Tiptronic Transmission: rebuilding vs. buying remanufactured?

So I have a small issue with my transmission, and will likely be proactive this off-season to get it addressed. No one's been exactly sure the cause, but going into or out of 4th gear (only when fully warmed up) there's a slight lag in the clutch engagement. In auto mode where it shifts at much lower rpms it's not even noticeable, but when spirited driving in manual mode at higher rpms, the lag in clutch engagement (maybe just inside one second) is much more pronounced. Short term, being aware of it allows me to more closely match rpms to the next gear (meaning no downshift to bleed off speed going into a corner) as I would in a manual with a bad synchro. The shop (reputable Porsche specialist in WI) talked to their trans shop, who recommended it would be more cost effective replacing it with a manufactured transmission rather than repairing mine. Has anyone had experience with going this route rather than having your current transmission rebuilt?

From all I've been reading is that the 5HP19 which is the transmission in the 99-01 Tiptronic 911s should be easy to rebuild and parts are plentiful and cheap as some variation of this transmission was used in a ton of European cars in the late 90s'-early 2000s. If it were my car I would rebuild and upgrade the known weak spots while in there, so I would see if you can get a few more opinions from other shops

What would be an example of a weak spot? Assuming the trans will be shipped to whoever does the work, any suggestions for shops I should talk to?

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Hows the trans oil level..? Have you dropped the trans pan to see whats in there..? Has the fluid been changed recently, how about the filter..?

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This was our first thought. Had a full fluid flush and new filters three weeks ago. Issue persists.

The rebuild is straight forward it's the valve body that's the hardest. I went through this on a Boxster S I had. The transmission shop rebuilt the transmission easily - they then put the old ("cleaned") valve body back in and the car would stall in D or R. Had to replace the valve body with a good used one. Watch out for this if anyone rebuilding their transmission and ask the transmission shop can disassemble the valve body and refurbish it as well. Might be different in the US but here in AU we don't have many if any shops that can work on the valve body aside from "cleaning" it which was in my case a waste of time and money.

Hi Dan, in NSW, Australia - Autowerks Wyong have good ZF rebuilds that are done combined with a Sydney site. Mine was a high torque LN 3.4 to 3.8 stressing the transmission. To manual lovers I'm a veteran, a manual is too much for me in Sydney traffic. Air cooled manuals are very pricey in Australia, not used daily as far as I can tell. In Australia a 996 is not cheap to buy, or pay for skilled servicing.

Thanks, I didn't have any trouble finding places that would rebuild the box, that's the relatively straight forward part. The valve body is an entirely different matter. ​​​​​

Trans-GO makes some updated valves for the 5HP19 ZF tranny.. The valve body wears in the valve bores of the pressure regulator and causes too much pressure, this excessive pressure can destroy a little o-ring in the torque convertor for the lock-up clutch, also the excessive pressure will cause the front pump bushing/seal to fail... So torque convertor/lock-up clutch, and front pump bushing/seal are the main failures of the ZF tip caused by worn valve body.. Like has been mentioned, the 5HP19 was used in many other cars, BMW's ect, so parts are easily available except the tail housing gasket, that is unique to Porsche I think.. Like mentioned the trans is easy and common, the valve body is tricky and finicky..

5HP19 ZF tranny I assume this is the tip for a '99?

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So, assuming the valve body is still part of the internals of the trans, could I safely assume this would be addressed in a re-manufactured trans, or are the Trans-Go valves something I would specifically ask to be addressed/upgraded in a rebuild of my current trans?

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Yes That would require a lot of assumption on my part, and I don't like to make assumptions.. But I would advise you to ask these questions, and a rebuilder would have to convince me that the bores in the valve body were good and/ or was updated with the Trans-Go updated parts

What he said ^^^ - the first and foremost question to whichever source is selected for an outright rebuilt trans unit is 'is the valve body included' and the next is to ask what kind of warranty is on the valve body as well as the whole box. I'm subscribed because I have a '99 911 tiptronic, but I'm hoping that I never have to use this information!!!

I am a little confused by some of the posts. These transmissions cannot be rebuilt except by Porsche (Aisin). They can be serviced, but servicing is limited to replacing the valve body assembly, its control unit, and seals. Fortunately, the OP's problem may indeed be with the valve body assembly.

^^^ Pretty sure you are mistaken, a 996 will have either a ZF or a Mercedes auto box. Both are used in lots of other cars, rebuild kits are mostly readily available (some gaskets might not be easy to get), and ATSG has rebuild manuals for both.

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Are you thinking of the PDK transmissions? This is actually why I changed course and got the 996 [EB] over a 997.2 PDK.

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The ZF 5HP19 is so common that Billy Bob at AAMCO could probably rebuild it on a good day.

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My mistake, reading too fast, was thinking PDK. Apologies.

Quick update on my phantom shift flare. After being told to replace the transmission and digging deeper (many thanks to this thread) I found a shop to examine and rebuild the valve body (Ream Man Valve Bodies). Turns out somehow the lubrication value was installed backwards (?!) and several vacuum seals were shot, likely due to improper lubrication from this valve issue, and pulling well below the vacuum pressure they should be at. Fresh upgraded internals and tested on a dyno, we're back to 100%. It'll be reinstalled in January, and hopefully this solves the issue. If it does, I'll come in at <10% the cost of a transmission.

And a final update: Got the car back two days ago, brief window between snowstorms where it was sunny and dry roads for the 130 mile drive back from the specialty shop (hat tip to Rick Fischer at Fischer Motors) With about 40 miles left on the return trip I went into manual mode and started running through the gears. High rpms, accelerating upshifts, downshifts for breaking, back and forth and up and down the gears for 30 miles. Not a missed nor delayed nor flared shift to be had. Quick, firm, and smooth shifts. It was straight to storage, so I won't be able to double check again for a couple of months, but it sure seems to have been solved. I also got a new OEM headliner installed while it was in the shop. What a difference! Apparently a prior owner must have tried to DYI an aftermarket headliner, and never pinned it properly (and they tried to glue it, failed), and it was just waiting to snag hard when going up and ruin the mechanism when it would have been the most inconvenient timing, of course.

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Excellent, !! How much did the valve body expert reman cost ?

$550. Plus shipping.

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like hitting� the lottery!