Trans fluid and lack of lockup

[THEFERMANATOR]

I went to the track Friday for the PRI race and for the heck of it I ran the BURB. First pass I babied it off the line and didn't go full throttle and ran a 9.11 in the 1/8th(I know not real fast, but respecteable for a 7000 pound family bus running a street tune), but on the subsequent passes I slowed down as it fell over in 4th because I wasn't getting lockup. I never had problems with not geting lockup with TRANSYND, but since switching to a DEX/MERC type fluid I no longer get lockup at WOT. I know a lockup box will take care of this problem, but the problem is I don't have the money for one, and my slippage everytime I check it is under the 600 RPM slip limit that many says is the limit in the TCM but still no lockup.

Since this problem started when I switched to the DEX/MERC fluid, I pulled up some spec sheets on different fluids and found some interesting info. What I found was that the CASTROL DEX/MERC fluid has a viscosity of 32 @40C and 7.2 @100C, QUATRASYN has a viscosity of 36.5 @40C and 7.25 @100C(very close to that of DEX/MERC fluid, and AMSOIL TORQUE DRIVE), but TRANSYND has ratings of 53.9 @40C and 9.75 @100C. I switched to DEX/MERC fluid and stayed with it as it gives a MUCH better shift feel to it VS the TRANSYND(much more positive shifts), but it has made my converter feel looser up top under power.

What I'm wondering is if there is anything to the viscosity difference and the lack of lockup many experience under bigger power? And if so, what fluid would be a good compromise between the major fluids out there? Or is there maybe some additive out there you could go to to maybe help raise the viscosity some to that of TRANSYND, but maintain the shift feel of DEX/MERC fluid?

http://www.castrol.com/liveassets/b...local_assets/downloads/p,q/pds_DomesticMV.pdf
http://www.docs.citgo.com/msds_pi/10148.pdf
http://www.castrol.com/liveassets/b...AGING/local_assets/downloads/t/TranSyndRD.pdf

 

[Mike L.]

Ferm
You are looking for love in all the wrong places. Fluid viscosity will add or subtract to clutch slippage but not control operation of any function. It cannot. You are fighting a control issue my friend. TCM.

 

[THEFERMANATOR]

Ferm
You are looking for love in all the wrong places. Fluid viscosity will add or subtract to clutch slippage but not control operation of any function. It cannot. You are fighting a control issue my friend. TCM.

That's what I figured, just not what I want to hear. It just makes no sense that I'm not getting lockup when my slippage is under the 600RPM window. When my trans was at 140 on the first 2 passes I got lockup in 4th and it pulled like a mule on the big end(2nd pass spun all 4 till about the 200 foot mark on a boosted launch), but the 3rd and 4th passes it got up over 170 and no more lockup. Was thinking maybe the thicker fluid may help with the fluid coupling a bit to help get me lockup. I know with the TRANSYND in it I still got lockup even on a PPE level 6 tune I tried out, but since the fluid switch no more lockup until mid way through 4th. To bad a lockup box costs so much, then again it's a family wagon not a drag truck.

 

[leehype]

I have read somewhere that there are conditions that must exist for the TC to lock up, one of which was the amount of "slip" in the TC. I'm just guessing here, but after reading your post, I think I am reading that you are thinking the same thing.

So if the TC is slipping more as the trans temps increase, then trouble shooting shouldn't be hard, get the trans cool, run a pass, run it again when it is hot. At least you can figure out if this is the problem or if there is a controller issue as mentioned.

And if this trully is the case, would increasing the trans cooling be within reason?

 

[Mike L.]

I have read somewhere that there are conditions that must exist for the TC to lock up, one of which was the amount of "slip" in the TC. I'm just guessing here, but after reading your post, I think I am reading that you are thinking the same thing.

So if the TC is slipping more as the trans temps increase, then trouble shooting shouldn't be hard, get the trans cool, run a pass, run it again when it is hot. At least you can figure out if this is the problem or if there is a controller issue as mentioned.

And if this trully is the case, would increasing the trans cooling be within reason?

Do you have any idea what converter slip means? Converter clutch slip is a totaly different thing. Converter slip is a hydraulic and mechanical action. It is not a slip; it is only called a slip for lack of better words. temps have nothing to do with it. Wheel spin does as far as the TCM is concerned.

 

[leehype]

Do you have any idea what converter slip means? Converter clutch slip is a totaly different thing. Converter slip is a hydraulic and mechanical action. It is not a slip; it is only called a slip for lack of better words. temps have nothing to do with it. Wheel spin does as far as the TCM is concerned.

