Soon I am going to have a go at rebuilding the valve body in my 535i. So I though I would get some practice rebuilding the one out of my old 525i first. As that car was written off by a truck whilst parked outside my house last year, the ZF 4HP22 from it, is, shall we say "expendable". The 525i was an '89 model with a fully hydraulic version of the trans, so there are some differences between it and the one in the 535i which is the later 4 solenoid, 7 pin, electronic/hydraulic (EH) version. There are however more than enough similarities to make this a worthwhile excercise.

So after a lot of study I finally bit the bullet and started pulling the thing apart today. Cleaned up all the parts and am planning to leave it for a few days to see if the systems I have in place allow me to put everything back in the right place.

So far I am happy with the results. It's certainly made me more confident, ready to tackle the 535i. These things are not as complex as you first fear when you start your research.

Photos below:


4HP22 with pan, filter, valvebody, torque converter, and bellhousing removed.


All the cleaned bits of the valve body laid out, note the tub of degreaser for cleaning parts.


A few of the ancillery valve body components all nice and shiny, checkballs and cups in place ready for assembly.


Main valve body plate, filter and o-ring.


Main valve body, without checkballs and cups.


All the bolts are placed in a "map" of where they came from. Checkballs and cups are taped to a page of the ATSG manual in their respective positions.


**** Days Pass ****

The weather was pretty crap today so I decided to continue with my valve body rebuild. I would like to document more of the process with photos, unfortunately I don't want to handle my DSLR with ATF soaked hands. So you kind of jump straight to the endgame. When I do the 535i I think I will organise an assistant to act as a second pair of eyes and photographer.

Photos below:


Rebuild complete. It's a really good idea to have a comfortable work position, and stay organised! There are so many tiny little pieces to misplace and or mixup. It has also been pointed out to me that the area should remain free of distraction.


The 535i patiently waiting for her turn. I think she wants in out of the rain.


The bolts remaining are those that mate the valve body to rest of the transmission. I used vaseline to hold checkballs, cups, springs, spacers, shafts, and plugs in place during assembly.


This is the top of the reassembled valve body, the side that mates to the transmission proper.


This is the bottom, pretty much all that goes here is the filter.


Success! Reconnected to the transmission, and no mystery bits left over.