Clutches Slipping Past 5k RPM - Professional or Experienced Advice Please!
09-01-2011, 10:57 AM
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Launching!
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Clutches Slipping Past 5k RPM - Professional or Experienced Advice Please! Background: Have a 98 z28 with a ls2/4l60e. Car has full boltons, cam, supporting valvetrain mods, suspension, stall, etc..
I have a good understanding of how engines work, but trannys, not so much, so I'm looking for more knowledge, understanding, and expertise..
I DD this car and have put almost 20k miles on it in nearly 2 years. When I bought it the tranny was pretty fresh, around 5k on tranny build with a 3500 Stall. So its got around 25k miles on it. It was aparantly built by Kurt Dillinger out of Orlando FL and is rated at 650 ft lbs.
So the dyno recently confirmed the clutches are slipping past 5,000 RPM. (Ever since the first time I ran the car WOT through the gears it has trouble on the 2-3 shift and will limiter bounce untill i back out of the throttle. I always thought the shiftpoint was too high and kind of ignored this because I thought it was the tune and RARELY go WOT or even have the room to run the car through those gears. It seems like it dosn't do it everytime, but I think that is me backing off through the shift out of habit).
I compared the torque curve on my dyno sheet from the previous summer and it is strikingly similar, only smoother. Now that I know its slipping I can definitely feel it fall on its face a bit in the high rpm.
I'm sure there are no hard parts broken, so:
My questions are:
1. Do you think this means my clutch has been slipping since I got the car?
2. What all will I need to buy to replace the clutches?
3. What should the clutches and other needed parts cost? (estimated by tuner at around $800)
4. If I have someone do the work, how much would a quality job cost just for clutches? (estimated by tuner at $1000 to drop it, change parts, and reinstall) I was thinking if it comes down to it I would try to save money and do the drop and install myself (hell maybe even the whole job if its not too hard, I do know 2 tranny guys, just scared to get into worse tranny problems)
I really appreciate any advice and Thanks in advance guys!
ALSO,
Another problem I've always had:
When driving the car, the TC will pop/knock when full lockup engages at low speeds around 40-45mph (sounds like its comming from the rear end, maybe a U-joint?)
And,
TC in full lock up, I'm getting a knocking/tapping noise (sounds like its from either the trans or the rear end) when the car starts do decelerate while still in lockup. For example, on the highway on cruise control at 70, I will go over an overpass and on the downslope the car will get this noise/knock/tapping while the car is "coasting" (still with cruise on) down the slope, but when the road evens out and the gas comes back on its stops. My best way of describing it is its like there is slack between gear teeth somewhere and as the car slows the teeth bind, but once back in the gas the gears begin to "rest properly" and push forward, stopping the noise/tap/vibration/knock/etc.
Is this a converter issue or what?
Thanks again for the info!!
I have a good understanding of how engines work, but trannys, not so much, so I'm looking for more knowledge, understanding, and expertise..
I DD this car and have put almost 20k miles on it in nearly 2 years. When I bought it the tranny was pretty fresh, around 5k on tranny build with a 3500 Stall. So its got around 25k miles on it. It was aparantly built by Kurt Dillinger out of Orlando FL and is rated at 650 ft lbs.
So the dyno recently confirmed the clutches are slipping past 5,000 RPM. (Ever since the first time I ran the car WOT through the gears it has trouble on the 2-3 shift and will limiter bounce untill i back out of the throttle. I always thought the shiftpoint was too high and kind of ignored this because I thought it was the tune and RARELY go WOT or even have the room to run the car through those gears. It seems like it dosn't do it everytime, but I think that is me backing off through the shift out of habit).
I compared the torque curve on my dyno sheet from the previous summer and it is strikingly similar, only smoother. Now that I know its slipping I can definitely feel it fall on its face a bit in the high rpm.
