Shifting problems
02-02-2010, 04:24 AM
#16
mikymu, your issue is different and well known, even on brand new cars. In order to shift from 2-3 at high rpm and high lateral loads, give your hand a 1/2 second pause in neutral and let the shifter naturally find 3rd gear. It will go right in and once you get used to it, it will become second nature. Whatever you do, don't force it, the more you relax, the more the gearbox works with you instead of against you.
for 3rd gear or is there some other benefit of a slight pause? I thought
I read somewhere that porsche transmissions behave better using a
slower shift speed.
02-02-2010, 07:31 AM
#17
Burning Brakes
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Erik@Gbox/ Paul, I hope you're wrong but we'll see. The one part that makes me hope it's not the syncros is that the shifter has gotten really notchy driving around on the street. Per Braman the cable bracket on the transmission was fine, and the cables are fine too. Apperently they have a special little tool to check the length of the cables to verify that they are within spec.
Peter (85gold), I hope to mention that today, again because the shifter feels so notchy on the street now (and it feels like it is in the shifter, not the gearbox. But I would presume that they already check that when the measured the cables unless they measured them at the gearbox instead of at the shifter.
FC Racer last time at 11K miles when the transmission (RMS) was out I had them check the clutch just because all I would have to do was pay for the plate, not the labor. The clutch was basically brand new so they reinstalled it. It now has 21K miles, but as stated before, the clutch seems to fully engage when standing still with no hint of slippage and any point. I do not know if they bled the clutch, I for sure have never done it myself.
I really appreciate the help, looks like I'm going to miss the 48 hours of Sebring, but keep them coming. Will post updates when I get them
Peter (85gold), I hope to mention that today, again because the shifter feels so notchy on the street now (and it feels like it is in the shifter, not the gearbox. But I would presume that they already check that when the measured the cables unless they measured them at the gearbox instead of at the shifter.
FC Racer last time at 11K miles when the transmission (RMS) was out I had them check the clutch just because all I would have to do was pay for the plate, not the labor. The clutch was basically brand new so they reinstalled it. It now has 21K miles, but as stated before, the clutch seems to fully engage when standing still with no hint of slippage and any point. I do not know if they bled the clutch, I for sure have never done it myself.
I really appreciate the help, looks like I'm going to miss the 48 hours of Sebring, but keep them coming. Will post updates when I get them
02-02-2010, 10:46 AM
#19
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mikymu, your issue is different and well known, even on brand new cars. In order to shift from 2-3 at high rpm and high lateral loads, give your hand a 1/2 second pause in neutral and let the shifter naturally find 3rd gear. It will go right in and once you get used to it, it will become second nature. Whatever you do, don't force it, the more you relax, the more the gearbox works with you instead of against you.
02-02-2010, 12:25 PM
#20
Drifting
You can actually shift very quickly with this transmission once you're used to it and when it's warm. I'm always amazed at how nicely it shifts when driving around the pits after a good 30min on-track session. I think the fantastic cooling keeps the box too cold on the street for smooth shifts.
I have a bunch of vids on YouTube under fcracer88 where you can see the shifts on track. I have never ground a gear on-track and can get 3rd gear 100% of the time now (as long as I'm relaxed).
02-02-2010, 01:09 PM
#21
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I am only guessing here, but I presume the 1/2 sec pause gives the engine and transmission mounts a chance to re-align as the engine torque is cut during the shift.
You can actually shift very quickly with this transmission once you're used to it and when it's warm. I'm always amazed at how nicely it shifts when driving around the pits after a good 30min on-track session. I think the fantastic cooling keeps the box too cold on the street for smooth shifts.
I have a bunch of vids on YouTube under fcracer88 where you can see the shifts on track. I have never ground a gear on-track and can get 3rd gear 100% of the time now (as long as I'm relaxed).
You can actually shift very quickly with this transmission once you're used to it and when it's warm. I'm always amazed at how nicely it shifts when driving around the pits after a good 30min on-track session. I think the fantastic cooling keeps the box too cold on the street for smooth shifts.
I have a bunch of vids on YouTube under fcracer88 where you can see the shifts on track. I have never ground a gear on-track and can get 3rd gear 100% of the time now (as long as I'm relaxed).
02-02-2010, 04:37 PM
#22
Burning Brakes
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well, braman called, cannot reproduce the problem and the factory rep has basically stated that since this is a track car and the condition is only at the track they can't do anything. Asked them to bleed the clutch as a last resort and will call Orbit to see if they can help.
02-02-2010, 06:54 PM
#23
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I thought GT3's were build for the track?!
We'll all be curious to know what the verdict is.
