Ronnie G

So I’ve had my 911 for a while now and I’m having a blast. It’s a 2006 997.1 C2.

I recently posted about upgrades and complained of rough shifting between first and second. You guys gave lots of good advice in that thread and I appreciate it! The recommended solution for the gear shift was new transmission fluid, so I changed it out. Unfortunately, the problem persists.

To describe in better detail, I have a hard time engaging second gear from first and vice versa—it feels like there’s something blocking the shifter from locking into gear. The problem is most pronounced when the engine is cold and also at higher RPMs even when the engine is warm.

Before throwing money at a Numeric (it’s in the plans, just not right this minute), what are some other, less expensive options to get this one working as designed? Thanks in advance!

997.2GTS

New fluid is Mobilube PTX, right? Miles?

rtl5009

I would only put oe fluid in.

Pors968

I had grinding noise (not good one) on shifting into 2nd gear and it totally went away when I replaced engine mounts. I went with OEM mounts. Now all gears are shifting smooth. Gear grinding was really bothering me, and my Indy was telling that could be due to worn syncros and very expensive to fix. He was wrong. It's easy DIY job to change engine mounts and I'm very happy with it. You should try it.

RZau

So today here in NY it’s warm hence warmup of engine is quick. I paused in neutral for a split second then shifted and was a smooth shift. After a while I tried without pausing and even thought I feel it going into gear no grinding or extreme notchiness. I used the two finger method and let the car shift when it wanted to. High speeds nothing. Maybe this can work for some people with this 997 burden.
Rob

lucian95

Hi,

Just a naive question, as I'm not a mechanic. What is the connection between engine mounts and a shifter grinding from 1st to 2nd. Mine does the same when cold, so if I shift gently and at lower rpms, I can avoid it. Once everything is up to running temperature, it is gone.

RZau

Hi. I also am not a mechanic. I believe the worn out transmission mounts will move and that makes shifting not spot on. If someone can correct me or answer this question who knows little more it would be appreciated
Rob

bheit1

I just noticed this from a recent email by FCP Euro. Their blog has the most specs and advice I have
seen for the do-it-yourself mechanic. In another section on 997 manual trans. problems they mention that
Mobilube PTX is really required for the Carrera transmission synchros because it does not contain additives that
corrode the brass and bronze synchro parts. As mentioned above, most dealers just carry Moblil 1 Delvac
and use it in all Porsche manuals. To me, it's just outrageous that even the dealers are using the wrong oil -
no doubt it's cheaper. It should be mentioned that Delvac is fine for Turbos and GT cars with all steel synchros.
I thought I could count on Porsche's own dealers to provide products that met it's own specs. No wonder we
are having problems. You certainly don't always get what you pay for.

E39Nutz

Brass and bronze is more resistant to corrosion when compare to steel. The argument just does not make sense whoever made it up.

groovzilla

Warn engine mounts can result in poor shifting---->New egine mounts can perhaps help if yours are warn.

bheit1

If you log onto the FCP Euro blog and find the section on 997 manual transmission problems you will
understand what they are talking about. Some manual transmission additives are definitely more corrosive to brass and bronze -
that's why we have PTX. We aren't talking about water here.

Floyd540

Getting out of control here. I have pointed out before that finding/developing a lube for a manual shift transaxle is a challenge since the requirements are diametrically opposed. The hypoid ring and pinion involved sliding motion and not pure rolling gear contact motion, hence the need for extreme pressure slippery lubricant. The classic additive for this purpose is Sulphur
Moving on to the transmission section,, we have synchros that are nothing more than friction brakes that equalize the speeds so gear shifting can occur. This brake has to run in a lubricant for the gears, but the syncho does not want slippery but the gears do. A balance has to be found. On old timey trans, dating back to the 1920's, synchros were made of brass or bronze so they would wear as a brake surface and not shed steel shaving into the oil. They were softer and sacrificial and later designed to be replaceable,"synchro rings". In a transaxle, the Sulphur compound attacks the brass or bronze (copper). This has been known for decades with vintage cars that do not have hypoid rear ends. However is regular cars, the trans is a separate item and the diff is another element. That is why we ran Redline M/T in the transmission but ran Redline gear oil in the differential. When you throw in limited slip diffs, things get complicated. Newer trans with so much higher torque loads use steel and carbon in synchros and less brass.
Just use the Mobil PTX like they tell you.

E39Nutz

The only things i know will corrode brass and bronze are sulphuric acid and nitric acid. If anything that will corrode brass/bronze, it will eat through steel even faster. As a chemist, I don’t buy the theory that developed in the forum.

Floyd540

It is not theory. As a refresher, go out and look through the boxes of trans parts you have accumulated over the last 40 years working on cars, especially gear boxes and rear ends. Also a little reading of real API documents , not internet forums) and you will see the reason behind the spec for MT-1 and others. Also a quick check on shear calculations and temperature will show problems with yellow metals Other additives eliminate the oxidative reaction on ferreous metals. Tribology is a specialty.
However ,as I mentioned, for those interested in using the proper lubricants in you car , follow the directions. If you cannot draw molecule, for sure follow the instructions and the manufacturers advice.
Absolutely no need to dig into the acids of Sulphur or phosphorous or the levels in GL series of lubes. This has been done years ago.

bheit1

Amen!

When someone can't even be bothered to look at a blog and witness the problem at hand,
you have to wonder how they got through college. Or is this someone playing with ChatGPT?