MT Transmission gritty shifting woes
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Joined: Apr 2015
Posts: 69
Likes: 3
From: NJ
I had an issue with my gearbox few months back (10 c4s).
It started out as a sometime crunchy shift into second to randomly not going into first at red light.
Insisted on a test drive with a master tech and he was able to reproduce after a couple of miles of driving. He was a little cagey but acknowledged the problem but insisted that it could be shifter cable or synchro. they opened things up and after 2 weeks ordered a new box from germany. think the dealer had to exhaust all other options before calling the cpo for a new tranny.
Got a new tranny under CPO. Took a month but worth the wait.
Good luck with your test drive
It started out as a sometime crunchy shift into second to randomly not going into first at red light.
Insisted on a test drive with a master tech and he was able to reproduce after a couple of miles of driving. He was a little cagey but acknowledged the problem but insisted that it could be shifter cable or synchro. they opened things up and after 2 weeks ordered a new box from germany. think the dealer had to exhaust all other options before calling the cpo for a new tranny.
Got a new tranny under CPO. Took a month but worth the wait.
Good luck with your test drive
Thread Starter
Racer
Joined: May 2015
Posts: 259
Likes: 12
*UPDATE*
Today, the "Ambassador", tech, and master tech all drove the car and declared that the notchiness is within norm.
So I ordered 2 gallons of Mobilube PTX from Suncoast since it is developed specifically for the porsche synchros, and it seems to have helped here:
https://rennlist.com/forums/997-foru...-gear-oil.html
I'll update once it's in.
Today, the "Ambassador", tech, and master tech all drove the car and declared that the notchiness is within norm.
So I ordered 2 gallons of Mobilube PTX from Suncoast since it is developed specifically for the porsche synchros, and it seems to have helped here:
https://rennlist.com/forums/997-foru...-gear-oil.html
I'll update once it's in.
Rennlist Member
Joined: Jul 2014
Posts: 1,877
Likes: 343
From: deine Mutter
*UPDATE*
Today, the "Ambassador", tech, and master tech all drove the car and declared that the notchiness is within norm.
So I ordered 2 gallons of Mobilube PTX from Suncoast since it is developed specifically for the porsche synchros, and it seems to have helped here:
https://rennlist.com/forums/997-foru...-gear-oil.html
I'll update once it's in.
Today, the "Ambassador", tech, and master tech all drove the car and declared that the notchiness is within norm.
So I ordered 2 gallons of Mobilube PTX from Suncoast since it is developed specifically for the porsche synchros, and it seems to have helped here:
https://rennlist.com/forums/997-foru...-gear-oil.html
I'll update once it's in.
For the time being I skip the 2nd while the car is not up to temp.
look forward to your update
Racer
Joined: Sep 2013
Posts: 264
Likes: 7
From: Stuttgart, Germany
I also have similar probs with my 6MT:
Standing at red light, can't put it into 1st, just blocked (happens 20% of time, cold or warm)
Shifting from 1st to 2nd feels notchy but no poping out.
My indy changed the gear fluid and checked for shavings in the old fluid (found minor particles). Situation did not improve after change. Indy said to drive snot out of it and then tear tranny down and replace synchros.
Regards,
CF
Standing at red light, can't put it into 1st, just blocked (happens 20% of time, cold or warm)
Shifting from 1st to 2nd feels notchy but no poping out.
My indy changed the gear fluid and checked for shavings in the old fluid (found minor particles). Situation did not improve after change. Indy said to drive snot out of it and then tear tranny down and replace synchros.
Regards,
CF
Racer
Joined: Jun 2011
Posts: 484
Likes: 3
From: NorCal
I have never driven a 996/997 MT that went into first smoothly and reliably. Every 996/997 MT I have driven has a noticeable hitch or notch when shifting from first to second. Admittedly my sample size is small (~10).
Popping out of second sounds like a synchro problem unless you are causing the car to lurch via clutch or gas pedal for some reason.
Popping out of second sounds like a synchro problem unless you are causing the car to lurch via clutch or gas pedal for some reason.
Pro
Joined: Mar 2005
Posts: 684
Likes: 5
From: West Coast Canada
that is what they told me as well at my local Porsche dealer. I have the Numeric Cables and Shifter and the problems started with the 2nd gear after I got these installed. So I am not really buying it. Mine is pretty much likes yours only happens when cold. Down shifting into 2nd it either does not got in or popes out. When warm no problem at all. I am interested to see if the PTX will help if it does I will try this next.
For the time being I skip the 2nd while the car is not up to temp.
look forward to your update
For the time being I skip the 2nd while the car is not up to temp.
look forward to your update
Cheers
Rennlist Member
Joined: Jul 2014
Posts: 1,877
Likes: 343
From: deine Mutter
This Dealership purchased two Porsche Dealerships and did not do the original install. However the Mechanic that worked for Plaza Motors that did the install works now for Porsche of St. Louis.
I may see if the Local Indy can look at this. The issue is that all of these places are about 1.5 hr drive each way.
thanks for your reply
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Racer
Joined: Sep 2013
Posts: 264
Likes: 7
From: Stuttgart, Germany
As Bruce already pointed out it's not an issue with the cables. I adjusted mine multiple times and it made no difference at all. I even put in a GT3 shift block and again no change whatsoever. If the synchros are worn then nothing will remedy the problems caused by that other than replacing the synchros.
Instructor
Joined: Mar 2015
Posts: 178
Likes: 1
I have never driven a 996/997 MT that went into first smoothly and reliably. Every 996/997 MT I have driven has a noticeable hitch or notch when shifting from first to second. Admittedly my sample size is small (~10).
