Thread: ZF4HP22 do it yourself overhaul

Yes using an impact driver makes it easier bought the bits this morning, also going to use the transmission park brake pawl assemble out of the BMW trans mine is worn, the seal kit i got from Alto comes with new screws.

I will leave two screws in so when I turn it over to drop the C & D clutch assembly out it stays behind doing two trans get to try a different method or brain comes up with a better idea after 1st attempt.

At this stage Pedro all the clutch plates are worn past useable now the oil pump is stuffed I have not pulled the suction screen apart but would say it may be blocked up with clutch material causing it to starve of oil and seize I last did that filter at 240K and did drop the oil at 260k to see what came out it was dirty. This was when I ordered the overhaul kit from the states.

I have done some towing with it a 26 foot caravan and my boat plus tool trailer. There was a fair bit of material in the galleries will see what the damage is inside the valve banks expect to see a bit of material in these.

But I will wait till I get the trans together and room on bench the donor trans has come in handy already been swapping bits over and may use the solenoids from it too.

A clutch packs the one on the left is from the hp22 trans also the centre part has a gap all the way round the BMW one is tight all the way round

F clutch this one is right at the rear will slowly work my way to the front both units appear the same and same number of clutches and steels, my kit has all new steels etc the picture is the tool used to compress the spring to get piston retainer out.

Also measuring the clutch packs with the new ones barely any wear you could reuse the old ones and no sign of heat on steels

Here is a pic of one of the steel seals a bit hard to get out with those hooks, no working out pack heights to get correct clearances

Have just found one difference difference one of the steels is a wave type steel must be to give a gradual shift this was on the BMW one the disco ones are all straight so pays to check but easy to swap over as changing steels round to get the clearances on the minimum side of things, this apparently speeds up the shifts.

Where the 4th gear assemble fits into the F clutch pack the splines are not in good condition so again the donor trans to the rescue, apparently this is common with this model ZF.

This is the sprag clutch out of me C D clutch pack it has come apart and chewed up a few parts