I'm sure there are no hard parts broken, so:
My questions are:
1. Do you think this means my clutch has been slipping since I got the car?
2. What all will I need to buy to replace the clutches?
3. What should the clutches and other needed parts cost? (estimated by tuner at around $800)
4. If I have someone do the work, how much would a quality job cost just for clutches? (estimated by tuner at $1000 to drop it, change parts, and reinstall) I was thinking if it comes down to it I would try to save money and do the drop and install myself (hell maybe even the whole job if its not too hard, I do know 2 tranny guys, just scared to get into worse tranny problems)
I really appreciate any advice and Thanks in advance guys!
ALSO,
Another problem I've always had:
When driving the car, the TC will pop/knock when full lockup engages at low speeds around 40-45mph (sounds like its comming from the rear end, maybe a U-joint?)
And,
TC in full lock up, I'm getting a knocking/tapping noise (sounds like its from either the trans or the rear end) when the car starts do decelerate while still in lockup. For example, on the highway on cruise control at 70, I will go over an overpass and on the downslope the car will get this noise/knock/tapping while the car is "coasting" (still with cruise on) down the slope, but when the road evens out and the gas comes back on its stops. My best way of describing it is its like there is slack between gear teeth somewhere and as the car slows the teeth bind, but once back in the gas the gears begin to "rest properly" and push forward, stopping the noise/tap/vibration/knock/etc.
Is this a converter issue or what?
Thanks again for the info!!
09-01-2011, 10:59 AM
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Launching!
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Note: as far as the knocking noise:
This noise is not the "box of rocks" noise that is caused by loose e-brake shoes. Already have tightened that a couple months ago
This noise is not the "box of rocks" noise that is caused by loose e-brake shoes. Already have tightened that a couple months ago
09-01-2011, 01:27 PM
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That sounds like peak motor torque exceeds clutch holding
capacity. I would look at the commanded force motor
current first thing, it had better be down to near zero.
But your first episode may have glazed the frictions and
then no amount of pressure may hold anymore.
Assuming this is still PCM controlled and not vac mod.
Might be worth getting a line gauge on it to see if any
mechanical pressure problem is underneath it all.
capacity. I would look at the commanded force motor
current first thing, it had better be down to near zero.
But your first episode may have glazed the frictions and
then no amount of pressure may hold anymore.
Assuming this is still PCM controlled and not vac mod.
Might be worth getting a line gauge on it to see if any
mechanical pressure problem is underneath it all.
09-02-2011, 10:30 AM
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That sounds like peak motor torque exceeds clutch holding
capacity. I would look at the commanded force motor
current first thing, it had better be down to near zero.
But your first episode may have glazed the frictions and
then no amount of pressure may hold anymore.
Assuming this is still PCM controlled and not vac mod.
Might be worth getting a line gauge on it to see if any
mechanical pressure problem is underneath it all.
capacity. I would look at the commanded force motor
current first thing, it had better be down to near zero.
But your first episode may have glazed the frictions and
then no amount of pressure may hold anymore.
Assuming this is still PCM controlled and not vac mod.
Might be worth getting a line gauge on it to see if any
mechanical pressure problem is underneath it all.
Will I need some software (efi live/hp tuners) to check force motor current?
I am assuming it is still PCM controlled, Is there a way to tell?
09-02-2011, 11:18 AM
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HPTuners, EFILive or even a borrowed AutoTAP will
do for scanning.
If there's no vacuum line routed from engine bay to
trans, it would be still PCM controlled. Some builders
swap to vacuum modulated to eliminate tune stupidity
as a cause of death. I wouldn't know how to tell by
looking in the body with the pan off but I bet that
would be obvious too. Speaking of which, what's
laying in the bottom of the pan and how much of it?
do for scanning.
If there's no vacuum line routed from engine bay to
trans, it would be still PCM controlled. Some builders
swap to vacuum modulated to eliminate tune stupidity
as a cause of death. I wouldn't know how to tell by
looking in the body with the pan off but I bet that
would be obvious too. Speaking of which, what's
laying in the bottom of the pan and how much of it?
