S8LEE

I'd like to prevent my trans from grenading prematurely and apply the fix before the A drum blows out and the valve body cracks. Is there a part number list for what I need for AYS/FBG 2002 S8?

ocles_inc

It depends. Essentially the way I do it is to drain the fluid (one hex bolt with a female head -- wow, that sounds transgender), then remove the transmission oil pan (26 Torx T-27 bolts that ideally should be removed in a crosswise fashion as if they were aluminum cylinder head bolts), then remove the filter (2 Torx T-27 bolts). Then I remove only the lower front valve body housing, shown as highlighted in green below.





I send that off to Nat Wentworth at Eriksson Industries
146 Elm St B, Old Saybrook, CT 06475

... and ask him to renew the pressure regulator. That's all he needs. He inspects the part I send, cleans it, bores out the tunnel to slightly oversize to get it true and round again, and installs an oversized piston made by the good people at Sonnax. Nat has the Sonnax parts in stock already. So, if you ask for it like that, you should not need to mention any part numbers.

You might want to give Nat a call and tell him what you intend to send, and confirm the pricing. Last I looked his phone number was (860) 388-4418 and his email address is eriksson.indust at snet.net ... if you tell him Tanya of OCLES referred you, and you want the same sort of magic he does for me, that should make it extra clear. You might during the initial conversation also want to mention that it's for a ZF 5HP-24A.

As I recall from reading the ZF parts manuals there are just two variations of this ZF 5HP-24A lower front valve body housing when assembled, "early A8" vs. "everything else" and yours is in the latter category, so no worries, but if there is anything screwy with the housing you sent in, Nat would no doubt get back to you.

So far Nat has renewed five or six of these for me, and the cars into which I've installed them have subsequently been driven hard, some very hard, to test them. That includes my own personal A6 Quattro V8 4.2, and so far, after 10,000 miles or so, no failures. Runs to Vegas, to LA, back and forth over the Sierras near Reno again and again, rock solid.

I suggest you resist the temptation to disassemble the housing before you send it. I've never done it but I've read that when you do, springs and parts shoot all over the room, or into your eye, at some point. As I recall Nat also disassembles and inspects the other internal parts as part of the service but in case you care, you might want to ask him.

So after a couple of weeks, you get the renewed part back to install, and your Audi is back on the road with a bullet-proofed transmission as far as the clutch "A" drum which is, based on which I've seen and heard, the most typical cause of failure. It's not the only cause though. The "F" clutch and torque converter are likely next points of failure, though typically quite a bit less imminent than the "A" clutch.

I've asked some smart people: wait, how do I know that the clutch "A" drum hasn't already been damaged and it's too late already? The reply I got was that when this type of failure occurs, it's typically near-instantly so if I haven't seen symptoms yet, I can stop worrying.

Here are some notes on how to remove the lower valve body housing, after the pan and filter have been removed. Keep in mind that even after you've drained the fluid there will still be some in the pan, and when you remove the filter, more yet will come out, and when you remove the valve body lower front housing, more yet will come out.

After you removed the pan, inspect the magnets (there should be a total of 4 in the pan) because if they have a lot of sludge on them, or they look like hedgehogs, your transmission might have bigger problems. Also, metal debris in the pan is always bad news.

As soon as you have removed the valve body housing, put the pan back on and tighten it snugly enough to keep dirt and dust out. Ideally that also means putting the hex head drain plug back in and torquing it to spec.

It'll take a lot of self-control to not wipe off all the little drips hanging from various places in the inside of the transmission, before you put the pan back on. Fight the temptation because you might introduce dirt from whatever you use to wipe the drip off. Rather have a dirty garage floor than a dirty inside of your ZF transmission, is my point.

Before starting removal, focus on the front-most lower-facing casting, take a good look at where the wiring goes and how the shift lever mechanically connects to the housing. I recommend taking many pictures, since my tech and I have made pretty much every mistake in the book on this subject, including pinching the wire-loom and denting the pan when we tightened the bolts, oops.

