Everything about your ZF automatic transmission issues

I have found this amazing article about the transmission in BMW E90’s so I’m re-posting it here in my blog with updated pictures and part numbers to match ZF 6HP21.

So if you want to maintain your transmission you should read it even if you don’t have any problem in your transmission right now.
Credit goes to : BMW Logic7 site

It applies to all BMW with ZF 6HP19/ 6HP19Z / 6HP21 aka GA6HP19TU
In this post i will be explaining why you have transmission issues like:

-harsh shift 2-1

-not able to shift into park when hot

-weak torque feeling

-transmission faults

All highlighted problems you can experience even on low miles cars less than 70-80k, it depends on at what speeds your car mostly runs. On the highway this transmission will easily last 200-300k miles.

So you hate the way transmission shifts and workshops didn’t find any faults and they told you it is what it is and this is how it is intended to work!

In fact ZF 6HP21 is a very good transmission, powerful, bullet proof pretty much if serviced in time and proper fluid pressure maintained! This transmission is still considered one of the best and has carbon clutches vs cheap paper ones you can find on Japanese cars. But this transmission has very serious and very important weak spots you have to take care of:

-First thing first, check transmission temperatures

If it is higher than 95C, then most likely you have a problem with transmission cooling system or your engine cooling has some leaks causing running it very hot.

Usually high temps indicate following:

1) engine cooling system problem- air bubbles or airlock.

2) if everything is good with cooling system, check your transmission oil cooler- it gets clogged up pretty often and also indicates that some clutches or Torque converter clutch is worn out and that debris clogged oil cooler.
17217536929_335i_only

3) worn out Torque converter clutch slipping overheating transmission fluid.

Your good engine temps are 103-105C and if it climbs to 107-110C in traffic, it means you’ve got a leak :

-lower radiator hose sensor leaking (usually shows a white residue around the sensor).

-valley pan under intake.

-rear cover plate between transmission and engine. Very common after 100k or 8-10 Years.

-coolant tank cracked.

-radiator cap leaking pressure.

-coolant pipe seal leaking.

-other cooling issues.

It is very important to keep temps in specs not only because of few degrees, but because with leaking cooling system lose coolant pressure introducing air in the system, causing uneven cooling and overheating both engine and transmission. Good OEM specs are 103-105 cycle when idling and lower hose should be hot around 60-80C. When you drive it tstat is controlled by ECU therefore it keeps it cool on the freeway.

Easy way to test your cooling system

1)Disconnect aux pump connector assuming aux pump is working (they fail often).

2)Drive your car to warm engine well.

3)Turn on heater on hot but low speed.

4)check if you get hot air from vents for 10 minutes.

5)If after a minute you noticed your heater is not hot anymore, it means you’ve got a leak!.

6)This Engine has self bleeding cooling system, which means you cannot get air pocket if system is well sealed.

So if engine temps are good and transmission still runs hot 100-110, it means heat exchanger is clogged with transmission clutches, Torque Convertor wear and tear dirt. Replace it and check if it got better. This transmission will die quick if temps are not good.

– MECHATRONIC Adapter Seal

This adapter (number 2) usually lasts only 60-70k miles. Replace it every 60k miles even if transmission shifts well. It is very important because it keeps your mechatronic valve body under specified pressure therefore it controls how clutches are pressed! Which means if your gasket is weak your transmission clutches are not pressing well on each other causing premature wear and tear, also transmission pump and TC clutch will be affected.
This square seal also can crack, in this case you will get transmission fail safe errors and even clutches slipping errors, causing very quick transmission death. don’t drive your car if you’re getting any transmission faults, even after restart transmission errors go away for a while, it is not a transmission computer glitch!!!

Mechatronic Seal Adapter late 6HP19 & 6HP21
BMW part number : 24347588724
ZF Part number : 0501 215 783

YES THIS SMALL, CHEAP GASKET CAN DAMAGE YOUR TRANSMISSION PRETTY BAD

-4 Rubber Seals

They are 5,6,7 also controls clutch pressure, but even if they are flattened, pretty bad transmission won’t give you any errors. Its always good idea to replace it- you’ll notice a difference how your transmission shifts.

BMW Part Numbers:
24107536339 x 2
24107536340
24107536341

ZF Part Numbers:
0501 319 279 x 2
0501 319 280
0501 319 281

-SOLENOIDS (Pressure Regulators)

1068_298_046

Yes they go bad and are not simple solenoids you used to know from old school transmissions. Now these are pressure regulators and they do not only work open\close operation, they control pressure and after so many time they get clogged, overheat, etc. So if your transmission temps are good and your transmission shifts hard, it could be your solenoids. Its good idea to replace them every 100k, because they control everything in the transmission. You will be surprised how transmission shifts with new solenoids.Also don’t be scared if you open your transmission and find out that color is not the same- relax it changed color because of temps and age.