09-02-2011, 06:20 PM
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HPTuners, EFILive or even a borrowed AutoTAP will
do for scanning.
If there's no vacuum line routed from engine bay to
trans, it would be still PCM controlled. Some builders
swap to vacuum modulated to eliminate tune stupidity
as a cause of death. I wouldn't know how to tell by
looking in the body with the pan off but I bet that
would be obvious too. Speaking of which, what's
laying in the bottom of the pan and how much of it?
do for scanning.
If there's no vacuum line routed from engine bay to
trans, it would be still PCM controlled. Some builders
swap to vacuum modulated to eliminate tune stupidity
as a cause of death. I wouldn't know how to tell by
looking in the body with the pan off but I bet that
would be obvious too. Speaking of which, what's
laying in the bottom of the pan and how much of it?
Fluid in that thing is clean as can be, always have kept it very very fresh.
Its probably been less than 8k miles on the current fluid. I've changed the fluid 2 times and both times it has been prtty damn clean with minimal but expected clutch material.
Here is my dyno sheet:
Run 1 unadjusted after FAST intake
Run 2 adjusted but not revving out as high because he said clutch was slipping
Would i still make 427 rw on a slipping clutch? Yeah torue is only 371, but its always been significantly lower with this car. Intake and TB picked up 37 rwhp and only 11rwtq.
A buddy of mine thinks the numbers are high for a slipping clutch and thinks my shift mph may be off caushing the rev limiter bounching on the 2-3 shift until i reach the desired speed.
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10-18-2011, 08:25 AM
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So after checking out the rear end and driveshaft I have found nothing obviously wrong. Ujoints appear fine, nice and tight.
Anyone know how much play or slop should be in the rear end. With the car in neutral I twist the driveshaft and it has about 2mm of play. Is that too much?
Anyone know how much play or slop should be in the rear end. With the car in neutral I twist the driveshaft and it has about 2mm of play. Is that too much?
10-18-2011, 09:05 AM
#10
You've asked a lot of questions here buddy! But it's a terrific thread. You seem very informed and are not afraid to ask the questions, then do the research. Good for you, that's how we all learn my friend.
Jimmy is spot on when asking about Force Motor commanded values at WOT. The Force Motor is also known as a Electronic Pressure Control Solenoid (EPC). It is a PCM driven component that increases and decreases line pressure based on torque loads. SO, when your Tuner was tinkering with your tune, if he did not manage those tables properly then it's quite possible that this is why your nice transmission is slipping. He should have been able to show you that the EPC commanded value was zero at WOT and right then and there you would have had the answer to your question. A good Tuner would have pulled those tables up immediately upon seeing that spike on the dyno, and he would not have continued the pull once he recognized the clutches weren't holding.
Think of the EPC as the Throttle Valve cable on the 700R4 transmission. The cable moves in direct relation to the throttle input.
If your tranny has missed the 2/3 shift at WOT many times at all then the 3/4 clutches are glazed at best, burnt at worst.
As far as the clunking that you are feeling when you are coasting, that is a Tune issue as well. You're feeling what is commonly referred to as Cam Surge. Basically, it the exact same condition that can be felt in a manual transmission vehicle when it is in too high of a gear and the throttle is released and reapplied. Point is, your torque converter is staying locked up at zero throttle and you are feeling the car rock back and forth on the ring and pinion.
If you would like to discuss your issues in great detail feel free to give me a call.
g
Jimmy is spot on when asking about Force Motor commanded values at WOT. The Force Motor is also known as a Electronic Pressure Control Solenoid (EPC). It is a PCM driven component that increases and decreases line pressure based on torque loads. SO, when your Tuner was tinkering with your tune, if he did not manage those tables properly then it's quite possible that this is why your nice transmission is slipping. He should have been able to show you that the EPC commanded value was zero at WOT and right then and there you would have had the answer to your question. A good Tuner would have pulled those tables up immediately upon seeing that spike on the dyno, and he would not have continued the pull once he recognized the clutches weren't holding.
