r6cavy

2002 996 c2 cab...I’m having this surge/ lunge when my tiptronic shifts from 2nd to 3rd I’m both auto and manual mode. It’s become more noticeable as of late. Also get a thump when going from 3rd to 2nd but only on auto mode. I was told the tip module was replaced during engine rebuild before I purchased.ice also reset the tip values with no luck. Any suggestions? Could it be as simple as low tip fluid(fluid was replaced 10k ago) trans mounts? Solenoid? Wrong TCU?

r6cavy

bump

QUOTE=r6cavy;16874990]2002 996 c2 cab...I’m having this surge/ lunge when my tiptronic shifts from 2nd to 3rd I’m both auto and manual mode. It’s become more noticeable as of late. Also get a thump when going from 3rd to 2nd but only on auto mode. I was told the tip module was replaced during engine rebuild before I purchased.ice also reset the tip values with no luck. Any suggestions? Could it be as simple as low tip fluid(fluid was replaced 10k ago) trans mounts? Solenoid? Wrong TCU?[/QUOTE]

Dr_Strangelove

Bumping for you, sorry I have no experience with this. As an owner of other marque automatic cars if you think the fluid is old that is definitely where I would start.

Cheers and batsignal to @Porschetech3 - if anyone has seen this Ptech has.

sasilverbullet

Our tips are very persnickety and only the dealer can reset problems and troubleshoot it correctly.
Suggest you ensure that you have the correct amount of fluid, if that's ok, take it to the dealer for diagnosis.

Tipper

engine mounts are easy to check; take one out at a time
If its got the Merc gearbox with the mount separate (1 in the picture), the front one is also easy-ish to get at/out.

Porschetech3

LOL,,Thanks for "farming me out" !! j/k ...I'm glad to help if I can. It's one of my retirement pastimes. It doesn't pay well, but if y'all keep working and paying taxes between my SSI and selling a few UAOS's I'll make it ok..

[/QUOTE]

Well, with the new TCU sounds like a professional has tried to fix it, but was unable? Are you planning on fixing your self? OR just gathering information to be more informed when you let someone else repair it?

There was a TSB that sounds very similar to your complaint, and the fix is replacing the TCU with an updated one with better software.. It should have a part number ending in "07"... I'll post the TSB below.

Usually when someone replaces a TCU (if not for the TSB) it is a last ditch effort, or a "Hail Mary" when they have exhausted all other means of testing, theory's ect.

Having said that, always start by checking the fluid level, fluid condition, then check for fault codes, also a look in the sump will reveal the general health of the trans just like looking in the sump of the m96 engine. Look for metal debris and clutch material sludge otr any o-ring bits..

The 02 up uses the Mercedes 722.6 trans that is configured to fit the m96 engine and rear wheel trans-axle, but the "guts" are the same as all Merc 722.6 trans.

Common problems on the Merc 722.6 is the wiring harness connector will get oil into it and cause freaky problems, there is an updated connector and wiring connector to fix this. Also the "conductor plate" has some speed sensors built into it that fail and cause issues, common problem on the 722.6 whether used in the Porsche , a Mercedes, or a BMW.. you wont find any You-Tubes for the Porsche, but you can easily find them for BMW Merc 722.6..

Porsche doesn't allow the dealer techs to rebuild these Tiptronics, but before I was a Porsche Gold Meister, I was a Mitsubishi Master(10 years), and a Ford Master (20 years), and have rebuilt quite a few automatics..Porsche doesn't even offer any of the" hard parts (guts)" through the parts chain, just a torque convertor, a filter and gasket, a couple external seals.But I rebuilt my ZF Tiptronic (996.1) 10 years and 80k miles ago using a BMW transmission overhaul kit..

Here is the TSB, might be your problem. Pull your TCU and check the part number to see if it has the updated TCU..

ZuffenZeus

Had the exact problem on several of my Volvo 3.2L cars. The brake booster pumps were located directly above the TCU cable connector. When the oil seals on the brake booster pump began to deteriorate, oil would drip down onto the cable and create the same problem with rough shifting. Cleaned the TCU cable and replaced the seals on the pump and problem was solved. Volvo knew and admitted the problem and even sold a brake booster repair kit. Their charge was just under $400 to install a couple of cheap rubber seals. I did it myself watching a YouTube video.

