ZF6HP21X Teardown
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- เผยแพร่เมื่อ 10 ก.พ. 2025
- In this video, i tear down a ZF6HP21X out of a 5 series BMW, had some codes present for A clutch and E clutch. Car had a big delay in drive, found the A and E clutches in very bad shape. Got it fixed up nice and the trans worked real nice. Thanks for watching, Please like and subscribe.
Hi Gary, I spoke to you a while back when I rebuilt my 6hp21x. My b rebuild was successful. Been driving car for almost a year but now when trans gets to temp everyone once a while my tcc slips only in 3rd gear at low rpm while accelerating but never any other gear. I do have a delay while trans is cold from 2nd to3rd,
I really enjoy your vids. Auto trans are so interesting.
Manual Master Race
6HP21 cores can be found for not too high of a price. I am hoping 21/21X A/E pistons/drums/etc are interchangeable. Do you know if that ever had service, did you check the production date on the pan? I would think it had not been serviced to look that bad. Once again you are the man Gary! You are the transmission man, @Tasos Moschatos is the euro engine builder man. You two are the best, ❤️❤️❤️ watching you two work!
I believe they are, pretty much the same trans except for the output shaft
Great video. Thank you Gary.
Thanks Kevin
Nice video Gary! What would have caused that? Bad maintenance? Oil too old? Solenoids shifting bad ? I guess hi temperature fried the clutches and broke the steel plate. Have a good sunday buddy!
The dealer says these are "lifetime fluid" the problem is the filter is not lifetime nor the fluid. I asked if Gary checked the production date on the pan to see if it was original. I only work on BMWs and I take pics of all the parts I take off and note the production date to inform the customer, and then pics of the new part production date.
@@igotaction for the 6hp19 is 80.000km fluid and filter. Or 8 years. Thanks for the reply
Great vidéo Gary ,and what about the clutches of gen 1 (6hp19) and gen2 (6hp21) they are the same or not ?
there is different kinds of generations. there is 2 generations of the 6hp21, 1st and 2nd gen. the way u tell is the ways he mentioned or just go by years, 07 and below gen 1 08+ gen 2
so 6hp19 is irrelevant completely
Great video ! I have the zf 8hp45x in the 2017 vw amarok . Can you please tell me if you recomend valvoline maxlife oil for this transmission? It has 50k miles and I'm thinking to do the service soon . Slow traffic where I live. Thanks
I haven't used anything other than lifegaurd 8 in these transmissions , not sure how that fluid will work
Hi Gary!
I have the same transmission, only that it's on a E83.
Issue is that when cold, at a stoplight, if i stay like 20-30 sec with the foot on the brake, when i release it to slowly start moving, it's like it freezes for a half of a second and then bam, moves but like someone hit me in the back o the car.
Oil has been changed, pan, tube sleeves, square gasket, zip kit and original ZF solenoids for the mechatronic.
Adaptations done as ZF requires. No errors on the tranny.
Clutch B filling pressure seems odd a bit, -301 mbar.
Any suggestions?
Many thanks for any information
PS. I forgot to mention, if i put the car in manual mode, M1, it's nor doing that anymore. But as long as the car is cold, it shifts a little bad , a liitle bit too long time between shifts and a bit a flare between the first gears!
I'd like to know if it was serviced on a regular basis, looks like burnt fluid and burnt clutches. Fluid and filters are cheaper than a rebuild.
Probably was not, BMW says it's a lifetime fill so probably never changed it
@@GaryFerraro How much do you charge to rebuild my 6L90 automatic transmission? Here in Atlanta a workshop specializing in automatic transmission charges 800 dollars just to make the diagnoses and it's a fair price because they're professionals automatic transmission specialists like you Gary.
@@scottthompson8642 Wow, I offer a free check, if i have to look further i may charge 3-400 diag time. How much are they charging to rebuild your transmission
@@GaryFerraro It's a fair price.You should charge that amount of 800 dollars just to make the diagnoses because you need to value your workmanship.
@@GaryFerraro Well they charge 8000 dollars for labor alone but their work is professional,technical and very well done.It's a fair price.
I suspect how it was driven played a role. If the driver is like many drivers in N.Cal, he treats the space between stop lights like it's Watkins Glen.