Once I understand what goes where, I remove the Torx T-27 bolts. One of the bolts holds the wiring guide plate in position. With the bolt gone, the plate hangs in position. I maneuver the valve body housing vertically down from the rest of the valve body while being aware that a guide pin on the driver side prevents it from moving laterally. Some of the Torx T-27 bolts have large heads, some have small heads. One type attaches the lower housing to the main housing, and one type goes through the main housing and threads into the transmission body. My notes tell me there are 11 small-head black bolts, 13 large-head black bolts, and one chrome bolt.

For the record, my notes show that the ZF part numbers for the lower front housing are 1058327022 or 1058427022 depending on whether you mean just the casting or the casting after it's been machined, and then this is all without the cool pistons, springs etc. installed, so mentioning the part numbers to a vendor runs the danger that someone savvy interprets this more precisely than you intended. That's why I rather describe to Nat in English (with a German accent, but still, sort of Englisch) what I want and since he knows the routine, we're clear.

Okay, so that's the recommended best practice for when you are willing to use your own core, and it's in good condition (which is reasonably to assume) and you don't mind waiting for a couple of weeks to get it back. If you do mind, then you can buy a core unit from me. Here's how the options play out:
https://usedtransmissionsforsale5hp2...22-1058427022/

If you're in reading overload, and you just want to order the core from me, you can do it here: Original used part 1058327022,1058427022 for 1999-2002 D2

If you order it, I don't ship it to you. I ship it to Nat, and he does his thing, and then ships it to you. You pay me for the core and some shipping, and you pay Nat for everything else.

Keep in mind that for assembly, you'll also need a new pan gasket and filter, and ideally the little O-ring around the filter neck too. I strongly recommend you buy the original ZF parts from Nat too, as part of the deal. If some of your pan bolts are stripped, Nat probably has some too.

The right fluid is honey-colored stuff. I buy that from Blauparts - just the fluid, not the entire service kit including gasket and filter since theirs are not the original ZF parts. Typically 7 quarts should suffice.

This time-frame might be a good time to also buy a J-shaped tool to stick into the fill plug. Also, a good hand pump is a prudent buy. As I recall we got ours from Blauparts too. Nice people.

The tool for the fill plug is a large hex head that fits onto a ratchet or extension. You can get that tool from Autozone stores, in my experience. It's normally sold in a set of three, with two other sizes you don't need.

To fill the transmission fluid to the right level is tricky, and we use the Ross-Tech VCDS software with their special cable, for that. The fluid has to be been 30 and 50 degrees Celsius when the transmission fluid starts running back down the fill plug hole; by design, that's how you know it's at the right level.

If you have any other questions, please ask.

~Tanya

jfrahm

I use the TransGo valve:
TransGo 5HP-24-PR

About $50 from Ebay or wherever. I have done 2 of them on my 2001 A8 and 2003 S8. In the case of my S8 the valve body was worn to the point where the TransGo valve stuck a couple times also and so I had to take it out and dress the sharp edges of the valve piston. I also went after the cupped part of the valve body to round off the edge that grabbed the piston. If my time machine was working I'd have just either done the Sonnax valve (see above) or gotten a new valve body $280 (I think this is correct):
Valve Body Housing 5HP24 - 5HP30
...and put the Transgo in that, although I think making the edges of the TransGo valve piston less sharp is a good thing in any case. Not rounded so much as going from "sorta sharp knife" to "spatula". If this is a bad idea please inform.

My other tips, well I have a lot of them on the other D2 site but in short you want to make sure the filter you get is correct in terms of inlet and neck length, and also I had two gasket failures with a silicone pan gasket I initially thought would be great but turns out they were terrible and the stock style was much much better... I learned after replacing two gummi bear gaskets.

For the filter you want the shorter neck and NOT the oval inlet.

Don't forget the filter O ring.

The tips on getting the bolts out w/o clearance are good, I also put in 2 hex heads with a couple washers in the tight location so the next miserable muppet (turned out to be me) has a much easier time getting the pan off. This is only an issue for the PFL and the S8, the FL A8 pan is clear to drop.

Notice that punt in the pan that holds fluid you cannot drain? Yeah that makes it pretty easy to slop ATF out into your hair and all over the shop floor.