Dr_Strangelove

I had an old boss that used to say "This is what you get for being useful."

r6cavy

Well, with the new TCU sounds like a professional has tried to fix it, but was unable? Are you planning on fixing your self? OR just gathering information to be more informed when you let someone else repair it?

There was a TSB that sounds very similar to your complaint, and the fix is replacing the TCU with an updated one with better software.. It should have a part number ending in "07"... I'll post the TSB below.

Usually when someone replaces a TCU (if not for the TSB) it is a last ditch effort, or a "Hail Mary" when they have exhausted all other means of testing, theory's ect.

Having said that, always start by checking the fluid level, fluid condition, then check for fault codes, also a look in the sump will reveal the general health of the trans just like looking in the sump of the m96 engine. Look for metal debris and clutch material sludge otr any o-ring bits..

The 02 up uses the Mercedes 722.6 trans that is configured to fit the m96 engine and rear wheel trans-axle, but the "guts" are the same as all Merc 722.6 trans.

Common problems on the Merc 722.6 is the wiring harness connector will get oil into it and cause freaky problems, there is an updated connector and wiring connector to fix this. Also the "conductor plate" has some speed sensors built into it that fail and cause issues, common problem on the 722.6 whether used in the Porsche , a Mercedes, or a BMW.. you wont find any You-Tubes for the Porsche, but you can easily find them for BMW Merc 722.6..

Porsche doesn't allow the dealer techs to rebuild these Tiptronics, but before I was a Porsche Gold Meister, I was a Mitsubishi Master(10 years), and a Ford Master (20 years), and have rebuilt quite a few automatics..Porsche doesn't even offer any of the" hard parts (guts)" through the parts chain, just a torque convertor, a filter and gasket, a couple external seals.But I rebuilt my ZF Tiptronic (996.1) 10 years and 80k miles ago using a BMW transmission overhaul kit..

Here is the TSB, might be your problem. Pull your TCU and check the part number to see if it has the updated TCU..


[/QUOTE]
thank you for all the info. I’ll check fluid level and mounts. If all looks good I’ll bring it to my local Porsche Indy.

r6cavy

Well, with the new TCU sounds like a professional has tried to fix it, but was unable? Are you planning on fixing your self? OR just gathering information to be more informed when you let someone else repair it?

There was a TSB that sounds very similar to your complaint, and the fix is replacing the TCU with an updated one with better software.. It should have a part number ending in "07"... I'll post the TSB below.

Usually when someone replaces a TCU (if not for the TSB) it is a last ditch effort, or a "Hail Mary" when they have exhausted all other means of testing, theory's ect.

Having said that, always start by checking the fluid level, fluid condition, then check for fault codes, also a look in the sump will reveal the general health of the trans just like looking in the sump of the m96 engine. Look for metal debris and clutch material sludge otr any o-ring bits..

The 02 up uses the Mercedes 722.6 trans that is configured to fit the m96 engine and rear wheel trans-axle, but the "guts" are the same as all Merc 722.6 trans.

Common problems on the Merc 722.6 is the wiring harness connector will get oil into it and cause freaky problems, there is an updated connector and wiring connector to fix this. Also the "conductor plate" has some speed sensors built into it that fail and cause issues, common problem on the 722.6 whether used in the Porsche , a Mercedes, or a BMW.. you wont find any You-Tubes for the Porsche, but you can easily find them for BMW Merc 722.6..

Porsche doesn't allow the dealer techs to rebuild these Tiptronics, but before I was a Porsche Gold Meister, I was a Mitsubishi Master(10 years), and a Ford Master (20 years), and have rebuilt quite a few automatics..Porsche doesn't even offer any of the" hard parts (guts)" through the parts chain, just a torque convertor, a filter and gasket, a couple external seals.But I rebuilt my ZF Tiptronic (996.1) 10 years and 80k miles ago using a BMW transmission overhaul kit..

