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Thread: What is it with ZF transmissions?

  1. #1
    Join Date
    Oct 2010
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    1999 E38 740i

    What is it with ZF transmissions?

    I currently have an E38 740i and love it, but these are noted for transmission failures, in particular the 5HP24 and not just on high mileage vehicles.

    I am looking to sell it and maybe get a 550i. Good, I thought, ZF will have moved on and incorporated improvements in the later 6HP26. My research shows a common theme of transmission failures, again not always on high mileage vehicles. Same old, same old all over again!

    I realise this is not going to be considered a problem for those who buy new vehicles, after all they have warranties, but the failures often experienced by those who buy second hand in no small way contributes to the terrible depreciation that the buyers of new cars have to accept.

    Modern vehicles have levels of reliability for most components only dreamed about 40 years ago. It is disappointing that transmissions in these so called quality cars cant be counted on to the same degree.

  2. #2
    Join Date
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    Japan
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    11/88 E32 750iL+98 E36M3
    The ZF automatic transmissions are quite reliable. Important is that you change the ATF and ATF filter based on ZF recommendations.

    As far as I know there was only 1 recall with a very small number of affected BMW E38 5HP24: 1999 BMW 740IA Recall ID from NHTSA: 99V005000 Auto Recall Date: 19990104 Vehicle Component: POWER TRAIN:AUTOMATIC TRANSMISSION
    Estimated Vehicles Affected: 249
    1999 BMW 740IA Defect Summary: VEHICLE DESCRIPTION: PASSENGER VEHICLES EQUIPPED WITH A 5HP24 AUTOMATIC TRANSMISSION. PREMATURE WEAR OF THE RING GEAR CAN OCCUR, LEADING TO THE LOSS OF 1ST, 2ND, 3RD, AND REVERSE GEARS.
    Defect Consequence: IF THIS PROBLEM OCCURS, THE CAR MAY NO LONGER OPERATE IN REVERSE, 1ST, 2ND, OR 3RD GEARS. Remedy: DEALERS WILL REPLACE THE AUTOMATIC TRANSMISSION.

    Major items which could cause a problem:
    Cracked “A Clutch” Clip
    A circlip in the A clutch pack cracks, typically causing a delay going into drive, usually followed by a harsh thud into gear and transmission failsafe mode activation. If caught early enough, simply replacing the clip is a feasible repair, however it is often necessary to replace the entire A clutch, and even overhaul the transmission in cases where the problem has been left for some time.

    Reverse Piston Failure
    The molded piston that applies reverse gear has a tendency to fail on the ZF5HP24 automatic transmission, losing a portion of the rubber that forms the seal. This causes reverse gear to partially or wholly fail to apply, usually resulting in a loss of reverse gear. As with the above A clutch failure, if caught early enough it may be sufficient to just replace the faulty piston, however leaving the problem can (and usually will) cause other problems within the transmission.

    Cracked Hydraulic Control Unit
    Specifically in Jaguar’s, the ZF5HP24’s hydraulic control unit (valve body) has a tendency to crack along a portion of the casting. This causes a range of problems with the transmission’s shifting, from slipping and flaring into gear, to erratic shifting. The valve body can be repaired/replaced, however this problem should be repaired as soon as possible to avoid further damage to the transmission.

    here nicely explained https://www.youtube.com/watch?v=DsQqpkC8Xs4
    Shogun tricks and tips for the E32 series are HERE!

  3. #3
    Join Date
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    2020 Mercedes S560
    Quote Originally Posted by Grantnz View Post
    I currently have an E38 740i and love it, but these are noted for transmission failures, in particular the 5HP24 and not just on high mileage vehicles.

    I am looking to sell it and maybe get a 550i. Good, I thought, ZF will have moved on and incorporated improvements in the later 6HP26. My research shows a common theme of transmission failures, again not always on high mileage vehicles. Same old, same old all over again!

    I realise this is not going to be considered a problem for those who buy new vehicles, after all they have warranties, but the failures often experienced by those who buy second hand in no small way contributes to the terrible depreciation that the buyers of new cars have to accept.

    Modern vehicles have levels of reliability for most components only dreamed about 40 years ago. It is disappointing that transmissions in these so called quality cars cant be counted on to the same degree.
    My 550 had a total transmission failure at 22K miles.

    Never again, BMW replaced it and I sold that car quick. The Audi salesman was pissed when I told him I would not buy another car with a ZF transmission. The 5 series forum is littered with these threads.

    Best of luck.

  4. #4
    Join Date
    Jun 2005
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    New England
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    25,402
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    F90 M5; E36 M3 Turbo
    I think the newer ZF 6 speeds like in our 08 E61 535xi are great. A 22k mile failure is not common from what I have read. Mostly I read of solenoid issues in older 6 speeds and my guess is that these trans were not serviced. They don’t need much servicing. I changed the pan/filter, fluid and mechatronic sleeve as preventative maintenance at 90k.

    The newer 8 speed is an even better trans and is found in many cars. It is well proven.

    These more modern autos shift as fast or faster than a good manual trans driver and get better mpg.

    I do agree that a 20 year old 5 speed auto is likely to need some expensive work. Not sure how the newer ones will do with age and mileage, but something to be concerned about in the future since auto trans rebuilds are expensive and no one likes $4k repair bills.
    Last edited by pbonsalb; 03-28-2018 at 07:49 AM.

  5. #5
    Join Date
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    McKean township Pennsylva
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    1999 M3 , 1999 328is
    The reputation from the 5 speed ZFs in the e38s comes from the fact that they were supposed to have a, "life time fill" of transmission fluid. Any tribologist (lubricant engineer) will tell you that that isn't a great idea. A BMW dealer wont touch the transmissions in those cars usually, they will only sell you a replacement if you are honestly having issues with them.

    Oddly the large majority of e38 "TRANS-FAIL-SAFE" messages come from low voltage due to a dead battery or alternator. As soon as that is remedied the transmission will work again as intended.

    From personal experience. My family has owned two e38s throughout the last 16 years. Never once have we had any transmission problems and never once have we serviced or done a fluid change. The first one had 168k miles on it when we sold it, it worked perfectly. The current one has 120k miles and shifts smooth as it ever has.

    I understand that the new ZF 8 speed is basically the industry leading transmission. Just about everyone is using is and it is even displacing many fancier dual clutch transmissions.
    Current fleet:
    1999 BMW e36 M3
    1999 BMW e36 328is with rotary valve engine head
    1999 Oldsmobile Eighty Eight
    1990 Jeep Comanche Eliminator
    1962 Austin Healey Sprite

  6. #6
    Join Date
    Jul 2011
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    Arlington, VA
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    2018 BMW M240i
    “Lifetime fluids” was a marketing ploy, and not a maintenance philosophy.

  7. #7
    Join Date
    Jan 2016
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    Ca
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    2001 525it
    The newer trans we see faults for clutch pack E

  8. #8
    Join Date
    Jun 2006
    Location
    São Paulo, Brazil
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    598
    My Cars
    Euro Bimmers, Volvo, Citroën Dakar, GTi VR6....
    I have a ZF 6hp26 on my RR Vogue Supercharger, I has a leak in the torque converter and transmission was slipping a lot from 3rd to 4th. I completed the oil, it was missing 2 liters, and the problem was almost solved (90%). Improved a lot, like I said, but is still slipping just a little sometimes, I guess (and hope), its because the leak is not fixed yet. I'm not driving the car as i'm waiting to fix this. I read it happens sometimes with this car, not sure if this transmission is so reliable. The car has 400hp and its heavy...
    BMW Car Club Brasil council member.

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