Think of the EPC as the Throttle Valve cable on the 700R4 transmission. The cable moves in direct relation to the throttle input.
If your tranny has missed the 2/3 shift at WOT many times at all then the 3/4 clutches are glazed at best, burnt at worst.
As far as the clunking that you are feeling when you are coasting, that is a Tune issue as well. You're feeling what is commonly referred to as Cam Surge. Basically, it the exact same condition that can be felt in a manual transmission vehicle when it is in too high of a gear and the throttle is released and reapplied. Point is, your torque converter is staying locked up at zero throttle and you are feeling the car rock back and forth on the ring and pinion.
If you would like to discuss your issues in great detail feel free to give me a call.
g
10-18-2011, 12:50 PM
#11
Anythings possible but it would seem if its slipping cluthes particulary the 3-4 (3rd) clutch set after only a couple times there would be no third gear.If your sure you are no cavating the pan at WOT (might try adding about 1/2 quart to see) then perhaps you are blowing through the converter, When you were on the dyno was the converter locked or unlocked? The HP numbers you are giving see like a high yeild for a car with a slipping trans.
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10-20-2011, 06:55 AM
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You've asked a lot of questions here buddy! But it's a terrific thread. You seem very informed and are not afraid to ask the questions, then do the research. Good for you, that's how we all learn my friend.
Jimmy is spot on when asking about Force Motor commanded values at WOT. The Force Motor is also known as a Electronic Pressure Control Solenoid (EPC). It is a PCM driven component that increases and decreases line pressure based on torque loads. SO, when your Tuner was tinkering with your tune, if he did not manage those tables properly then it's quite possible that this is why your nice transmission is slipping. He should have been able to show you that the EPC commanded value was zero at WOT and right then and there you would have had the answer to your question. A good Tuner would have pulled those tables up immediately upon seeing that spike on the dyno, and he would not have continued the pull once he recognized the clutches weren't holding.
Think of the EPC as the Throttle Valve cable on the 700R4 transmission. The cable moves in direct relation to the throttle input.
If your tranny has missed the 2/3 shift at WOT many times at all then the 3/4 clutches are glazed at best, burnt at worst.
As far as the clunking that you are feeling when you are coasting, that is a Tune issue as well. You're feeling what is commonly referred to as Cam Surge. Basically, it the exact same condition that can be felt in a manual transmission vehicle when it is in too high of a gear and the throttle is released and reapplied. Point is, your torque converter is staying locked up at zero throttle and you are feeling the car rock back and forth on the ring and pinion.
If you would like to discuss your issues in great detail feel free to give me a call.
g
Jimmy is spot on when asking about Force Motor commanded values at WOT. The Force Motor is also known as a Electronic Pressure Control Solenoid (EPC). It is a PCM driven component that increases and decreases line pressure based on torque loads. SO, when your Tuner was tinkering with your tune, if he did not manage those tables properly then it's quite possible that this is why your nice transmission is slipping. He should have been able to show you that the EPC commanded value was zero at WOT and right then and there you would have had the answer to your question. A good Tuner would have pulled those tables up immediately upon seeing that spike on the dyno, and he would not have continued the pull once he recognized the clutches weren't holding.
Think of the EPC as the Throttle Valve cable on the 700R4 transmission. The cable moves in direct relation to the throttle input.
If your tranny has missed the 2/3 shift at WOT many times at all then the 3/4 clutches are glazed at best, burnt at worst.
As far as the clunking that you are feeling when you are coasting, that is a Tune issue as well. You're feeling what is commonly referred to as Cam Surge. Basically, it the exact same condition that can be felt in a manual transmission vehicle when it is in too high of a gear and the throttle is released and reapplied. Point is, your torque converter is staying locked up at zero throttle and you are feeling the car rock back and forth on the ring and pinion.