Hello Gary, I have a question. I just rebuilt my 6hp21x. New clutches and bushings along with some shaft sealing rings. I rebuilt the valve body(my second one, first was my e66 valve body). To be transparent I did not replace solenoids. I am getting ratio monitoring clutch A 4f81 and ratio monitoring gearshift 5-4 along with 4f91 ratio monitoring clutch A-D. Does this sound electrical or like the solenoids? I would hate to pull tranny again although I think it would go smooth right since I did it recently. Thank for your attention.
First, your sure its full of fluid? Bridge seal is new? What was original problem?
Yes new bridge seal and tube seals. I bought it with bad tranny. Thought a simple fix would get it. I removed tranny and found e drum clutches burned and a couple stuck together.i did fluid fill same as i had done a million times with the e66 lol. I am going to check again when the rain stops here and makes sure it trickles out while running. Also manual shift does not work. I move shifter over then it dings and the shifter picture pops up.
@ I was able to check fluid and it was a little. Got it topped off and it did take off better and drove about 1/2-3/4 of a mile and went into limp mode and would not move. I turned vehicle off and on to get it going again but take off was sluggish and hesitant. Did this two more time 30-45sec apart then did better getting it back home. Codes 4f81 and 4f8d. I’m thinking maybe solenoids. What’s your take?
It ended up being solenoids. I bought a new set and replaced them. I noticed most of the screens on the old ones were clogged with clutch debris the the burned clothes I replaced. I guess some debris was left behind.
Hi Gary,
I watched couple of your videos on the ZF transmissions and they are a great learning material.
I'm trying to diagnose and fix issues on my transmission.
There's a slip on higher RPM from 4th to 5th. Sometimes 4F8A pops up after that happens.
I did rebuild the valve body (dampers, solenoids, plate) and it helped a little bit. I did reset the adaptations and did an adaptations drive.
But now I have a bigger issue - when the transmission is cold there's a big jerk when going from 1st-2nd and 3rd-2nd. When it gets to working temperature it goes away a little bit.
Any ideas what might have gone wrong? Could it be that I messed up rebuild of the valve body or it just showed other mechanical issues?
Your first problem with the slip in the higher rpm sounds like a rear stator bushing. @nd problem may be something with adaptions, are there codes present? adapts will not work if codes are present
@GaryFerraro No codes are present and I did the adaption drive as thorough as I could.
I'm wondering if it may be the A clutch plates?
I'll probably do a full rebuild and I'm trying to order parts in advance to get it up and running asap. 🙂
@@bananeq666 You may have a problem with the C clutch which is on in 2nd and 6th, did you have this problem after resetting the adapts
Hi! Please tell me The friction discs în The 6hp26x are The same as 6hp26? Thank you! Îs The same transmision except The output shaft?
yes sir the garage man already removed valve body and removed the color valve and he lost some one my plan to but new kit but what color 6hp21 f02
If any of your clutches are burnt, do you recommend replacing that specific clutch set or the whole transmission from ZF?
Depends on milage, you can get a friction module which is all the clutches for the trans, if low mileage you can replace whats bad
oh wow! looks easier than i thought (til i actually attempt this) hah!
Gary, how would you compare the ZF 6HP's to the MB 722.6 and 722.9 in terms of strength, engineering, etc? Overall do you think the ZF units or the MB units are better?
I like the ZF units, both are engineered very good , on the ZF units only really see common issues, on the 722.6 and 9 they have converter issues, pumps go bad all the time as well as common problems
@@GaryFerraro Yeah I have limited experience with the ZF’s but it seems like you might be right. It seems like the only advantages the MB boxes might have are being a little more compact and easier to disassemble
If a drum is burned up and only discolored but there is no physical damage, it is ok to reuse it?
sure, just clean it up good and make sure the steel plates move ok inside the drum
@@GaryFerraro Thank you. Will do.
hows ist a cost repair cluch drom and spreag
Gary, do you have a link for parts supplier in EU?
how do you know which is the problem the clutches or the solenoid ,got code 4f81 and 4f84 A ,D
What year is your car? You have an E shift or M shift valvebody?
@@GaryFerraro 2008 x5 eshift
@@SEBAS31077 Does the car ever jump back to park on you while in drive or reverse? Is the trans full of fluid?
mr gary bmw 6hp21 how to know color for valve
you could drop the pan to see them