Here is the TSB, might be your problem. Pull your TCU and check the part number to see if it has the updated TCU..


[/QUOTE]
I need to find the Tip control unit to make sure It was replaced with the correct updated part number. I read it’s in rear passenger wall. Any videos on how to access? Also is the replacement TCU plug and Play or dies Porsche need to program it?

r6cavy

Well, with the new TCU sounds like a professional has tried to fix it, but was unable? Are you planning on fixing your self? OR just gathering information to be more informed when you let someone else repair it?

There was a TSB that sounds very similar to your complaint, and the fix is replacing the TCU with an updated one with better software.. It should have a part number ending in "07"... I'll post the TSB below.

Usually when someone replaces a TCU (if not for the TSB) it is a last ditch effort, or a "Hail Mary" when they have exhausted all other means of testing, theory's ect.

Having said that, always start by checking the fluid level, fluid condition, then check for fault codes, also a look in the sump will reveal the general health of the trans just like looking in the sump of the m96 engine. Look for metal debris and clutch material sludge otr any o-ring bits..

The 02 up uses the Mercedes 722.6 trans that is configured to fit the m96 engine and rear wheel trans-axle, but the "guts" are the same as all Merc 722.6 trans.

Common problems on the Merc 722.6 is the wiring harness connector will get oil into it and cause freaky problems, there is an updated connector and wiring connector to fix this. Also the "conductor plate" has some speed sensors built into it that fail and cause issues, common problem on the 722.6 whether used in the Porsche , a Mercedes, or a BMW.. you wont find any You-Tubes for the Porsche, but you can easily find them for BMW Merc 722.6..

Porsche doesn't allow the dealer techs to rebuild these Tiptronics, but before I was a Porsche Gold Meister, I was a Mitsubishi Master(10 years), and a Ford Master (20 years), and have rebuilt quite a few automatics..Porsche doesn't even offer any of the" hard parts (guts)" through the parts chain, just a torque convertor, a filter and gasket, a couple external seals.But I rebuilt my ZF Tiptronic (996.1) 10 years and 80k miles ago using a BMW transmission overhaul kit..

Here is the TSB, might be your problem. Pull your TCU and check the part number to see if it has the updated TCU..


[/QUOTE]

So I brought to my local Porsche Indy who is supposedly very good. I’m not so sure. Suggested that I do a fluid and filter change and replace the differential fluid.They told me the previous shop put the wrong filter on, used the wrong fluid and there was a little debris in the pan. So service was done at $800 and did not fix the 2-3 late shift or the 3-2 bump.suggested I need a new transmission. They also told me I needed 3 bulbs and were going to charge me $175 to install. I told them... no fn way. I’ll do it myself. I got home.. all my lights work just fine. So now I’m thinking, if they can’t diagnose fn lights how can the diagnose a transmission. In manual mode I can shift at rpm to limit the lateness and harshness of the shift and the thump.its still there but if I take my foot off the gas it engages smoothly. I’m guessing it’s more of a solenoid or sensor issue as you suggested. Should I take it to a Mercedes specialist instead to diagnose. I no longer trust this this shop. It’s a shame too. They come very highly recommended.

Porschetech3

DID you or anybody verify the TCU is the part number in the TSB that ends in "07" ??

r6cavy

I was told it was verified based off what was read by the computer. But was not visually verified. It’s just weird how I can manipulate smoother shifting in manual mode. I still get a slight 2-3 surge but not as harsh, especially when I take my foot off gas. I can eliminate the 3-2 thump by downshifting at a higher rpm.. if I wait I get the thump. I just can’t believe I’d need a new transmission when every other gear is so damn smooth. No grinding. No slipping. Uggg annoying

Porschetech3

The only other common simple fixes on the Mercedes 722.6 transmission is the "conductor plate" and fluid in the connector/harness. Have these checked by a "transmission specialist" who is very familiar with the 722.6 trans..

If one of these is not your issue, you may very likely need a trans overhaul.

r6cavy

Thanks
Ill see who I can find in the Syracuse NY area. Any chance it could be the 2-3 solenoid? Or would that show up as a code?