If you would like to discuss your issues in great detail feel free to give me a call.
g
To check the commanded values for the Force Motor/EPC all I have to do would be look in the tune, correct? If so I will just call and have him look into it.
I'm suprised to hear you can make a tranny slip just with a faulty tune, didnt know that. I think its very possible he screwed up in the tune. I know he CAN tune cars well, but I dont feel like he takes the time to do so. I just dont know what all goes into perfecting the tune or what should be done and when. THat just makes it easy to get a BS tune put on my car. So I'm learning.
But the fact that when he saw the spike in the dyno and didn't (or at least i dont think he did) check on those tables dosn't give me any added confidence in him..
And the trans has missed the shift MANY times, but I dont allow it intentionally. But if this can be due to the tune being goofed up I'm not convinced its slipping because the car still pulls very hard.
As for the cam surge, next time I'm at the tuner I'll have it moved up and see if that works. Is it normal for a TC to be set up so it unlocks when the gas is fully let off? That is what mine does unless I'm traveling at highway speeds.
I may call you if I continue to have trouble. I really appreciate all your advice Gilbert
Anythings possible but it would seem if its slipping cluthes particulary the 3-4 (3rd) clutch set after only a couple times there would be no third gear.If your sure you are no cavating the pan at WOT (might try adding about 1/2 quart to see) then perhaps you are blowing through the converter, When you were on the dyno was the converter locked or unlocked? The HP numbers you are giving see like a high yeild for a car with a slipping trans.
And I may try to add some fluid and see if there is a change, but I do keep the fliud really clean and fresh and if anything it is a bit on the full side.
On the dyno to my knowledge the TC was unlocked. It dosn't fully lock until the car has gone through 4th gear.
Thanks for the info you guys, tech is such an awesome resource
10-20-2011, 08:13 AM
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Let me touch on your coasting racket you are having. The advantage of my advice is A. I have the same problem as you (but at lower speeds), B. I built the rear end, then coincidentally have rechecked it since, and C. am familiar with HPTuners. Mine was never really an issue until I swapped in a different cam. I don't think the tune was very good in the lower rpms (we didn't spend much time tuning it there). When I would cruise down the neighborhood streets rpm would fall very low, think 1000-1500. When I let off the gas or only lightly applied it, I would get the same banging in the ring and pinion like you are describing. I suspected my backlash had opened up since installing them R+P a few thousand miles ago. So I opened it up and measured....it was right at .007 where I left it when I first installed the gears. So it wasn't a rear end problem. As soon as the cam surge goes away (rpm wise), the clanking disappears. So, the solution to the problem is A. fix the cam surge down to a reasonable rpm then B. make sure your tranny keeps you above that point so you avoid the surging and the clanking that follows. It's basically caused from loading the engine too low in the rpm band for it to run smooth. However, I'm talking about 20-30 mph in my case. With yours being at a higher speed, I would think yours could benefit for some off/light throttle tuning in these areas to smooth the engine out, and your trans settings may be perfectly fine. Also, for the 2/3, you should verify the shift is being commanded correctly. I, like you, had a very good tuner, but felt like the time wasn't taken to fix a 2/3 shift problem like yours during tuning. I ended up getting HPTuners, and after reading some, found my problem immediately. It took a simple correction in the commanded mph table at WOT, and my 2/3 missed shifting has vanished.