My A8 valve body I think has less wear maybe due to my use of Lubeguard lo these many years.

It's a magic fix if you have not broken your trans yet. Cheers,
-Joel.

hillpc

OCLES and jfrahm, wow! Great info.

I got the pan gasket and filter from Autozone, and couldn't bolt up the pan because the filter's plastic suction pipe stuck down too far. I've seen that this is a common issue. I sawed if off enough to be submerged in the fluid but not touching the pan and thus restricting flow. I hope it works; I'll finish the brakes and the suspension bolts tightening (once the car's on the ground and the suspension is not hanging at full droop, in order to prevent the rubber bushings tearing when I hit a bad bump) hopefully this weekend to test drive the car and see if my A drum replacement worked.

Is there a spec for how far off the pan the pickup is supposed to be?

ocles_inc

I'm glad if I'm adding value with the information I post. Thank you!

I love my local Autozone but seriously, even if I had spent the money on a gasket and filter from them, I would not use them. I'd go get the original ZF stuff. I do buy and use a lot of non-OEM stuff too so I'd better explain myself. Some of the book knowledge, so to speak, that I learned about these transmissions, I learned from some YouTube videos by Gary Ferraro. I emailed him too. He's super-nice.

Anyway, as I understand him, he's not a purist on vague principle. When he chooses OEM stuff it's because he's seen the consequences when he doesn't, and he's rebuilt enough of these transmissions to have a lot of useful data on which to draw conclusions. So I'd urge you to go look at his video on the subject and if after that you still choose the non-OEM filter, then you're making a more informed decision than before you saw the video.

The fact that the Autozone filter pickup tube is too long is a red flag to me already. I don't know how big the clearance is supposed to be but here's what I understand:

The early A8 cars (through part-way or the end of the 1999 model run, as I recall) had a deeper oil pan and a filter optimized for that, with a 1" funnel. Then in 1999 or thereabouts the A6 4.2 V8 came along, which is basically a parallel of the Pontiac GTO: making a large V8 fit a smaller car.

Things went through a nip-and-tuck process including the oil pan being made more shallow and the filter being optimized for that, with a 3/4" funnel. From then on, I gather, Audi standardized and even the A8 from them on used the more-shallow oil pan and the 3/4" filter.

So one way to have issues is if someone made the filter too long and you have a shallow-style pan. As I recall you have the earlier style A8, yes? If yes, it can take the deeper pan, or the more-shallow pan. Originally it came with the deeper pan but maybe someone replaced it with the much-more-commonly-found shallow pan.

Nat Wentworth, of Eriksson Industries, the US ZF distributor, recommended to me I cut some triangular slots in the bottom surface of the filters before I install them, so if I ever hit something that pushes the bottom of the pan against the mouth of the funnel then the pump won't suffer oil starvation even so. I've been cutting slots ever since, for every filter my tech and I install.

I'm cheering you on as to your A8 being ready, yay! It's been a long journey. Thank you for all the help and guidance you've given my based on what you learned during your own project.

Please let me know how it turns out, even if it's bad news. The first transmission my tech and I installed after doing an "A" drum fix ... it behaved very badly but it turned out to be a quick and easy fix, though at the time it was very disheartening.

~Tanya

jfrahm

Did you do anything for the root cause that broke the drum?

I have also heard about the slot cutting for the oil pickup, I'd be more concerned about sucking air under some circumstances (like on a steep hill) and if I bash my trans pan I'll call a flatbed. As for how far off the pan it should be, you could probably calculate the area of the pickup and map that onto a cylinder, i.e. if the pickup is 35mm in diameter or about 1000mm^2 about 9mm of clearance off the pan would provide a similar area for flow (9mm x (35*3.14)). That's probably a bit much I think 7mm is more typical but that's just what pops into my head.

You can collapse the suspension (before putting the car on the ground or on ramps) and do up the suspension bolts with a jack under the knuckle but be mindful of not bending the brake backing plate. It's wise to remember do this, people that do not probably tear up the bushings in short order.

