Tranny Oil Condition
03-22-2012 | 01:08 PM
#17
Admin
Lifetime Rennlist
Member
Lifetime Rennlist
Member
Joined: Dec 2001
Posts: 11,010
Likes: 127
From: Athens
A working LSD, be it one with our clutches in it, or Cup Car clutches, raises the gearbox temps on average 20 degrees.
I recommend never going over 15k mi on the service interval on these gearboxes. Furthermore, I say count every track day as 2500 mi. 6 days on the track and you're due to change the oil.
The other thing that I have seen with the 997 variant GT3 and GT2s is that cars that were tracked with the anemic stock clutch packs in them, they are getting really hot. This is because of the fact that the clutches are not locking and just spinning up against each other. This is a picture of the friction discs out of Mo's GT2 LSD which if memory serves only had 5000mi on it when he sent it to me.
Like many of the 997 variant LSDs that have come through here the outside case of the LSD was actually coked with burnt on oil. That's right. There was oil coked onto the differential housing. These gearboxes are getting smoking hot on track.
I recommend never going over 15k mi on the service interval on these gearboxes. Furthermore, I say count every track day as 2500 mi. 6 days on the track and you're due to change the oil.
The other thing that I have seen with the 997 variant GT3 and GT2s is that cars that were tracked with the anemic stock clutch packs in them, they are getting really hot. This is because of the fact that the clutches are not locking and just spinning up against each other. This is a picture of the friction discs out of Mo's GT2 LSD which if memory serves only had 5000mi on it when he sent it to me.
Like many of the 997 variant LSDs that have come through here the outside case of the LSD was actually coked with burnt on oil. That's right. There was oil coked onto the differential housing. These gearboxes are getting smoking hot on track.
Solid advice.
Perhaps, another factor for added stress and more frequent oil changes is a shorter R&P.
BTW 6 Cup cars had a recommended replacement of the (slightly shorter than the RS / 4 one) R&P after 8000klm!
I was doing the oils every 10k and dropped it to 5 now.
03-22-2012 | 08:09 PM
#23
Racer
Joined: Apr 2010
Posts: 296
Likes: 157
Are some of your shifting problems due to the crappy shifter cables? I have 2-3, 4-3 shift problems all the time (usually only when there are some lateral g's involved); however I'm almost certain it's cable related. I will be installing the motorsport shift cables which should rectify the shift issues hopefully.
Just had my tranny oil changed but didn't ask what it looked like. Even the first track day out this last weekend I still had shifting issues so I really don't think (in my case) it's related to the fluid.
JJ
Just had my tranny oil changed but didn't ask what it looked like. Even the first track day out this last weekend I still had shifting issues so I really don't think (in my case) it's related to the fluid.
JJ
03-22-2012 | 11:30 PM
#26
Racer
Joined: Apr 2009
Posts: 279
Likes: 3
I went to Cup Car cables to address difficult shifting from 2nd to 3rd accelerating out of low speed corners. The Cup cables and all metal end fittings definitely help but they bring a lot of noise into the cabin which may bother you if you use on the street. I'm happy with the improvement. I have Guard LSD, change tranny oil every 7-10 track days/once a month in season , the old oil is always black.
Are some of your shifting problems due to the crappy shifter cables? I have 2-3, 4-3 shift problems all the time (usually only when there are some lateral g's involved); however I'm almost certain it's cable related. I will be installing the motorsport shift cables which should rectify the shift issues hopefully.
Just had my tranny oil changed but didn't ask what it looked like. Even the first track day out this last weekend I still had shifting issues so I really don't think (in my case) it's related to the fluid.
JJ
Just had my tranny oil changed but didn't ask what it looked like. Even the first track day out this last weekend I still had shifting issues so I really don't think (in my case) it's related to the fluid.
