12 captured repliesDiscussion pagination complete · Source accounts, not a confirmed diagnosis
THIS DISCUSSION / SOURCE-DERIVED OVERVIEW
Discussion summary
YOUR RESEARCH1999 C2 Transmission gear oil
Leading reported evidence
Replace fluid
Performed · outcome unconfirmed
No successful repair reported for this finding.
0
Reported fixes
0
Unsuccessful attempts
1
Discussions
Read evidence and context
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that performed work without a confirmed outcome
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Performed · outcome unconfirmed
I replaced my fluid with valvoline full synthetic 75w-90 GL5 back in April.
Leading evidence: 'Replace fluid' (no explicit attributable resolution; this is a reported action or suggestion). Across 1 matching discussions, the most frequently mentioned possible cause is 'first gear issue' (1 discussions; 0 report identifying it and 1 suggest it). The most frequently discussed action is 'Replace fluid' (1 discussions). For that action, 0 discussions report a resolution and 0 report an unsuccessful attempt. No action has an explicit, attributable resolution report under the current rules. These are forum reports and suggestions, not a confirmed diagnosis.
Source reports, not a diagnosis or a success probability. Counts refer to discussions and can overlap.
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that performed work without a confirmed outcome
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that suspect a cause
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Suspected cause
I suspect the first gear issue on my car is probably the trans mount or the shift linkage adjustment.
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that suspect a cause
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Suspected cause
I suspect the first gear issue on my car is probably the trans mount or the shift linkage adjustment.
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that contain suggestions
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Suggestion
I believe that folks that report a slightly better shift when replacing the trans oil are due to one of the following things:
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Unsuccessful attempt
That said, I have almost no traction issues with my car, even at threshold braking at the track, so I don�t care much of the LSD is up to par, but I still replaced the trans oil with Porsche fluid 2 years ago. No change to my cold shift issue I�m getting into first gear when rolling to a stop, but it doesn�t bother me so much.
Counts describe captured discussions, not unique people or a diagnosis. Author identities are not reliably stored. Exact duplicate evidence is counted once across matching discussions; one discussion counts at most once per action/state. Multiple repairs reported together remain a combination. Suggestions and failed attempts do not establish a fix. Matches cover whole discussions and can include related faults, model variants and incomplete threads.
12 eligible posts · 0 unverified posts · 1 discussions match the subject in their title or opening post.
Rennlist: 1 discussions
0 evidence records excluded for query context · 0 excluded by outcome qualification · 0 adjusted by outcome qualification.
0 acknowledgements have no verified action link; they do not establish a repair result.
Generation: 20261026T144035Z · outcome-qualification-6. Deterministic extraction; no AI model inference. How we use sources
I am getting ready to do a fluid swap in my 99 996 C2 6 spd manual. My owners manual says to use 75w90 gear oil. Does anyone here trust any of the other brands besides Porsche brand?
I have read a couple of threads here and on RennTech about what transmission oil is best. Stories go like this: I replaced my transmission fluid a few months ago and now I think something is wrong with my transmission. Then I took it to my indy/dealer/transmission specialist and the first thing they did was drain out all of what I put in there and replaced it with the Porsche transmission fluid. All my problems went away.
Moral of the story - replace the transmission fluid with Porsche transmission fluid correct for your car. Don't second guess this one, and don't look back.
I put Red Line in my '99 C2 shortly after I bought it three years ago. Seems like it shifts a little better than whatever it replaced. Then again, it could be my imagination.
I believe that folks that report a slightly better shift when replacing the trans oil are due to one of the following things:
1.) The replacement oil is slicker (such as Teflon or another additive that makes shifting smoother and easier)
2.) The old oil was bad/old/low
3.) Placebo affect
The issue I see with #1 is that it could cause premature wear of the synchros in the transmission. An easier shift could mean a faster shift, which could cause more wear at the expense of convenience.
There are probably quite a few oil brands and types that would be suitable as a replacement, but if you go that route, I would research it thoroughly.
If you car has an LSD, it should be printed on the options sticker on your hood. LSD for a 99 comes with 3 total options (220 - SPERRDIFFERENTIAL, 222 - TRACTION CONTROL (ASR), and 224 AUTO. BRAKE DIFFERENTIAL (ABD))
The Porsche trans fluid is compatible with the Porsche LSD, even if the LSD is not working 100% as it did when new, which is quite likely. Most 21-yr-old 996 LSDs would need to be rebuilt at this point to work properly. My car has an LSD and I have no idea how well it is working. That said, I have almost no traction issues with my car, even at threshold braking at the track, so I don�t care much of the LSD is up to par, but I still replaced the trans oil with Porsche fluid 2 years ago. No change to my cold shift issue I�m getting into first gear when rolling to a stop, but it doesn�t bother me so much.
I suspect the first gear issue on my car is probably the trans mount or the shift linkage adjustment.