S8LEE

Lots of information here.
I already did the trans service (filter and fluid change) at 94k miles- the manual calls for it at 90k but I only got the car at 93k and it had no service history so I did it ASAP. I used the Blauparts kit- honey colored fluid and the filter and gasket they sell. When I took the pan off there was very little metal shavings attached to the magnets which I was very happy to see- the fluid was very dark but not completely burnt- I've seen worse. No leaks with the paper pan gasket and trans seems fine which is why I want to get ahead of the potential issue.

The only thing I dont like about the way the car behaves is that every once in a while I'll get a harder than normal downshift into 1st or neutral (not sure which one) when coming to a stop....This is what has me partly concerned.

So If I buy the new valve body and the transGo valve I will have to transfer all the other pistons/valves/ ***** (if there are any) to the new valve body, I assume -and prey I get it right. I've rebuilt a GM 700R4 trans from beginning to end about 10 years ago and only remember that if its not right it wont work.

Either way thanks for the replies - now I have options and can make an informed decision.

jfrahm

That was one of my pre-Transgo symptoms. If your valve body is not too worn it might be OK to just try the valve. My A8 got the valve at 165K and I am at 175K now and it's been rock solid. I also had a spooky 3-4 shift when the weather was cold and the car was cold. I did not have to go back in and monkey with the A8 valve or valve body like I did in my 108K mile S8.

In the S8 I found that the valve could stick in a few clock positions, and that there was some cupping/wear of the deepest 17mm bore. Deburring that a bit and rounding off the sharp edges of the TransGo valve seems to have eliminated this sticking and it's been perfect since. The minor shifting issues I'd had in the S8 went away with the TransGo valve but then I got a couple instances where it freewheeled and banged into gear, so the TransGo valve had been able to stick until I went in after it and sorted it out.

Here is a thread in which I think the VB is shown apart:
ZF 5HP24 teardown - Page 2

Probably this particular image? Looks right to me:
http://i260.photobucket.com/albums/i...ValveBlock.jpg

Maybe a bit fiddly to swap over everything but not brain surgery. Those weird looking eyeball things are bolts and screws.

ocles_inc

@S8LEE thank you for your kind words. :-)

Kudos on doing the transmission service so diligently. Most folks don't. Then again, some do and then they use red fluid ... not good.

As to "So If I buy the new valve body and the transGo valve"

If you're referencing my post, I should probably clarify that the "problem child" in the ZF 5HP-24A valve body is the hydraulic pressure regulator and two possible fixes are the TransGo kit and the Sonnax kit. The US ZF distributor, Eriksson Industries, renews the hydraulic pressure regulator using the Sonnax kit, not the TransGo kit. If he endorsed the TransGo kit instead, I'd be buying that instead.

I actually bought a TransGo kit before I was aware of the Sonnax kit but I haven't used the TransGo kit and I might never. Even so, I like the TransGo people. Their instructions are written in a cheerful and fun way that made me glad, for once, to have read the instructions. They are also pretty candid about the need to be very careful when disassembling the relevant valve body housing, because spring loaded internal parts will otherwise go flying all over the room.

That was enough to make me decide the stakes were high enough to go pay a pro to deal with that, which is where Eriksson Industries comes in, even though they don't use the TransGo kit, they use the Sonnax kit.

I don't have any formal basis for saying the latter is better. Even so, Sonnax generally comes across by my standards as a more formal transmission-centric, transmission-savvy engineering concern so it's tempting for me to choose them just for that reason. For all I know, the cheerfully informal TransGo people are no less brilliant.

I suppose you can go buy a new valve body but you'd probably save a lot of money and quite possibly be no worse off, if you narrow your focus to just the lower front housing, and from there to just the hydraulic pressure regulator in the lower front housing. That's what I've been doing. So far, so good.

The good news is that to do this valve body work you don't have to remove the transmission nor rebuild it. You drop the pan and filter and then the part you need is right there, ready to be removed. The more I learn about Audis, the harder it becomes to hide a secret smile, when I hear someone saying they're hard to work on.

~Tanya

hillpc

Yes, the pressure regulator was updated by purchasing the appropriately modified section of the valve body from Eriksson.