10-20-2011, 09:40 AM
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Let me touch on your coasting racket you are having. The advantage of my advice is A. I have the same problem as you (but at lower speeds), B. I built the rear end, then coincidentally have rechecked it since, and C. am familiar with HPTuners. Mine was never really an issue until I swapped in a different cam. I don't think the tune was very good in the lower rpms (we didn't spend much time tuning it there). When I would cruise down the neighborhood streets rpm would fall very low, think 1000-1500. When I let off the gas or only lightly applied it, I would get the same banging in the ring and pinion like you are describing. I suspected my backlash had opened up since installing them R+P a few thousand miles ago. So I opened it up and measured....it was right at .007 where I left it when I first installed the gears. So it wasn't a rear end problem. As soon as the cam surge goes away (rpm wise), the clanking disappears. So, the solution to the problem is A. fix the cam surge down to a reasonable rpm then B. make sure your tranny keeps you above that point so you avoid the surging and the clanking that follows. It's basically caused from loading the engine too low in the rpm band for it to run smooth. However, I'm talking about 20-30 mph in my case. With yours being at a higher speed, I would think yours could benefit for some off/light throttle tuning in these areas to smooth the engine out, and your trans settings may be perfectly fine. Also, for the 2/3, you should verify the shift is being commanded correctly. I, like you, had a very good tuner, but felt like the time wasn't taken to fix a 2/3 shift problem like yours during tuning. I ended up getting HPTuners, and after reading some, found my problem immediately. It took a simple correction in the commanded mph table at WOT, and my 2/3 missed shifting has vanished.
Thanks for sharing your experience, sounds like whet I'm going through. The car hasn't had a road tune as long as I've owned the car and needs one. The rear end clank seemed to get worse after my new intake, so I guess thats another indicator that it needs 0%throttle and light throttle tunning.
You said you know HP tuners, and found and fixed you're shift problem That is what I want to get into once I get more fimiliar with what is involved. I'm sick of paying for stuff to be tuned, and tuned half assed at that. The shift mph is something I've considered because that would throw it wayy off, but I have no way of telling.
When I first got the car the speedometer was off, so I took it in to get it fixed and I was thinking: Could he have had the wrong gear setting in (making speedo read off) and fixed that to fix the speed, but not changed anything else as far as shift speed, rpm, throttle%?
Thanks Again
10-20-2011, 11:33 AM
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Yeah, yours does seem to be a general tuning issue that has to do with fueling. Your trans tune may be very close to being good. I would double check stuff like tire size and gear ratio, just to be on the safe side. I think if you got HPTuners, we could get you lined out pretty quickly on the trans stuff. Actually, trans tuning is a great way to get started. Its an easy way to narrow down the program to a few specific tables, then get you familiar with the logging/reading/changing/flashing part of the program. Taking on something like HPTuners from scratch is quite overwhelming, so keeping it simple is a good thing. Thats how I started when I got it. One of these days I'm gonna learn the fuel stuff 
10-20-2011, 12:00 PM
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Ok, cool. Right now the car has an EFI Live SD tune. I'm going to look up the Hp tuners and see what its all about and how much $ it runs for. Are their any pros/cons to Hp tuners vs Efi live? Or do they pretty much get the job done the same?
And thanks alot for sharing your perspective on the tunning thing and starting with trans tunning because it definitely seems overwhelming with it all the tables/paramaters and everything else involved that I dont even have a clue about yet lol
And thanks alot for sharing your perspective on the tunning thing and starting with trans tunning because it definitely seems overwhelming with it all the tables/paramaters and everything else involved that I dont even have a clue about yet lol
10-20-2011, 12:56 PM
#17
Thats great info. The devil is in the details with these trannies and the tuning. 9 out of 10 Tuners will not street tune the tranny. Because they have never taken time to learn how the tranny operates and most importantly how it is affected by the engine tune they inadvertantly create tranny problems. This forum is full of tuning issues that go back some ten years. It isn't a mystery, it isn't easy but if someone takes the time to get it right the 60e is actually a bad *** transmission if it's built properly. And by that I mean built by someone who knows it inside and out and has pushed the envelope by imventing components and improving existing components.
I think you're on the right track now. At least you have a better understanding of what needs to happen in order to improve the driving characteristics of your car.
Read all the appropriate stickies regarding tuning the trannys and take it from there. We'll help ya.
g
I think you're on the right track now. At least you have a better understanding of what needs to happen in order to improve the driving characteristics of your car.
