99 4l60e torque converter problem?

[Ghostyman25]

When in OD in my truck going steadily down the road it kinda chuggs. It acts like the torque converter is locking and unlocking. when i hit the brakes it unlocks and stays unlocked a few seconds like it should but when it locks back in it kinda kicks and goes to chugging again. It only does this in OD..had the code read and several catalytic ones came up(expected because the truck has no cats) and then the trans code 1870 came up. Says its experiencing excessive slippage and it could be either excessive fluid in it or an internal failure. The trans does have a bit too much fluid(not burnt) and the filter and fluid hasnt been changed in the last 31k miles i know for sure. Would changing the fluid and filter help any? How would i let a bit of fluid out(someone told me to undo the cooling lines)? Does this sound like it could just be the TC?

[transbuilderguy]

if the trans is overfilled it will churn the fluid and areate the fluid. in hydraulics air is not good because air is compressible if it has air in it it may be causing and apply issue. lower the fluid level to proper level and go from there see what happens if it persisits you may have a bad torque converter clutch or a bad bore in the valve.

[Ghostyman25]

Lets say letting fluid out doesnt help(will do that in the morning),Am i looking at the destruction of my trans or could it be as simple as just a new TC or reboring the valve?

[transbuilderguy]

look on my facebook link at my sig and go to my pic look in my "what I do album" there are three pics on how to mod the VB to not have to take the VB off and its a free mod it will block PWM lockup and make it on or off

[Ghostyman25]

look on my facebook link at my sig and go to my pic look in my "what I do album" there are three pics on how to mod the VB to not have to take the VB off and its a free mod it will block PWM lockup and make it on or off

I was with you up until PWM lockup. Whats PWM lockup and do i want it on or off?

[transbuilderguy]

the pwm in lamens terms causses a gradual apply of the lockup clutch for smooth operation however it does wear the clutch also the main thing is the bore wears out and begins to get innefficient due to fluid bypassing which is actually what takes the converter clutch out. By performing this mod you lock the valve down so it cant pulse therefore the clutch when commended to lockup is on and when commanded off its off no inbetween. the wear in the valve bore is what actually casues the locking and unlocking of the converter while cruising and eventually kills the converter clutch.

[Ghostyman25]

look on my facebook link at my sig and go to my pic look in my "what I do album" there are three pics on how to mod the VB to not have to take the VB off and its a free mod it will block PWM lockup and make it on or off

If you dont mind ill add you then delete you after i look at your pics because your profile is private.


the pwm in lamens terms causses a gradual apply of the lockup clutch for smooth operation however it does wear the clutch also the main thing is the bore wears out and begins to get innefficient due to fluid bypassing which is actually what takes the converter clutch out. By performing this mod you lock the valve down so it cant pulse therefore the clutch when commended to lockup is on and when commanded off its off no inbetween. the wear in the valve bore is what actually casues the locking and unlocking of the converter while cruising and eventually kills the converter clutch.

That sounds exactly like what ill have to do...about how long would this take?

[transbuilderguy]

drop the pan stake the valve put pan back on filler up as long as the converter clutch is still good this will work.

[Ghostyman25]

Would i have to drop the trans to change the TC clutch? Could i do it myself or would you recommend having it done by a professional.

[r90camarors]

I know this thread is a month old - but I think I may have the same issue with my 06. I thought it was exhaust harmonics at first, but the logs show the rpms jumping around 40-50 rpm when its happening. Mine tends to do it at low rpm (1200-1500) and a little load while locked in OD. I've been able to tune most of it out with EFI Live based on more realistic shift points, i.e. no more shifting into OD at 28mph....but 45mph is right at 1500 rpm locked.
I've found the PWM setting, and can pretty much turn it off, but is it too late? My main concern is that it happens well after the converter has locked.
I've also see the TCC pressure apply rate in the program, would there be anything to gain from that?

Ghostyman25 - you have to drop the trans and would be installing a different converter (clutch is internal). It depends on how mechanically incline you are - its not an overly complex job, but dropping a trans can be a pita without the right tools. You would save yourself a good amount of money if you can do it yourself.