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THIS DISCUSSION / SOURCE-DERIVED OVERVIEW
Discussion summary
YOUR RESEARCHTransmission fluid recommendations?
Leading reported evidence
Replace every 90k miles and the qty needed was 2.85qt
Performed · outcome unconfirmed
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0
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0
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1
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Performed · outcome unconfirmed
Before I did mine, my research resulted in Mobil Delvac 75/90 to be changed every 90k miles and the qty needed was 2.85qt.
Leading evidence: 'Replace every 90k miles and the qty needed was 2.85qt' (no explicit attributable resolution; this is a reported action or suggestion). Across 1 matching discussions, The most frequently discussed action is 'Replace every 90k miles and the qty needed was 2.85qt' (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.
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Performed · outcome unconfirmed · Original poster
I can�t find any evidence of mine ever being changed so with 75k, think it�s definitely time.
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Performed · outcome unconfirmed
I have a 99 C2 with factory LSD, and I replaced my trans/diff fluid with Porsche fluid.
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Suggestion · Original poster
Yes, Porsche recommends a 90k change interval for the fluid.
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11 eligible posts · 0 unverified posts · 1 discussions match the subject in their title or opening post.
Rennlist: 1 discussions
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Generation: 20261027T000231Z · outcome-qualification-6. Deterministic extraction; no AI model inference. How we use sources
Anyone have a particular transmission fluid they recommend? I can�t find any evidence of mine ever being changed so with 75k, think it�s definitely time.
Every other performance car I owned, there was a general consensus on a go to fluid. Not seeing a whole lot of input via searching so I figured I would ask.
Appreciate any input.
The word "fluid" typically refers to automatic transmission fluid; gear oil is for differentials and manuals.
I think OP should clarify which it is that is in question here.
Before I did mine, my research resulted in Mobil Delvac 75/90 to be changed every 90k miles and the qty needed was 2.85qt. I sourced it from my local dealer. This was from trusted sources but I�m sure there are plenty of other opinions out there.
I have a 99 C2 with factory LSD, and I replaced my trans/diff fluid with Porsche fluid. Same reason as you: I could not find that it was previously done before.
I believe the Porsche fluid is very similar to a Mobil 1 oil, but I ponied up for Porsche brand, because...Porsche.
Thanks for the responses everyone. This is not an attempt at saving money. Just looking for the best performing fluid for our trans.
Yes, Porsche recommends a 90k change interval for the fluid. However, after 16 years I think it�s life span has expired. I�m going to change it.
I do find it strange that Porsche would spec the same fluid/gear oil for the manual transmission with or without the LSD.
It could be that they designed the LSD to work with the standard fluid so as to not have to make things complicated and be able to share parts across other product lines.