JJ
03-23-2012 | 12:59 AM
#27
Nordschleife Master
Joined: Dec 2008
Posts: 7,342
Likes: 294
From: Florida
I went to Cup Car cables to address difficult shifting from 2nd to 3rd accelerating out of low speed corners. The Cup cables and all metal end fittings definitely help but they bring a lot of noise into the cabin which may bother you if you use on the street. I'm happy with the improvement. I have Guard LSD, change tranny oil every 7-10 track days/once a month in season , the old oil is always black.
Are some of your shifting problems due to the crappy shifter cables? I have 2-3, 4-3 shift problems all the time (usually only when there are some lateral g's involved); however I'm almost certain it's cable related. I will be installing the motorsport shift cables which should rectify the shift issues hopefully.
Just had my tranny oil changed but didn't ask what it looked like. Even the first track day out this last weekend I still had shifting issues so I really don't think (in my case) it's related to the fluid.
JJ
Just had my tranny oil changed but didn't ask what it looked like. Even the first track day out this last weekend I still had shifting issues so I really don't think (in my case) it's related to the fluid.
JJ
It is a heat issue in the transmission
03-23-2012 | 09:56 AM
#28
Rennlist Member
Joined: Oct 2003
Posts: 5,110
Likes: 820
From: 92 miles from Sebring
More friction = higher temps.
More effective fluid to bring the friction down ?
Free movement is colder, colder = less strees
Colder = more power to the wheels.
BTW I didn't use Delvac on the GTTWICE. Peter (Farmer) gave me a great tip of Synergyn Fluid.
Notchy when cold, but really good when hot.
More effective fluid to bring the friction down ?
Free movement is colder, colder = less strees
Colder = more power to the wheels.
BTW I didn't use Delvac on the GTTWICE. Peter (Farmer) gave me a great tip of Synergyn Fluid.
Notchy when cold, but really good when hot.
Peter
03-23-2012 | 01:16 PM
#29
Nordschleife Master
Joined: Oct 2009
Posts: 5,167
Likes: 126
From: Loveland, CO
BTW, I know that this is going to be met with some unhappy faces, but one of the realities of how you guys chose to use your cars is accelerated wear and tear. While I would expect a street driven GT3 to go 10 years between gearbox rebuilds, I would only expect yours to go 2-3 years with a bunch of track days on them. Synchros and bearings are not indestructible and while you guys are probably running 8/10ths of what a race car would run, you're also probably stressing it 300% more than a street car would be stressed.
People always balk when I advise them that if they are going to put in one of our super short 3rd gears that they need to time them and be ready to go back in there and replace it in 30 or 40 hours. The response is usually, "But I only DE my car." Doesn't matter. Track time is track time and 5000mi with an average speed of 90mph is 55.5 hours. If it was my personal car, I would be budgetting to go in and refresh the thing every 60 hours at a maximum and more often if you regear it or run a short ratio ring and pinion. Let's not forget that the short ratio ring and pinion makes every single gear spin more rotations per hour of use. It is a wear accelerator on everything and not just a service item all by itself. You do have to pay to play this game of fools...
People always balk when I advise them that if they are going to put in one of our super short 3rd gears that they need to time them and be ready to go back in there and replace it in 30 or 40 hours. The response is usually, "But I only DE my car." Doesn't matter. Track time is track time and 5000mi with an average speed of 90mph is 55.5 hours. If it was my personal car, I would be budgetting to go in and refresh the thing every 60 hours at a maximum and more often if you regear it or run a short ratio ring and pinion. Let's not forget that the short ratio ring and pinion makes every single gear spin more rotations per hour of use. It is a wear accelerator on everything and not just a service item all by itself. You do have to pay to play this game of fools...
03-23-2012 | 05:19 PM
#30
Burning Brakes
Joined: Oct 2005
Posts: 1,074
Likes: 0
From: FL
I agree, DE cars are tracked hard. I am surprised GT3s can take that much and still run during the week days. Now, is it safe to assume base on this that transmissions are the first items to require maintance?