Converter not staying locked
Thread Starter
Joined: Mar 2011
Posts: 2,688
Likes: 19
From: Stratford, CT
Converter not staying locked Recently I noticed that my converter (yank ss3600) is not locking like it used to. Normally it'll lock at part throttle between 42-45 around town, and on the highway at any speed. When on the highway I can't feel the converter lock now, and when it does lock, it will unlock with any added throttle and Rpms will go up as if it were unlocked. All I can think of is fluid level because I dropped the pan when I had to change the trans dipstick grommet due to it being ripped and leaking, and have been checking and adding fluid since I fixed the grommet.
The thing I don't get is that it seems to lock like normal when the fluid is colder, but when it warms up, it isn't acting the same. What can cause these issues?
The thing I don't get is that it seems to lock like normal when the fluid is colder, but when it warms up, it isn't acting the same. What can cause these issues?
Moderator
Joined: Aug 2010
Posts: 7,323
Likes: 529
From: Ann Arbor, MI
Cold fluid is thicker and all pressures tend to be higher; it also leaks less past e.g. worn valves in the VB.
The TCC valve in the VB might be worn. Has it ever been replaced?
This is a very common problem and almost guaranteed by 150K miles.
It often leads to P1870 code.
A fault engine sensor, MAF or TBS, could also be the culprit causing the PCM to disable the TCC before it should. A good scanner, like HP Tuners, which can monitor the TCC enable signal might be needed to determine if it is a sensor/PCM problem or a trans problem.
The TCC valve in the VB might be worn. Has it ever been replaced?
This is a very common problem and almost guaranteed by 150K miles.
It often leads to P1870 code.
A fault engine sensor, MAF or TBS, could also be the culprit causing the PCM to disable the TCC before it should. A good scanner, like HP Tuners, which can monitor the TCC enable signal might be needed to determine if it is a sensor/PCM problem or a trans problem.
Thread Starter
Joined: Mar 2011
Posts: 2,688
Likes: 19
From: Stratford, CT
The trans is a built FLT with roughly 10k, so I haven't replaced anything inside of it. Would disconnecting the battery reset anything that might be wrong? I had a crank position code before it started having this problem, but I cleared it and it has not come back since.
Moderator
Joined: Aug 2010
Posts: 7,323
Likes: 529
From: Ann Arbor, MI
Given the newness of the trans and stating you had some code issues, I would now be more inclined to suspect a sensor/PCM/grounding issue. However, you really need the results of a scanner to be sure:
* A good trans shop will have such a scanner
* HP Tuners or EFI Live have such scanner and it doesn't cost anything to scan.
* Does anyone know if a rentable scanner from an auto store can show the TCC state?
* A good trans shop will have such a scanner
* HP Tuners or EFI Live have such scanner and it doesn't cost anything to scan.
* Does anyone know if a rentable scanner from an auto store can show the TCC state?
Thread Starter
Joined: Mar 2011
Posts: 2,688
Likes: 19
From: Stratford, CT
So I was able to drive the car tonight and noticed that the converter will lock at cruising speeds (45+), but only when I would take my foot off the throttle. Another thing that I forgot to mention in my OP was that the security light came on around the same time it started acting up. Could that have an impact on things?
I have a buddy local to me with hptuners so I'm hoping he can scan the car for any tcc issues.
I have a buddy local to me with hptuners so I'm hoping he can scan the car for any tcc issues.
On The Tree
Joined: Jun 2015
Posts: 113
Likes: 12
From: Hopewell Junction NY
So I was able to drive the car tonight and noticed that the converter will lock at cruising speeds (45+), but only when I would take my foot off the throttle. Another thing that I forgot to mention in my OP was that the security light came on around the same time it started acting up. Could that have an impact on things?
I have a buddy local to me with hptuners so I'm hoping he can scan the car for any tcc issues.
I have a buddy local to me with hptuners so I'm hoping he can scan the car for any tcc issues.
TECH Junkie
Joined: Dec 2012
Posts: 3,615
Likes: 1,327
From: Iowa
A. Start your own thread...bringing up 2 year old threads is usually not the best way to get an answer
B. Misfires will unlock the converter...This can also cause trans issues because having the converter unlocked can cause it to overheat
C. LOG IT. I'm not sure if you have or not...but use a scanner and check to see if TCC is being enabled or not...that way you can narrow it down to being either a PCM issue or a physical trans issue.
B. Misfires will unlock the converter...This can also cause trans issues because having the converter unlocked can cause it to overheat
C. LOG IT. I'm not sure if you have or not...but use a scanner and check to see if TCC is being enabled or not...that way you can narrow it down to being either a PCM issue or a physical trans issue.
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Verdad Gallardo Thread Starter
Joined: Mar 2011
Posts: 2,688
Likes: 19
From: Stratford, CT
I'm assuming i was a moron and didn't double check fluid levels after adding the bigger lines and cooler and this caused the issue since the new converter locks up fine.
TECH Junkie
Joined: May 2012
Posts: 3,050
Likes: 716
From: Poplarville, MS
Thread Starter
Joined: Mar 2011
Posts: 2,688
Likes: 19
From: Stratford, CT
Moral of the story boys and girls, check your fluid levels and don't assume anything, especially after adding a deeper trans pan, bigger lines, and a bigger cooler.