TC lockup question
Thread Starter
Melting Slicks
Joined: Nov 2003
Posts: 3,011
Likes: 9
From: Dublin GA
TC lockup question
Odd question, but is there any way, while logging, to tell EXACTLY if the TC is locking up at cruise speed?
I was driving home today, when I noticed my "instant mpg" was lower than usual at 60mph (16-18 instead of the 23-25 normal) The rpm seemed to be a little higher (2000 instead of 1800-1900 from memory) and my trans temps were climbing to the 220 range normally in the 195-200 range although it WAS hot)
I rechecked my lock up values and they seemed correct, but just wondered if there was somthing else to check. Have not had an issue before.
I was driving home today, when I noticed my "instant mpg" was lower than usual at 60mph (16-18 instead of the 23-25 normal) The rpm seemed to be a little higher (2000 instead of 1800-1900 from memory) and my trans temps were climbing to the 220 range normally in the 195-200 range although it WAS hot)
I rechecked my lock up values and they seemed correct, but just wondered if there was somthing else to check. Have not had an issue before.
Le Mans Master
Joined: Aug 2005
Posts: 5,375
Likes: 328
From: CA.
St. Jude Donor '13-'14-'15
Someimes it's hard to tell if tour TCC is locking up-especially if your 3-4 shist speed MPH is higher than your TCC lock up speed at the same throttle position--The ECM will try to shift them both at the same time
If your RPM's though indicate that the TCC is NOT locked--you can do some tuning that will make it shift firmer--
Go to the TCC section in your trans files--then go to the "PWM" tables
Set the entire minimum table to 95 % and the entire maximum table to 98%---this will make it shift firmer
I suspect that the heat and normal trans wear may make it lock up lazily---
PS : GM makes the TCC lock up way to early--I think the stock setting is like only 38 MPH down low on the TPS---This makes the car lug or chung chung chug when the converter is trying to lock--as the line pressure is just too low-
I set all cars and trucks to lock up (depending on gear ratio and tire size I may vary it slightly)) at a minimum of 50 MPH up to around 35 TPS at have it release at 40 MPH up to the same TPS---
I also delete the entire 3rd gear lock/unlock settings
Basically I beleive it's best to only have it lock up on the freeway for cruising in 4th gear--elimiates the constant locking/unlocking during city driving which creates more heat and wear--
If your RPM's though indicate that the TCC is NOT locked--you can do some tuning that will make it shift firmer--
Go to the TCC section in your trans files--then go to the "PWM" tables
Set the entire minimum table to 95 % and the entire maximum table to 98%---this will make it shift firmer
I suspect that the heat and normal trans wear may make it lock up lazily---
PS : GM makes the TCC lock up way to early--I think the stock setting is like only 38 MPH down low on the TPS---This makes the car lug or chung chung chug when the converter is trying to lock--as the line pressure is just too low-
I set all cars and trucks to lock up (depending on gear ratio and tire size I may vary it slightly)) at a minimum of 50 MPH up to around 35 TPS at have it release at 40 MPH up to the same TPS---
I also delete the entire 3rd gear lock/unlock settings
Basically I beleive it's best to only have it lock up on the freeway for cruising in 4th gear--elimiates the constant locking/unlocking during city driving which creates more heat and wear--
Thread Starter
Melting Slicks
Joined: Nov 2003
Posts: 3,011
Likes: 9
From: Dublin GA
Thanks TB
I changed my TCC settings. I agree on the 3rd gear lock up, but didn't know what guys were doing. What relationship do I need to maintain between the TCC lockup and 3-4 shift?
I've got a RPM V trans that I havebeen trying to get dialed in as far as pressure etc goes. I had asked one of the local venders what he would charge to take a look and he said "nothing", but never got back
Chris
Not sure what you mean in the last portion of the post. I have a 3500 stall
Thanks for the help guys
I changed my TCC settings. I agree on the 3rd gear lock up, but didn't know what guys were doing. What relationship do I need to maintain between the TCC lockup and 3-4 shift?
I've got a RPM V trans that I havebeen trying to get dialed in as far as pressure etc goes. I had asked one of the local venders what he would charge to take a look and he said "nothing", but never got back
Not sure what you mean in the last portion of the post. I have a 3500 stall
Thanks for the help guys
Le Mans Master
Joined: Aug 2005
Posts: 5,375
Likes: 328
From: CA.
St. Jude Donor '13-'14-'15
Ok if yo have a 3500 stall---do as I suggested and set the PWM min table to 95 and the PWM table max to 98 --It is found in the TCC section
Also very important--a stall creates false misfires---A misfire whether real or false will UNLOCK the TCC--- To correct this you must go to your "misfire tables" in the engine diagnostics" section and MAX OUT all of them !!!Some people just add like 25% to all of them--I like maxing them all out----
Your constant locking/unlocking of the TCC may be a result of this alone----
Also very important--a stall creates false misfires---A misfire whether real or false will UNLOCK the TCC--- To correct this you must go to your "misfire tables" in the engine diagnostics" section and MAX OUT all of them !!!Some people just add like 25% to all of them--I like maxing them all out----
Your constant locking/unlocking of the TCC may be a result of this alone----
