ZF 3HP22 - goes then stops after 5 mins

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Location: perth, australia

ZF 3HP22 - goes then stops after 5 mins

Post by garyinwestoz » Sun Jun 21, 2020 10:23 am

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


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!
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