what a difference after transmission fluid change!

i started my first DIY on my new to me C4s over the weekend. The list is long... So far the oil, filter, serp belt and tranny/rear diff fluids are changed. My car has the BM ssk on it and cold shifting was horrible. It sometimes grinded in to second. I cringed before 1-2 shifts in cold. Over the weekend I changed the tranny fluid. Probably factory fill, it came out brown and really dirty. I talked to Eric at Gbox. They rebuild a lot of transmissions and have created the shift detent. He said not to worry about type of fluid as long as i find the correct weight synthetic. So I ordered 5 liters of lubo molly from authausaz.com The front diff fill bolt is troublesome so I have NOT changed that one yet. But I was able to change the tranny/rear diff. This morning I took the car out in 22 degree weather in Denver. holly smokes, the gear box never felt this smooth before. Instead of cringing before shifts, I was actually looking forward to shifting. I am still going to take the BM SSK out and replace it with the 997 regular shifter that is enroute. but it feels great!!! Very satisfied with the results. IMHO you don't need to stress about finding shell fluid from the dealer. I don't want to open a can of worms on the fluid choice. Everyone has differing opinions. I am satisfied with lubmolly after seeing how smooth my gear box is currently. Let me know if anyone wants a BM kit. It will for sale soon.

Good work and suprising result. Hope you manage to remove the bolt on the front diff. I was never into DIY on my other cars but the quoted price of repairs to a Porsche got me more than interested. Now I am looking for preventative maintenance work on mine and so far have not hit on anything I cannot do myself. Cleaning the crap from between the rads and condensors is a very easy and satifying job to do yourself. Next on my agenda are plugs but I am not rushing into that job as yet as the engine is running bang on right now. Brakes are very interesting and there are films on youtube which help me with my work. Changing coolant system and brake fluid was satisfying work. Anyway keep up the good work.

I changed the fluid in my 6spd at 58k ... also lubromolly ... old fluid was brown ... the only issue I saw after change was 2nd gear pop out issue became for frequent for about 1 k miles .. but since then the issue has gone away ( before change it happened a couple of times but not frequent enough for me to want to fix) ... now I guess ill keep driving ... if it comes back will consider gbox mod ...

If you haven't replaced the motor mounts yet, that also makes the 1 & 1-2 shifts much smoother & easier. Especially if you ever got that random "clunk" during the 1-2 that sounded like you did something wrong, but was sure you didn't. Gone after changing out my mounts.

Please let us know how you like the 997 regular shifter vs. the BM SSK. I'm curious to see if you have a little more 'feel' of the synchros and what is going on with the transmission via the regular 997 shifter.

the 997 shifter just arrived. It will be sometime (week) before I will have the swap done. Honestly the fluid change made the BM feel so much better that I am questioning putting in the few hours for the swap.

Gbox did an AWESOME rebuild on my transmission and diff. Feels like a brand new car. Shifts great even in below 0 temps. My trans wear was too severe for the Gbox fix to work or a trans fluid change. Happy with it now though

Thanks for the post, Didn't think it would be that dramatic a change, gotta move this to the top of my list.

I am still blown away by the positive results on fluid change. Never had a gear box be so happy with new fluid on my other cars. 997 kit will go in this weekend. Let me know if anybody wants my already installed into the housing b&m ssk.

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I added the motor mounts on the list as well. Hope to get them ordered soon.

I just replaced my 8yr 11k miles gearbox fluid as preventative maintenance and used Amsoil 75W-90 Severe Gear oil... DO NOT USE THIS GEAR OIL. The shifting instantly became very notchy and on cold mornings (just above freezing) it will barely go into gear now. I will dump this oil and try another fluid, but I recommend all you DIYrs out there avoid this specific one... learn from my $50 mistake. I may just try another OTC synthetic 75W-90 gear oil for fun this weekend before I give up and go to the Porsche approved gear box oil... Who knows... maybe if I was in 100 degree weather on a track this stuff would be the bees knees... but not in temperate climates with moderate usage like my mixed driving! FYI

Anyone know if our trannies prefer synchro friction modifier additives or not? That might partially determine the fluids you should definitely stay away from.

Well, it is already easy to determine which fluids to stay away from if one trusts Porsche. Copied directly from the factory manual in the transmission fluid change section (and the engine oil change section, the ATF change section, the rear drive fluid change section). "Use only oils approved by Porsche. See Parts Catalogue!" If one doesn't trust Porsche in this regard then one can make his own fluid selection based on whatever criteria he wants to use to justify his selection.

I highly suggest using stock fluid! And there shouldn't be much of a difference at all once you swap it out.

The stock fluids argument can go on and on as historically proven. I as well as others on here are curious and open to other alternatives. BTW, I don't run Michelin N rated tires either.

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Of course, I hear you... but I'm saying this with experience and through trials. The stock one is a very premium oil, Any other fluid, I'd go aftermarket.

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Thanks for the words of wisdom and taking one for the team. I'll keep that in mind (and most likely go with stock on this one) when it's time for me to do a flush. But still like to know if the stock Porsche Fluid uses synchro friction modifiers or not in it's formula.

I have filled with stock and also Royal Purple tranny fluid in my 996. Royal Purple was drained after 5K miles because it was just not smooth in colder weather. Stock tranny fluid for sure.