two ZF 4HP22 repairs

[Joe]

Thanks.

Most helpful, got my haynes manual in the post, so as soon as it arrives we begin!

Thanks again.

[MicahO]

Great post - incredible information. I don't think I'll ever venture in there, but for anyone who is getting screwed by a tranny shop - here's the guide!

Wrong tranny, but about 2 weeks ago, the tranny on my former 525iT went out. I've avoided talking to anyone bimmer related for a while, I had this though of buying the car back (sold it to my neice's fiancee) and sending it out to Brett Anderson. I really didn't need any of you merry band of misfits convincing me that it would be a great idea!!!





--Micah

[winfred]

i was lucky on my 535, it has a factory reman in it that's not even dirty yet, if i had to guess it has 50-60k on it (i've put about 26k in two years), if i have it long enough ill get into it, they never put the improved seals in the factory trannys (if you order a rebuild kit it comes with the steel seals) the sweetest zf i've driven is in moms 80k mile 90 325isa, if your easy on the throttle you don't even feel it shift, if you ass down on it, it chirps 2nd and down shifts nicely. as for rebuilds all but the best shops are going to reuse a lot of the hard parts, which is not too bad, but the best shops are going to charge about the same $ as the dealer for a zf reman which id rather have, we got one for a friend of the shop for his e32 735, if i remember right it was about $1200

who did the neutral slams. See what you mean. Tranny work is tough...both in pulling the trans, repairing them and then seeing if they stay together after the fact....why Kirt Koeller bought a dyno for his shop so he could test everything he rebuilt...a lot of steps involved...best to check one's work if possible and a dyno helps.
Have you ever had the autobox apart on your 535i?
George

[Unregistered]

My '89 525iA (224,000 km) has been sitting motionless since early Dec 2003 with tranny problems. Can you comment on my symptoms matching your fix? I drove the car about 20 miles around town, then at the bottom of a gully with steep climbs either way out it stopped making headway. Having heard of this problem with the early E34's I coasted backwards up a driveway and turned around thinking that I could drive the remaining half-mile home in reverse. However, left it parked there because reverse was like driving with the hand brake on. Lots of resistance, whereas forward just didn't grab at all. I left it there for four days until I could borrow a 4wd truck on the weekend. When I went back for the car it drove fine again, at least the last half-mile back home. Reversing it up my driveway it again developed the heavy resistance after reversing about 30 feet.

It's the problem in reverse that has me worried that the standard fix, your beautifully documented procedure, isn't going to go deep enough to get me back on the road again.

Thanks for your feedback...

Bill K. in Sydney, Australia

[winfred]

could be a fluid problem, like a clogged filter. generally when the clutches crap, it's toast

[George M]

so you are saying Winfred that for your money you would prefer a factory remanufactured ZF tranny sold from a BMW dealership? versus a trans from a good rebuilder...because the no. of parts changed/seals replaced etc. will be greater with a remanufactured trans?
Thanks,
George

[TimGinCentralNJ]

...in the ZF's beginning in around mid/late-'88 in the ZF-HP422E (I believe was the model). The story I read indicated BMW (although never admitting this issue was worthy of a full "recall", of course) came up with a retrofit valve of some sort to allieviate the well-known blown clutch pack issue occuring when the tranny was revved for extended periods in "N" or "P". This valve was later incorporated into the '88 and later ZF-HP line of trannies.

Is my info way off base? Are we talking about the same problem? (I haven't had coffee yet--pls be gentle with me.)

Thanks for posting this info...always wanted to see the "inner-workings" of this issue...and having it well-narrated helps tremendously, too.

Rgds,
Tim G.
'91 535iM
ex-'91 535iA with ZF-HP422 (stolen, recovered & scrapped)

[George M]

follow up question...you show the A-clutch pack repair/replacement...how about the other 3 clutch packs? In your experience, do these ever seem to fail or is it almost always the infamous A-clutch and the other clutches never experience any overpressurization and therefore by comparison go much bigger miles?
Thanks,
George

[winfred]

if they fixed it, i've not seen it i have done them through the last of the zf's on 92-93 m30s, and if you get the big rebuild kit it comes with the steel seals, the teflon seals are a aftermarket thing. as for rebuilds, for the same money ill take a factory reman over a indy, unless the indy is something special, i look at it like ac compressors, a good 1/2 of the remans on the market are not worth the box they came in, but factory units have the best record for out living the warranty by a good amount.
one quick and ugly test i do, get the back of the car off the ground and let it run in neutral, see if the tires spin more then a little, a real good one won't, a avarage one barly spins, and a turd hauls ass and is hard to stop with your hand

[winfred]

george i forgot your 2nd q, i've gone past 2nd a few times looking around and the clutches are hardly touched, and are still a light tan, when 1st blows up bad ill toss some 2nd clutches in for safety, because 1st gets real hot. i think a-clutch soaks up all of the abuse and saves the rest of the unit, about the only other failure i happen upon some abused trannys will cough up their planitary gears, at which point i sell them a used tranny or if i have a good case (from 2nd back) build that