Guess you didn't understand what I was saying, nor do I think you understand how a lockup converter works. The converter is not "slipping the clutch" right off the bat. It is a turbine, the trans fluid is the working fluid. At a cirtain point, when several conditions are met (these change from trans to trans) the converter will lock up. If the clutch was attempting to lock up, but still slipping, it would be burnt out in very little time. Think about a manual trans, if you slip that clutch nonstop, what will happen to it?

Ok, so now there is the TQ converter, when unlocked the trans input is spinning at a different speed then the flywheel. When it locks up, the input and flywheel now spin at the same speed (I believe this is what you are refering to.) The problem is, if the flywheel and trans input speeds are too far off from each other, the converter will not lock up to prevent excessive shock load through out the trans.

The way the OP stated the problem, it sounds like the converter is slipping too much for the lockup to engauge.

Not trying to "school" you or sound like a know it all, but I really think you miss read the issue...

 

[THEFERMANATOR]

Mike understands my issue as it plagues many of us who start upping the power as teh TCM has a hard limit in it that will not allow lockup if it sees X amount of slippage through the converter. It is really annoying though as I ran a 9.11 babying it, but I slowed down to a 9.20 when I got on it because I didn't get lockup on the 3rd and 4th passes. Would be nice if EFILIVE would find the tables for this issue, but with 2 different companies making lockup controllers it isn't high on there list of things to do. And I just don't have the coin to spend right now on a lockup controller for a family bus.

 

[leehype]

Mike understands my issue as it plagues many of us who start upping the power as teh TCM has a hard limit in it that will not allow lockup if it sees X amount of slippage through the converter. It is really annoying though as I ran a 9.11 babying it, but I slowed down to a 9.20 when I got on it because I didn't get lockup on the 3rd and 4th passes. Would be nice if EFILIVE would find the tables for this issue, but with 2 different companies making lockup controllers it isn't high on there list of things to do. And I just don't have the coin to spend right now on a lockup controller for a family bus.

I'm not trying to get into a fight on the internet, just that I read your problem one way, and I think he read it a different way. I also started off with a troubleshooting suggestion, and he attacked my experience.

Upping the power would cause more slip, and bypass the lockup, I get that, and I just said that. Your first question was to start mixing fluids to increase the viscosity of the trans fluid to reduce the TQ slip (at least this is what or how I read and interprited your first post.) Once again, I believe I read that when the fluid was cooler (IE, thicker) your trans was locking up as it should, but when hot (IE, thinner, and likely slipping more) it was not locking up. My first recomendation was to check to see if you could duplicate this issue, and over come it with out mixing fluids, or taking anything apart. If nothing else, if this would work, you could wait for your trans to cool after every run to keep your times good.

And again, I wasn't trying to start a pissing match. I haven't even put 3k miles on mine in the few months I've owned it, and I'm simple reading through as many threads to learn as much as possible. I don't have a great deal of experience on this engine or trans, so I am stuck using all the rest of my experience to diagnose issues. If this is unacceptable, then I will leave.

 

[Slammed2007Lbz]

Guess you didn't understand what I was saying, nor do I think you understand how a lockup converter works. The converter is not "slipping the clutch" right off the bat. It is a turbine, the trans fluid is the working fluid. At a cirtain point, when several conditions are met (these change from trans to trans) the converter will lock up. If the clutch was attempting to lock up, but still slipping, it would be burnt out in very little time. Think about a manual trans, if you slip that clutch nonstop, what will happen to it?

Ok, so now there is the TQ converter, when unlocked the trans input is spinning at a different speed then the flywheel. When it locks up, the input and flywheel now spin at the same speed (I believe this is what you are refering to.) The problem is, if the flywheel and trans input speeds are too far off from each other, the converter will not lock up to prevent excessive shock load through out the trans.

The way the OP stated the problem, it sounds like the converter is slipping too much for the lockup to engauge.

Not trying to "school" you or sound like a know it all, but I really think you miss read the issue...

WOW

 

[leehype]

WOW

Rodger that

To the OP:

Sorry for trying to help.

To Mike L:

Sorry for the misunderstanding.

 

[THEFERMANATOR]

Finally got to drive it after changing out my trans lines, swapped over to the EARLS 82510 cooler, hoot flush, and refilled with QUATRASYN. And this thing is like a whole nother truck. The torque converter is actually grabbing down low again, and lockup comes on in 2nd again under WOT.