Firstfives.org

Ive been trying to figure out what is the underlying issue with my 81 528i auto box

its a ZF 3HP22 unit
engine starts - and can forward or reverse okay

then if drive for like say 3 mins - - changing up and down gears AOK - then - all suddenly all drive to wheels stops. If I turn engine off - wait a few minutes- then start again can drive for 5 mins, before looses drive to wheels again.

I am wondering if anyone could have a look at this ZF 3HP22 manual

http://peugeot505.info/files/manuals/505_3hp22.pdf

and tell me what part I need to have a look at.

my suspicion is that its the hydraulic block - or maybe the pump - but would a pump stop working after a few minutes?


I complied a drawing sheet from the manual to assist.



Ive attempted to remove the hydraulic block, but 3 of the torx head screws I managed to strip!
so I removed the rear plate instead and checked out the pistons -(no 14 - 20 ) I'm not sure but I think the No 13 main pressure valve might be stuck (not sliding freely) - unless there is something that is meant to stop it of from coming out - the two springs holding it in are real stiff!

If I could I would have left the Hydraulic block assembly fixed to the transmission and just remove the 2 cover plates to get at the pistons, but I couldn't get a front plate off due to interferenec with filler hose - so I removed the whole assembly .

So now that the assembly is out, began to dismantle it.

The block has 2 halves with 2 end plates and an extra part bolted on it.

ancillary part removed







It looked like I needed to remove the pistons before separating the 2 halves.
I unscrewed the cover plates and removed the springs, pistons and caps. taking photos of each part as it was removed
Then I unscrewed the last 2 screws which kept the 2 halves together.


The separating plate and gasket were quite stuck to one half, I'm not too keen on separating the plate and gasket - so left them as is and gave all the rest a good clean.

block separated into 2 halves


]

There was a bit of muck in a few channels and on the outer casing, which brake cleaner, rag and air spray eventually got out. I did all the separating and cleaning in a large laundry bucket

Here is some photos of the parts.

separated the 2 halves of the hydraulic block



the 2 ends of the block has 2 clover plates , which cap the end of all the pistons.





there were 3 very small "caps"( about 5mm diameter with a slight cupping and centre hole ) which fell out, thankfully I heard them hit the tub- hopefully I got the right position for them.

some of the pistons/valves have holding clips, which I recorded how they were orientated






The repair manual has these indicated - here is my note sheet a made on it.

Once all clean up - the repair manual says to reassemble in reverse order.

I basically started at the bottom ( of the drawing ) and worked my way up to the top - leaving the main pressure valve+ converter pressure valve (no 13 + 14) - as I was not too sure how that was to go, as it consisted of 2 valves, 2 springs and a sleeve. When I dismantled it - it came out differently to the drawing.

photo of disassembly
first out came the springs


then the main pressure valve with sleeve



Now back to reassembly.

Any way, I got all the other valves, spring and pistons in , plus their required 3 clips and 3 reducing cups. I checked the movement of all these and they seemed free enough.


The springs need a bit of pressure to clamp the cover shut - I ended up using a clamp to hold it whilst I screwed in the screws.


I then bolted the other half of the assembly -leaving the main pressure valve to the very end.


I installed the main pressure valve according to the drawing - although the drawings does not seem to show a valve that fits inside the sleeve (no 14) I hope it works out okay.

Here are the parts laid out ( main valve not shown as its inside the body already.

sleeve, converter valve, outer spring, inner spring ( + main pressure valve - not visible, as I'v already inserted into the body)


put together


looking at main valve inside body




Then I installed cover plate. Due to the double springs - the cover plate takes alot of force to get the springs to compress so the screws can then be screwed in.





Once I was happy with that, I installed the external parts.



Its now ready to be reinstalled to the transmission

I need to get some more bolts though as some of them didn't survive very well the chisel head method of extraction! M6 x 80mm I think they are.



Reassembly took me maybe 70 mins - as did is slowly and double checked an redid a few valves as I got the clips in the wrong slot - (which prevented the valve from moving.)

I just found this valve body overhaul page for the ZF 4HP22EH which maybe helpful to understand these things

http://twrite.org/shogunnew/files/jason ... ebody.html

Having now looked at this, I wonder if I have the cups orientated correctly and if the checkballs need to be checked? Its hard to tell in the Peugot service manual I have.

Ive reinstalled the valve body into the car and taken it for a couple of drives - seems to engage 1 an 2nd sorta okay - but only at high revs, doesn't want to go onto 3rd yet - I am wondering if the fluid is bit low.

But it does take off and rev ( to 5500) in 1st wonderfully now!

Couldn't drive for long as the engine steamed up!

reverse is -- erre --- ordinary to almost non existent - ie real slow to engage - but goes once going - sort of .

Anybody got any idea or drawing of the accumulator cup orientation for the 3HP22

I think I may have reassembeld them in the wrong orientation (all are down).

I found these 2 images of a 4HP22 hydraulic block, but the layout is quite different, I dont know what the passages relate to, to transfer that design intent to the the 3HP22.

Dosn't look like a lot of Fivers have had that auto trans apart to help you out? Ever thought of switching to a 4 or 5 spd manual trans? Are there still E12's at the wreckers in OZ?

The ZF3HP22 is the most common A/T in E12s, but not many people work on them themselves.

This is the best I can do, image wise. I do have a 62 page manual on 3HP22's for Peugeots that I could email to you if you want, I obviously can't post all 62 pages. I doubt there would be much difference in assembly, but I don't really know.

thanks Mike,
I do already have the Peugot 3HP22 workshop manual.

That scanned image is the one I cant work out exactly what the orientation of the pressure caps is ( No9)

whats your take on them ( no 9)
this is my guess.
on left side
1 (in line with No 16) - down
2 (just above No 17))- down



on right side
3 (just above No 22) - up






hmm, I might have put them in the wrong way
chow

Gary

I just found a photo I took whilst dismantling - Duurrr which seems to indicate the cups and their orientation.

I also have a photo which indicates the position of the checkballs in the upper half.



here is rotated and compared to the diagram



They all appear to be facing up.

I looked at my photos of the reinstallation - and I seem to have installed them all facing upwards ! fancy that.

garyinwestoz wrote: Tue Mar 09, 2021 3:22 am
I looked at my photos of the reinstallation - and I seem to have installed them all facing upwards ! fancy that.

As an amateur who has been inside an A/T just a couple of times, you can't take too many pictures of the process or make too many notes.

Gary. Good work here. Great to see someone working on one of these. Hope it all works out for you

Like Mike W. said, you cannot take enough pictures when dismantling automatics. This is usually work for automatic transmission experts.

If all else fails try Clifford's Automatic Transmissions, a place in your neck of the woods. I remember someone on First Fives mentioning them years ago concerning a rebuild of the ZF 3HP 22 automatic, I remember because their initials made the word CAT, and their logo was a cat Apparently they did a great job, at a very reasonable price, with a warranty, and they had a very good name. Contact details below:

Clifford's Automatic Transmissions CAT

Yeah, automatics are a different story to manual transmissions, really skilled work. Worse than a/c.

well

the last drive I took, I added more fluid and well- it changed into the 3rd gear and was nice an smoothish - boy 20-80 in about 7 secs - seemed effortless.

however,,

when I got back to the workshop and went to go in reverse - urr nothing.

I turned engine off

let is sit for a 30 sec s or so restarted and reverse engaged and I managed to part it back under cover.

hmmm - need to relook at the book again!