Read all the appropriate stickies regarding tuning the trannys and take it from there. We'll help ya.
g
10-20-2011, 04:31 PM
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First thing I would suggest is to register on HPTuners forum. Lots of info there to get you started. I never really considered EFI simply because everyone around here uses HPT. Coolaid made a fantastic write up on trans tuning. Its on HPT forum and here. Great place to start your reading.
10-20-2011, 10:38 PM
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You need to put a pressure gauge on the line tap on the side of the case... and then watch the gauge as you bring the RPM up.
Performabuilt said above you might be running the pan dry and cavitating the pump at WOT... where is your fluid level at...? Try an experiment: overfill by 1 quart and see if the slipping at WOT still happens (what does the pressure gauge show).
How are you detecting the slipping...?
How do you know that it's not a problem in the stall converter...? The dip in the dyno graph could also be caused by other things (e.g. valvetrain, pulley/damper).
[ Is the fluid turning color...? ]
Something tells me you should check the fluid flow coming out of the cooler return line (should get at least 2 quarts in 20-30 seconds).
Performabuilt said above you might be running the pan dry and cavitating the pump at WOT... where is your fluid level at...? Try an experiment: overfill by 1 quart and see if the slipping at WOT still happens (what does the pressure gauge show).
How are you detecting the slipping...?
How do you know that it's not a problem in the stall converter...? The dip in the dyno graph could also be caused by other things (e.g. valvetrain, pulley/damper).
[ Is the fluid turning color...? ]
Something tells me you should check the fluid flow coming out of the cooler return line (should get at least 2 quarts in 20-30 seconds).
10-21-2011, 08:28 PM
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First thing I would suggest is to register on HPTuners forum. Lots of info there to get you started. I never really considered EFI simply because everyone around here uses HPT. Coolaid made a fantastic write up on trans tuning. Its on HPT forum and here. Great place to start your reading.
You need to put a pressure gauge on the line tap on the side of the case... and then watch the gauge as you bring the RPM up.
Performabuilt said above you might be running the pan dry and cavitating the pump at WOT... where is your fluid level at...? Try an experiment: overfill by 1 quart and see if the slipping at WOT still happens (what does the pressure gauge show).
How are you detecting the slipping...?
How do you know that it's not a problem in the stall converter...? The dip in the dyno graph could also be caused by other things (e.g. valvetrain, pulley/damper).
[ Is the fluid turning color...? ]
Something tells me you should check the fluid flow coming out of the cooler return line (should get at least 2 quarts in 20-30 seconds).
Performabuilt said above you might be running the pan dry and cavitating the pump at WOT... where is your fluid level at...? Try an experiment: overfill by 1 quart and see if the slipping at WOT still happens (what does the pressure gauge show).
How are you detecting the slipping...?
How do you know that it's not a problem in the stall converter...? The dip in the dyno graph could also be caused by other things (e.g. valvetrain, pulley/damper).
[ Is the fluid turning color...? ]
Something tells me you should check the fluid flow coming out of the cooler return line (should get at least 2 quarts in 20-30 seconds).
As far as the cavitating the pan/pump I'm 99% sure thats not the case. It reads at the max full line on the dipstick. But I will try to overfill it and see if there is any difference.
I'm detecting what I am expecting to be slipping whenever I try to run the car through the 2-3 shift at wot
And I don't know that its not the stall converter, just trying to troubleshoot and find out what the problem is. I know the springs could use replaced soon, they are getting old and are starting to get valve float, but would that cause spikes or the line to just flatten out? What do you mean pulley and damper?
The fluid is almost as fresh comming out as it is when I put it in. I've done 2 changes on it since I've owned the car and each time the fluid is in good shape, not burnt or anything, and there isnt too much clutch material at all.
And checking the fluid return line is a good idea, I will also have to check that out