C2 Manual - Gearbox Improvement!

Team, Thought I'd make a quick post as I have just transformed how my manual gearbox feels! Whilst she was up in the air for underbody cleaning and protection I thought I would fit the Powerflex Gearbox mount bushing inserts (Yellow) and at the same time change the gearbox oil to Shell Spirax S5 ATE 75W 90 Not sure which change contributed what to the overall improvement, but even when cold all notchiness and struggles to get into 1/2 was gone, just a very direct feeling and positive location with no noticeable increase in NVH. The gearbox oil was last changed 20K ago by a famous indie but I don't know what was used, and I'd read mixed reviews on the Powerflex inserts but decided to give them a go. Highly recommended, feel loads better so I thought I would share! Cheers

Quotes source post: 2715218

I have bought exactly the same one, my understanding is that you tighten the mount on the yellow powerflex bush then undo it which has left an inprint, you then cut off the excess surrounding the imprint which means that the bushing doesn't touch the other parts of the car which, by all accounts, eliminates the NVH.

Quotes source post: 2715221

Yes there was a discussion on this I was reading from back in 2017 lead by Alex I think. There was a bad NVH issue with the first release of the Powerflex due to the gearbox bracket clamping the insert down onto the gearbox frame therefore not isolating the vibration to just the bushing. The fix was as you described to remove the excessive insert material. The Powerflex MD joined in the threat and his engineers created a new version of the bush with thinner 'ears' on it which reportedly solved the issue. I fitted the new version and was half expecting a trade-off between NVH and tightness, but I was very pleasantly surprised as it was 100% positive result with only desirable effects hence posting my experience. I took specific care to ensure the insert was seated all the way into the bushing using silicone grease, a rubber mallet and using one of the bolts in the lower bush hole either side to 'lever' the top gap open so I could get the insert all the way in. Then when tightening up I was careful to ensure no poly was compressed, the mount is firmly against the metal core of the original rubber bushing and the insert is not caught/trapped or pressing directly on anything, just held inside the original bushing. Very pleased with it made a really good difference to shifting feel, even my clutch engagement feels better and the car just subtly 'sharper'.

A change of oil especially if it’s not been done for a bit should always help with how it feels

This thread is useless without detailed pictures and or video excellent result. I've just had the transmission oil changed and noticed a little better gear change too although the oil was changed a little over 4 years ago and the gearbox was replaced by Porsche in 2005 in 45k so should feel good anyway. No SSK as far as I can tell but it's rifle sharp. Tell me more about these power flex items please.

Here: Thread 'Powerflex gearbox mounting bush insert kit - WOW!' 27 May 2017 I ordered myself some of the Powerflex gearbox mounting bush inserts the other day afterfinally deciding to have a go at them once seeing infrasilver had took the plunge. There's always felt like something is a bit slack or wear with the drivetrain on my 996. Nothing bad but I've had the impression it didn't drive as factory standard. It's as though there was some backlash in the gears noticeable when you quickly release your foot off the accelerator or dump your foot on it when coasting. I changed my engine mounts some time ago as you could rock the engine under the car when... Alex Replies: 46 Forum: Porsche 911 996 (1997-2005) and here: Thread 'Powerflex gearbox mount bush insert - 996 Review & Mod.' 6 Aug 2017 After I fit the Powerflex gearbox mount inserts I posted about the transformation it made to the car with regards to handling and NVH and stated that after I'd been on my lads holiday I'd review them and take appropriate action. I'm back off in less than 3 week on another 2.5k trip with my good lady and the dog so wanted to be happy with them before that so yesterday I decided to remove them and do the infrasilver hack . With regards to the performance of these up to now (after 2 months and around 3k miles) they did bed in more as time/distance went on and the NVH was reduced, but... Alex Replies: 72 Forum: Porsche 911 996 (1997-2005)

I've just had one of these arrive and the gearbox oil too, I'm looking forward to doing the change!

Quotes source post: 2715247

Really pleased with mine, got up at 5 am for a blast through the Cotswolds this morning before the traffic started! Well worth it, but feeling knackered now though!

Quotes source post: 2715239

Have a read through the threads Alex has linked to below, it was reading those that made me want to try the inserts. I was half expecting to be pulling them back out again after a week, but no, all good! I have stock engine mounts with <10K on them and no SSK and the gearbox oil wasn't old but was unknown so I went with the Shell Spirax as I think it is Porsche OE and can be bought in litre bottles not just £300 pails like the Mobil OE stuff.

Is this something I can do myself chaps?? Just read it and realised it's probably not But definitely worth looking into.

Quotes source post: 2715323

Its pretty straightforward as long as you can get the car up on stands/lift. Have a look at this video where the chap does both gearbox oil change and fits the insert, its only 6 nuts and two bolts. (Ignore the fact he drained his gearbox oil before checking he could get the fill plug undone!) .