Unfortunately ZF does not sell the SOLENOIDS kit, you have to hunt for it in some online sites.
You can see that in the parts catalog:
Solenoid_Kit_6HP21

1068298046_1071030003

1068298046

1068_298_046

and you need to replace the protection foam strip with the solenoids:

1068327241
Protection Foam Strip:
ZF: 1068 327 241

A useful document for replacing the solenoids can be found here:
solenoid_replacment_6hp21.doc

A video I made to replace the solenoids:

-Giubo (FLEX DISC)

26117610061

BMW part number : 26117610061

with:

26117526611

Driveshaft Centering Sleeve / Guide bushings
BMW part number : 26117526611

They usually go bad after BMW lifetime period 60-70k.

Common Symptoms:

a) hard 2-1 shift

b) at stop you can hear clunking when shifting from P-R-D

c) overall transmission shifting quality

Check this amazing article: How To Properly Install Driveshaft Flex Disc (Giubo)

-transmission fluid level

Yes due to leaking oil pan gasket you might loose some fluid. Always check transmission oil pan for leaks and transmission fluid level (use BMW sealed transmission fluid level check procedure).

-Torque converter

tourqe
02/06 – 03/07 ZF: 4168 025 487
01/07 – 08/07 ZF: 4168 025 553

Yes it can go bad just like any clutch, because this transmission engages this clutch very early causing premature wear and tear.it can engage clutch as early as at first gear!! That’s why we get decent mpg from this transmission. In other words it is more like a manual transmission with torque converter working only at very low speeds and low rpm. So I would NOT recommend driving it very aggressively in the city, unless you enjoy paying 4-5k for a new transmission. Don’t forget this transmission handles 300-400hp and some impressive torque. Driving in normal mode, Torque converter can last up to 300k miles!!

most common symptoms of bad clutch:

-sometimes when clutch is very bad it will throw 1721 error clutch slip.

-bad MPG. Without TC clutch your car is still drive-able, but you can feel its very weak even though engine feels strong

-after 4th gear tachometer arrow is not steady

-weak pickups, downshifting when driving uphill

-bad slipping clutch will overheat transmission pump and finally will kill internal transmission parts (clutches, valve body, seals, etc)

You can have your Torque converter rebuilt for around 300$, its not as perfect as new, but decent still.

Its a long list of issues, but if you take care of your transmission every 80-100k miles it pays for itself pretty good. Most important thing for this transmission is correct fluid pressure and temps, other parts like clutches are very durable and made with highest quality standard. Don’t forget the same transmission they still install on newest Bentley, Rolls Royce, Audi, Maserati and other luxury brands. This transmission is way more reliable than Mercedes one or Lexus transmissions.

Fire extinguisher and under seat bracket for BMW E90 335i

I have ordered the bracket used to mount a fire extinguisher on BMW E90 vehicles.

Fire Extinguisher Mounting Bracket (sport seats):
52100408186

If you don’t have (sport seats) then you can use:
52100413021

52100408186

52100408186

I have purchased a portable fire extinguisher:

firestop

Here are the photos:

Note that the none sport seats version will look like this (it is similar to the other bracket but this one is straight shape not curved):

52100413021

52100413021

N54 overhaul

before you post any comments regarding this work, there is no Walnut shell blasting service where I live.

The story started like this:
My car’s oil filter housing was leaking, so I decided to replace the gasket for the oil filter housing:

If you want to do that you will need the gaskets 11427537293 and (11427525335 oil cooled models only)

And it is better to replace the bolts:

11427540759 – 11427540763 – 11427540758 and 11427542983 x 3 and O-Ring for water hose 11537545278

You will need to drain the coolant and 1/2 liter engine oil to top up.

While the mechanic is working on that, I have discovered that the manifold vacuum plastic nipple is broken:

It is a common problem in N54’s manifold, so check your manifold ASAP.

So I have replaced the manifold, the old part number: 11617564678

The new one is: 11617564679
You may see numbers like 756467801 756467802 756467804 printed on it.

The intake valves was full of carbon build ups, So before you post any comments regarding this, there is no Walnut shell blasting service where I live.

my car mileage is 180,000 KM and it was manufactured in September 2006, so 8 years passed.

Later on , I came back to the shop and decided to do an engine overhaul

So here is the engine in the “blue operations room”:

And the empty engine-bay:

Attached to ZF 6HP21 transmission:

The valves and the cylinders after removing the cylinder head:


The ZF 6 speed automatic transmission alone:

The Required Parts:

Parts to open cylinder head for BMW 335i LHD Automatic E90 2007 VB71 Sedan European GCC specs (Manufactured 9/2006) (the job was done in Dec 2014 with 180,000 KM at that time):

Valve Stem Seal Kit – Intake
11340034068


———-
Valve Seal Repair Kit – Exhaust
11340035853


———-
Cylinder Head Gasket
11127557265


———-
Cylinder Head Gasket Set
11127572758

The set includes:

11127565286 Valve Cover Gasket

11317534251 Gasket Ring

11367507729 (2 Pieces) O-ring

11367548459 (2 Pieces) VANOS Solenoid Valve Sealing Gasket set

11427537293 Oil Filter Housing Gasket

11537545278 O-ring

11617547242 Manifold Set of profile gaskets

11627558906 Gasket ring (6 Pieces)

12141748398 O-ring

13547522361 Throttle Body Gasket
Only applies to
13 54 7 556 118 up to Modification Index 03
13 54 7 556 119 up to Modification Index 05