You brought it to the right place, no warranty, but if anyone will know it's Orbit!
We'll all be curious to know what the verdict is.
You brought it to the right place, no warranty, but if anyone will know it's Orbit!
02-02-2010, 07:20 PM
#24
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Okay guys I think I shed some light on this. You get the car over 6K after the gearbox is heated and it does not want to shift accurately. Then you back off and get the sense that it is still shifting notchy. Do I have the symptoms correct?
If so then here is the deal, you have worn out synchronizers, I think. The reason that you notice it more in the higher RPM Band is due to the addtional heat generated trying to slow or speed up the gears. You will notice that it gets a bit harder to shift into any gear from a downshift more so then an upshift as you are asking the lower gear to speed up, which is harder then catching a taller gear on the syncho.
Nothing for it but to rebuild your gearbox. I would upgrade your 3rd gear - 5th gear synchronizers with fresh steel units, and you should be fine.
I realize that this is not what you would like to hear, but this is what I think it is. You might benefit for a days worth of running if you move to a more viscious gearoil, as if you're running with synthetic, it may be too slick for the synchronizers could be causing some issues there.
I look forward to hearing if this assessment is correct, so please let me know, and feel free to contact me with any part needs, or if you would like us to rebuild your gearbox. That is what we specialize in.
I hope that this helps,
Erik Johnson
GBox Performance Transaxles
(303) 440-8899 work
(303) 895-4828 cell
If so then here is the deal, you have worn out synchronizers, I think. The reason that you notice it more in the higher RPM Band is due to the addtional heat generated trying to slow or speed up the gears. You will notice that it gets a bit harder to shift into any gear from a downshift more so then an upshift as you are asking the lower gear to speed up, which is harder then catching a taller gear on the syncho.
Nothing for it but to rebuild your gearbox. I would upgrade your 3rd gear - 5th gear synchronizers with fresh steel units, and you should be fine.
I realize that this is not what you would like to hear, but this is what I think it is. You might benefit for a days worth of running if you move to a more viscious gearoil, as if you're running with synthetic, it may be too slick for the synchronizers could be causing some issues there.
I look forward to hearing if this assessment is correct, so please let me know, and feel free to contact me with any part needs, or if you would like us to rebuild your gearbox. That is what we specialize in.
I hope that this helps,
Erik Johnson
GBox Performance Transaxles
(303) 440-8899 work
(303) 895-4828 cell
worn brass syncho on 3rd in particular - solution - replace brass synchos with steel ...
this was particularly expensive in the RSA/G50 and *may* be cheaper with the GT3 box ... if not I suggest you look for a 'core exch', find a box that has the steels and exch your for that one + cash ... it will be cheaper than the labor I believe
that is of course if PCNA wont warranty it ... which I doubt they will
good luck
02-02-2010, 08:53 PM
#25
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not that it is at all "transferable" I had exactly the same problem with the G50 on my RS America, high rpm shifts thru 3rd would grind and be notchy ... answer:
worn brass syncho on 3rd in particular - solution - replace brass synchos with steel ...
this was particularly expensive in the RSA/G50 and *may* be cheaper with the GT3 box ... if not I suggest you look for a 'core exch', find a box that has the steels and exch your for that one + cash ... it will be cheaper than the labor I believe
that is of course if PCNA wont warranty it ... which I doubt they will
good luck
worn brass syncho on 3rd in particular - solution - replace brass synchos with steel ...
this was particularly expensive in the RSA/G50 and *may* be cheaper with the GT3 box ... if not I suggest you look for a 'core exch', find a box that has the steels and exch your for that one + cash ... it will be cheaper than the labor I believe
that is of course if PCNA wont warranty it ... which I doubt they will
good luck
02-02-2010, 08:55 PM
#26
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those high rpm shifts and just wore out ...
on the upside ... the GT3 box is designed to have it's ratios etc "changed" which might imply that its easier/cheaper to work on it ... YMMV
02-03-2010, 03:48 AM
#28
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02-03-2010, 08:54 AM
#29
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Car was dropped off at Orbit yesterday. Took a quick test ride with Roger Hawley who could definitely feel that there was something wrong (unlike Braman who "could not repeat the problem"). We will see what happens. Doubt that anything will be done today since they are prepping a couple of cup cars for the 48 hours of Sebring and are also repairing the CupS that caught fire during the 17th hour of the 24 hours of Daytona but gearboxes are Roger's specialty.
02-03-2010, 12:42 PM
#30
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Mikymu- under high load rpm or g if I try to shift fast from 2-3 3rd wouldn't engage( did force it in during a ncrc race and popped the shift linkage). But if slight pause then no issue. I don't get ne grinding though. Mike