Popping out of second sounds like a synchro problem unless you are causing the car to lurch via clutch or gas pedal for some reason.
Popping out of second sounds like a synchro problem unless you are causing the car to lurch via clutch or gas pedal for some reason.
Rennlist Member
Joined: Nov 2009
Posts: 3,168
Likes: 538
From: PNW
I have found that mine is noticeably notch when cold. Once things warm up it seems to like shifting under load and above 5k with deliberate movement. Not slamming through the gears, just changing with purpose. As far as the not going into first at a stop light... I've found a decent work around... As I'm coming to a stop I push in the clutch and rev the engine a bit, and just before it comes to a complete stop, I slide it into first and hold it until the car settles at stop. Then you should feel it slide right out. Release the clutch and wait for the light.
Instructor
Joined: Nov 2010
Posts: 211
Likes: 3
I have had my 997.2 since new and also occasionally have difficulty shifting into first and experience a crunch when shifting from 1st to 2nd when cold. Once in awhile I get a 'grunch' with high RPM shifts from 1st to 2nd even when warm. ( I think this is the synchro's ) I believe all of this is fairly normal with this transmission.
I am going to try switching to Mobilube PTX also may start double clutching my 1st to 2nd shifts.
I am going to try switching to Mobilube PTX also may start double clutching my 1st to 2nd shifts.
Racer
Joined: Jun 2011
Posts: 484
Likes: 3
From: NorCal
I have had my 997.2 since new and also occasionally have difficulty shifting into first and experience a crunch when shifting from 1st to 2nd when cold. Once in awhile I get a 'grunch' with high RPM shifts from 1st to 2nd even when warm. ( I think this is the synchro's ) I believe all of this is fairly normal with this transmission.
I am going to try switching to Mobilube PTX also may start double clutching my 1st to 2nd shifts.
I am going to try switching to Mobilube PTX also may start double clutching my 1st to 2nd shifts.
I don't think this is unique to Porsche. I have owned 15 cars with manual transmissions and all them exhibited related behaviors--to varying degrees.
I suppose this due to the fact that virtually all transmissions are either designed by, built by, or have their origin with ZF, Getrag, Aisin, or BorgWarner. And I think there is plenty of technology sharing between those manufacturers.
RL Community Team
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Joined: Dec 2012
Posts: 7,663
Likes: 2,603
From: Atlanta
Mobilube PTX GL 4.5 NOTE: GL 4.5
First off.... I can't believe these transmissions are this sensitive to oil type but it appears to be so. The issue appears to be the GL 4.5 rating which is related to friction modifiers... or the amount of slipperyness. This is not a weight issue as the GL rating is another denotation of oil characteristics. This is important because our transmissions are transaxles and not pure transmissions or differentials. Again, I am just pulling in stuff I read on these forums.
Read this thread and in particular, post #17 by GTgears.
https://rennlist.com/forums/997-foru...-synchros.html
Another:
https://www.lubrizol.com/DrivelineAd...arOil/GL5.html - Describes each GL rating and note there is NO 4.5
http://www.widman.biz/uploads/Transaxle_oil.pdf Describes the protection of differing components of GL 4 and GL 5
If you google GL 4.5 and the oils weight, you don't come up with anything. It appears that this Mobilube stuff is specially formulated for our transmissions. Why? Well I am tired of second guessing Porsche's recommendations. That is what Porsche denotes in our manuals, and therefore that is what I will use. And guess what? It worked.
As others have noted, our transmissions are quirky. But still, it should not jam just going into 1st gear. Before you freak out that your transmission is failing, I recommend doing these two things in this order:
1) Shift in straight left-right, and front-back lines. Do not move in an arc. Straight lines will move one cable and therefore one internal mechanism at a time. Moving in an arc moves both cables at the same time and therefore, notchy or not smooth shifting.
2) Change your oil using exactly what Porsche recommends.
Peace
Bruce in Philly
First off.... I can't believe these transmissions are this sensitive to oil type but it appears to be so. The issue appears to be the GL 4.5 rating which is related to friction modifiers... or the amount of slipperyness. This is not a weight issue as the GL rating is another denotation of oil characteristics. This is important because our transmissions are transaxles and not pure transmissions or differentials. Again, I am just pulling in stuff I read on these forums.
Read this thread and in particular, post #17 by GTgears.
https://rennlist.com/forums/997-foru...-synchros.html
Another:
https://www.lubrizol.com/DrivelineAd...arOil/GL5.html - Describes each GL rating and note there is NO 4.5
http://www.widman.biz/uploads/Transaxle_oil.pdf Describes the protection of differing components of GL 4 and GL 5
If you google GL 4.5 and the oils weight, you don't come up with anything. It appears that this Mobilube stuff is specially formulated for our transmissions. Why? Well I am tired of second guessing Porsche's recommendations. That is what Porsche denotes in our manuals, and therefore that is what I will use. And guess what? It worked.
As others have noted, our transmissions are quirky. But still, it should not jam just going into 1st gear. Before you freak out that your transmission is failing, I recommend doing these two things in this order:
1) Shift in straight left-right, and front-back lines. Do not move in an arc. Straight lines will move one cable and therefore one internal mechanism at a time. Moving in an arc moves both cables at the same time and therefore, notchy or not smooth shifting.
2) Change your oil using exactly what Porsche recommends.
Peace
Bruce in Philly
Last edited by Bruce In Philly; Nov 15, 2015 at 01:44 PM.