13547582931 Throttle Body Gasket
Only applies to
13 54 7 556 118 starting at Modification Index 04
13 54 7 556 119 starting with Modification Index 06

18307553603 Down-pipe Exhaust Gasket (2 Pieces)

End of Cylinder Head Gasket Set
———-
Gasket (oil cooled models only)
11427525335


———-
Cylinder Head Bolts – Set (one time use only)
11127574303


———-
Oil Pan Gasket
11137548031


———-
Turbo Oil Line Gasket No.7
11422246091 x 2



———-
O-Ring No.5
Used to seal the oil and water lines for the turbochargers, 8 required for the coolant lines, 4 for the oil lines
11427558936 x 12




———-
O-Ring – No.6
Used to seal the turbo oil pipes, 2 required
11427563453 x 2



———-
Radiator Hose Gasket No.4
The gasket that seals the junction between the engine block and radiator hose
11537545302



———-
Turbo to Down-pipe Exhaust Gasket No.3 Gasket that is between the turbo and down pipes, 2 required
18307553601 X 2


———-
V-Band Exhaust Clamp No.4
11657620508 X 2



———-
PUSH ROD (Lifter) (you need to replace those ONLY if you have high mileage like me)
11337548690 x 24



———-
Intercooler Pipe Seal No.19
11617791469


———-
Intercooler Piping Seal-Right No.3
11617791470


———-
Intercooler Pipe O-Ring No.2
13717568030 X 2



———-
Rear Intake Pipe Gasket No.10
Gasket in between upper and lower intake hoses
13717568029


———-
Front Gasket Ring No.2
13712247398



———-
Crankshaft Seal – Front No.2
11117547842


———-
Crankshaft Seal – Rear No.1
11117587168



———-
Collar Screw No.13
Holds the camshaft gear to the camshaft. 2 per vehicle.
11367524954 x 2


———-
Timing Chain Tensioner and Guide Rail
11317542837


———-
Slide Rail
11317516093


———-

Now the transmission parts ( I had a leak in my transmission):
Gear_Leak_335i

Transfer Case Seal No.9
24317519352

O-RING No.10
24317536355

O-RING No.12
24201217321

Transmission Sealing Sleeve
BMW: 24347588725
ZF: 0501 216 272

Transmission Pan Gasket (you don’t need to buy it if you will replace the transmission filter/pan)
BMW: 24117571235
ZF: 0501 323 156

You may want to change the transmission filter/pan if you have a leak (it comes with the above sealing sleeve)
BMW: 24152333907
ZF: 0501 216 244
ZF: 0501 220 297

Oil Pan Screws for “Plastic” Oil Pan (24)
BMW:24117552108
ZF:0736 101 486
24117552108

Transmission Oil pipe O-RING No.3
17227581147 x 2


———-
1 out of 6 of my spark plugs was darker than the others, this indicates bad injector.

Now my injectors are the original old ones, never been replaced before, I couldn’t just replace only the bad injector because it is recommended to replace all six instead of mixing and matching. The index number is found on the head of the injector after the BMW part number. Example: 1353 7537317-10 “10” is the index number. With an index of 11 or greater, injectors may be replaced individually with a new injector. If the index is 10 or less, all 6 injectors in an inline-6 engine must be replaced. Injectors with index 10 and lower have a different calibration and construction than injectors with index 11 and higher.
Also the new injectors needs to be coded into the ECU, it is very important to write down all the information printed on the injector and on which cylinder before installing.



These are my injectors values ONLY. Yours will be something else.

These are my injectors values ONLY.
Yours will be something else.

The new part number for the injector:
13538616079 X 6 (you will see this number printed on it 13537585261)
13538616079
———-
Decoupling Element for fuel injector
13537564751 x 6

———-
Spark Plugs
12120037244 X 6
or
BOSCH ZGR6STE2 X 6
ZGR6STE2
———-
Low Pressure Fuel Sensor No.7 (no need to replace this if you don’t have a faulty sensor like the one in my car)
13537614317 or “13537545725 Pipe with (13537614317 attached)” or the new one 13537622751 (Pipe with new sensor 13537622231 attached)

13537614317

13537614317

13537545725

13537545725

13537622231

13537622231

———-
Oil and Filter Oil: 5W-40 or 0W-40 6.5 liters
Filter: 11427566327 Oil: 83210144456 x 7(0W-40)
———-
Anti-Freeze coolant
83512355290 x 2
———-
Hydraulic Power Steering Fluid
83290429576 x 2
———-
Automatic transmission fluid 10L
83222220445 (1L New)
or
83222305396 (1L old)
or
83220142516 (comes in 20L)
or
ZF Lifeguard fluid 6 (1L) (ZF No. S671 090 255)

It is a 50 hours job! So think twice before you decide to open your BMW cylinder head.