaks, you say the leak is excessive in this case the you must remove the transmission to access and remove the torque converter, after you have removed the torque converter carefully inspect the torque convert imput shaft for wear and also you will need to visually inspect the transmission front pump bushing for wear also, I have seen it all to often people just replace the seal thinking it was just a seal failure, well more times than not there is a reason for seal more than just the age of the seal, excessive wear on trans pump bushing and torque converter imput shaft is usaully the cause, check and repair those as good practice during this repair unless you just like to do the repair over again for free... also check the torque converter run out, sometime when they are repaired they are welded back together somewhat crooked which will cause it to spin off of a true center, this will cause immediate damage to transmission. Check also your engines crankshaft end play for looseness this can cause wobble which will transfer to transmission causing this problem as well... do the repair thouroughly and who ever does it for you have them check all that I listed and you should get a good repair which will last without issues.... please rate my help thanks...

yes , depending on wheter you talking about torque converter seal or rear engine main seal , on trans if your front pump bushing has excessive wear then it will not seal because the torque converter input shaft will ride on seal more than it is supposed to and also it will not run true, also check TC mounting of flex plate if you flex plate is not centered then it will rotate out of balance and cause leaks and pump damage, if you talking about a rear main engine seal you may have a issue with run out and or bearing wear issues cause seal to not be able to do its job, check all those issues, crank shaft end play as well as up and down play and check rotational run out on TC of trans and pump bushing in trans pump... hope this helps, thanks please rate...