Auto transmission Troubles????????

[Barney Paull-Edwards]

I was going to ask this on another thread but I think it deserves a new one.
Could somebody explain why there seems to be so many complaints about ZF auto`s??? The same tranny series seems, on other cars, to have a good reputation so whats the design problem?? My next car will be an E30 530TDS and I was not bothered about tranny but as I intend to give it a lot more power, will the auto take the power? The 535d will out-drag an M5 and has auto, so whats the problem??

[shogun]

Hmmh, no trouble on my 4HP24 on the 750 and the Alpina B12. Except changing the front and rear shaft seal, but that should be normal on a car almost 20 years old.
My opinion is that there is no special trouble, you just read on this board about trouble, because only people with probs ask here, but no one starts a thread saying that he has no trouble.
Regular ATF and filter change is also important for a long life of a tranny.

[Ferret]

Barney, I think the problem with these transmissions is not particularly a design fault, but more a lack of oil changes.

If you look at any car that gets regular oil changes in its auto box, you can quite happily see them doing 300k+ miles before a rebuild. I suspect that BMW leaned on ZF to take the boxes slightly out of spec, and fit 'lifetime' oils to them. I further suspect that if you have the oil changed every 50k miles in these boxes, they'll run almost indefinitely.

The guys who own the modern 5's on the other forums have come to the conclusion that if you're going to change the oil, do it before 70k miles - else leave it till the box goes bang totally. If you change the oil after this point, the fresh detergents can dislodge lumps of crud in the system and cause problems...

[Ross]

Nothing wrong with the ZF slushie, it even has a dipstick.

[whiskychaser]

I was going to ask this on another thread but I think it deserves a new one.
Could somebody explain why there seems to be so many complaints about ZF auto`s??? The same tranny series seems, on other cars, to have a good reputation so whats the design problem?? My next car will be an E30 530TDS and I was not bothered about tranny but as I intend to give it a lot more power, will the auto take the power? The 535d will out-drag an M5 and has auto, so whats the problem??

BMW UK have ZF employees inhouse. Have spoken to one. If ZF were that much rubbish BM would have booted them out long ago. As for an auto taking the power, VOLVO and DAF supply trucks with auto boxes. Actually the DAF one is a bit crappy but it doesnt go to pieces after 500k let alone 100k.
There is no dipstick on a lot of ZFs and the fill procedure is a bit lengthy. So I reckon the problem is a lot of owners just dont bother checking the ATF with predictable results. Must admit its the first car I've ever known to have a fill plug in the BOTTOM of the sump.

[Barney Paull-Edwards]

So the conclusion is, they are fine as long as you give them regular oil, ok? What about taking 30% more torque than standard?

[whiskychaser]

So the conclusion is, they are fine as long as you give them regular oil, ok? What about taking 30% more torque than standard?

If the box is in good nick when you get the car and you change oil and filter then it should be fine. As for torque, its in the gearbox code. Mine is a 5HP18 and BM's own code for it is A5S310Z (they are both on the plate)
A= auto
5= 5 speed
S= top speed overdrive (D if direct drive)
310=max input in nm
Z= manuf code (Z=ZF, G=Getrag, R=Hydramatic)

Hope that helps