Bruce In Philly

2009 C2S 86K miles, all year, all weather driver

OK, why? Why did changing my transmission gear oil with Mobilube PTX, as spec'd in my owner's manual, smooth my shifting issue and stop my 1st gear jam? My manual states I don't have to change it until 120K miles.... clearly this is simply wrong, at least for me. The change didn't lessen the frequency or improve it.... it STOPPED it.

I also understand oil does not wear out, per Blackstone's website, so what is going on here?

Background

I have (had) the classic "won't go into 1st gear" jam that was driving me nuts. Others have it... it appears pretty darn common... and while everyone who has the issue has their little tricks to work around it, no one has actually "fixed" the issue.... until now where I found that just changing the fluid for what is spec'd in our owner's manual simply stopped the issue. Why did I choose to change the oil despite the manual stating 120K for the change? This was a "hail Mary" pass.... I had the car at my indy for a control arm change and I had read in other posts that shifting improvements can be had by changing out the oil... so I did.

One technique I found for lessening the jam is make very left, then up shift movements and not move in an arc. Others double clutch..... whatever. Some say to adjust the cables but I found this is useless when I installed my Numeric shifter and better understood the mechanism (the transmission does the clicking, springing etc. and not the cable lengths or shifter itself).

Blackstone's claims that oil does not wear out: http://www.blackstone-labs.com/by-pa...filtration.php

Beware, ask the dealer what they use. My indy could not get me PTX and he gets his Porsche-labeled parts from a local dealership. That dealership told him they only fill with common Delvac, a G5 rated oil for track and GT3 use. My manual states only PTX, a G4.5 rated oil. I ordered 3 liters from Suncoast for $115 including shipping. Some say these oils makes a differences in shift smoothness. PTX should have better performance for those of us who run our cars in cold weather.

My owner's manual states the following: approx. 3.17 quarts / 3.0 liters transmission oil Mobilube PTX Formula A (SAE 75W-90) GL 4.5

Read more here, in particular posts by Luxter and GTGears post #17 for great information: https://rennlist.com/forums/997-foru...ynchros-2.html

So, what is going on here?

Peace
Bruce in Philly

Luxter

Hi Bruce,
Sounds like you have a very nice problem on hand.
For one, I disagree with BS's concept of oils not aging. We can talk about it until cows come home......
Second, your observations match my customers' feedback.
I would love to hear from GT Gears as well.
Cheers,
Luke

alexb76

I have some experience to share...

I had some gear change issues on track, mine was more 3rd to 2nd, and also a bit of a difficult 1st gear. I first re-adjusted the shifter cable, and it did improve going into 1st, but nothing else, then I changed my fluid to OEM fluid (this one http://www.suncoastparts.com/product/99991754600.html), and that really did the work. It really helped the shifting on the track and in general made it all smoother. So, 100% changing the transmission oil after let's say 5 years or so, does improve things.

Now, what's the PTX oil? Is that different than OEM? Probably the same, as priced similarly?

Jossue

I just replaced my Trans oil at 69k, I used Valvoline 75W90 and it is a night and day difference, I had a feeling that changing oil might improve the feel of the shifting action a little bit. I was really surprised it made this much of a difference. I do also agree that shifting in an L motion into firsts gets rid of "hard to shift" feeling. just my .2 cents

Jastx

Very interesting! Glad it solved your issue.

Philster

Could you have had a low level of lubricant and now you're spot on?

Bruce In Philly

Sure, I guess that is possible. I thought of that too and was going to have the effluent measured but it was obviously a hassle... into the big drum it went. I never had a leak spot on my floor and there were no seep stains anywhere on the underside of the engine. If it was low, it was low from the factory.

I can say it was dark amber in color and clear. Not sure what that means but ....

Peace
Bruce in Philly

997_rich

The oil is "good" for a long time per blackstone but that doesn't mean the properties don't change. The viscosity changes etc.

The root cause for the 1st gear is a semi-worn syncro. The syncro spins up the lay-shaft to the right speed so the gears can mesh.

The lay shaft is swimming in oil so the viscosity of that oil makes it easier or less easy to spin up so the gears can mesh.

Philster

Might I ask: Bruce, do you shift into first when moving and when slowing down from 2nd to 1st? The last couple of people who complained about their 1st gear and drove either a 996 or 997 would downshift into 1st from second.... say when entering a parking lot, and would proceed to putter around said lot in 1st.

Why I ask: Based on what I know and do, moving the shifter from 2nd to 1st above even 1 MPH is pretty much a no-no.

Just curious...

Ben Z

Every manual BMW I owned (5 in all) was balky shifting into 1st at a stop, so if it's a "semi-worn synchro" then BMW must install used synchros in their new transmissions My 997 is worse, but that's because of the long cables vs having the transmission right below the lever.

I'm having an oilservice soon, I'll ask about changing out the trans lube.

And this is bizarre, but I find when it balks, if I give the throttle a little rev, the lever goes right in. And I'm talking about with the clutch pedal to the floor. I have no idea why revving the engine with the clutch out would have any effect but it does.

Bruce In Philly

No, the jamming is when completely stopped.

It is possible a synchro is worn but I just don't believe it. My 2000 Boxster S, I put 197K on that 911 transmission, had its quirks too particularly when cold.. but nothing as bad as this one. I figure if I was hard on a transmission, I would have broke something in that transmission but I didn't.... I had the same clutch when the engine blew so I have no idea how much longer that clutch would have gone. I don't believe I am hard on transmissions.

There is something odd, or maybe just quirky about the 997 transmission.... the 997.2 is made by someone else... don't know if the internals are different... there are many threads on this I've read over the years. Check out this thread about the Numeric shifter.... some are seeking elimination of the quirks blaming the shifter (I did.... but not now). https://rennlist.com/forums/997-foru...-1-of-5-a.html

Peace
Bruce in Philly

malahhaor

Something similar on mine.
I have to let the clutch out just a touch and give it gas at that point it pops right in to the first. i have to let the clutch out just a tiny bit and very slowly else i miss the sweet spot and gears start grinding.
Safest thing is to pop it in to second and then in to 1st. at least for me.

malahhaor

Bruce, is this what you used?

http://www.suncoastparts.com/product/00004320420L.html

Bruce In Philly

Yep, that is the magic elixir... fixer of the broken... savior of the jammed... I read somewhere in an ancient text that is was provided to a German engineer on a mountain top by a burning pile of Continental tires. It was part of the 15... oops dropped it... 10 commandments of car care.

Peace
Bruce in Philly

malahhaor

LOL!!! Priceless reference.

I can't tell from the site, how big is the container / how many did you buy to get 3L?