4L60E Commomn Problems & Solutions
#1
11-28-2009, 09:36 PM
4L60E Commomn Problems & Solutions
http://www.gmtruckhq.com/?q=node/93
Includes the dreaded failure to upshft @ WOT
Includes the dreaded failure to upshft @ WOT
#2
01-10-2012, 04:52 PM
ok so heres some stuff i figured out
To put a ’95 4L60E into a ’94 car: No mechanical mods required. The TCC valve mod must be performed to remove the PWM function. The trans will operate normally without the mod but TCC lockup will not work, so highway and cruising gas mileage will suffer and more heat will be produced in the transmission.
To put a ’96 4L60E into a ’94 car: The ’94 tailshaft housing and VSS must be installed on the ’96 4L60E before the trans can be bolted into the car. The TCC mod must be performed. The trans will operate normally without the TCC mod but TCC lockup will not work, so highway and cruising gas mileage will suffer and more heat will be produced in the transmission.
TCC Mod: Leave the PWM solenoid unplugged but installed. On the valve directly to the right of the PWM solenoid – push that valve all the way towards the outside of the valvebody, and stake it into place. That’ll lock keep the valve acted on by the PWM in the full-open position and it’ll function like a '94 style lockup. No PCM reprogramming required.
Putting a '95-96 trans in a '94?
This is the 4L60E TCC modification first done back in the mid-late 1990s which consists of staking the TCC regulated apply valve in the full-open position, eliminating the PWM function. The mod is reversible if you stake carefully.
Why? In 1995, GM added a second control solenoid to the 4L60E Torque Converter Clutch (TCC) to allow them to better control the way the torque converter clutch lockup felt. The original on-off solenoid still enables lockup, and the new solenoid (the "apply" solenoid) controls a slide valve in the valvebody via "pulse-width modulation" (PWM)- what that means is that the solenoid is turned on and off rapidly but the time "on" and the time "off" are varied like a fuel injector (like "duty cycle") to control the amount of fluid released by the solenoid, and this controls lockup. Smooth shifts are easier on the drivetrain with little loss in performance.
That said, the valvebody valve acted upon by the PWM solenoid tended to wear the bore and cause problems. GM techs figured out that if the valve was staked in the full-open position, the code would go away. The downside of that fix was that now the torque converter becomes pressurized with transmission line pressure, which can go as high as 250psi at times. In a properly functioning 4L60E, lockup pressure should really be around 100psi or so. Given the size of the torque converter, this much higher pressure can physically distort the case of the converter and cause other problems.
Sonnax developed a repair kit for this, which includes improved valves and a special sleeve which not only eliminates future bore wear, but improves the valve structure themselves. It is P/N 77754 (pay attention as there are suffixes for the different aspects of this fix)).
One thing to note is that you will have to remove the valvebody and also purchase a reamer tool which is not cheap (~$85). You can always sell this tool on ebay once your done, or charge four friends $20 each and fix theirs while you're at it, then you're back to zero.
Finally, if you're putting a '95 or '96 transmission in a '94 vehicle, the '94 electrical system doesn't have provisions to control the PWM solenoid and so you will have no lockup at all if you leave it as-is.
NOTE: If you have installed a TransGo HD2 kit into this transmission, you don't need to do this mod. The Transgo kit converts the setup to an on-off setup rather than a modulated setup. You can also make your own spring or spacer that locks the valve at full open, but staking is easier and quicker.
and finally the trans go HD2 shift kit
TransGo Performance 4L60E-HD2 - TransGo Performance Shift Kits - Overview - SummitRacing.com
if you guys think this is all cool i got a 95 trans lined up 150$ guy bought it for his 01 TA and realized it wont work says its got 120k on it
To put a ’95 4L60E into a ’94 car: No mechanical mods required. The TCC valve mod must be performed to remove the PWM function. The trans will operate normally without the mod but TCC lockup will not work, so highway and cruising gas mileage will suffer and more heat will be produced in the transmission.
To put a ’96 4L60E into a ’94 car: The ’94 tailshaft housing and VSS must be installed on the ’96 4L60E before the trans can be bolted into the car. The TCC mod must be performed. The trans will operate normally without the TCC mod but TCC lockup will not work, so highway and cruising gas mileage will suffer and more heat will be produced in the transmission.
TCC Mod: Leave the PWM solenoid unplugged but installed. On the valve directly to the right of the PWM solenoid – push that valve all the way towards the outside of the valvebody, and stake it into place. That’ll lock keep the valve acted on by the PWM in the full-open position and it’ll function like a '94 style lockup. No PCM reprogramming required.
Putting a '95-96 trans in a '94?
This is the 4L60E TCC modification first done back in the mid-late 1990s which consists of staking the TCC regulated apply valve in the full-open position, eliminating the PWM function. The mod is reversible if you stake carefully.
Why? In 1995, GM added a second control solenoid to the 4L60E Torque Converter Clutch (TCC) to allow them to better control the way the torque converter clutch lockup felt. The original on-off solenoid still enables lockup, and the new solenoid (the "apply" solenoid) controls a slide valve in the valvebody via "pulse-width modulation" (PWM)- what that means is that the solenoid is turned on and off rapidly but the time "on" and the time "off" are varied like a fuel injector (like "duty cycle") to control the amount of fluid released by the solenoid, and this controls lockup. Smooth shifts are easier on the drivetrain with little loss in performance.
That said, the valvebody valve acted upon by the PWM solenoid tended to wear the bore and cause problems. GM techs figured out that if the valve was staked in the full-open position, the code would go away. The downside of that fix was that now the torque converter becomes pressurized with transmission line pressure, which can go as high as 250psi at times. In a properly functioning 4L60E, lockup pressure should really be around 100psi or so. Given the size of the torque converter, this much higher pressure can physically distort the case of the converter and cause other problems.
Sonnax developed a repair kit for this, which includes improved valves and a special sleeve which not only eliminates future bore wear, but improves the valve structure themselves. It is P/N 77754 (pay attention as there are suffixes for the different aspects of this fix)).
One thing to note is that you will have to remove the valvebody and also purchase a reamer tool which is not cheap (~$85). You can always sell this tool on ebay once your done, or charge four friends $20 each and fix theirs while you're at it, then you're back to zero.
Finally, if you're putting a '95 or '96 transmission in a '94 vehicle, the '94 electrical system doesn't have provisions to control the PWM solenoid and so you will have no lockup at all if you leave it as-is.
NOTE: If you have installed a TransGo HD2 kit into this transmission, you don't need to do this mod. The Transgo kit converts the setup to an on-off setup rather than a modulated setup. You can also make your own spring or spacer that locks the valve at full open, but staking is easier and quicker.
and finally the trans go HD2 shift kit
TransGo Performance 4L60E-HD2 - TransGo Performance Shift Kits - Overview - SummitRacing.com
if you guys think this is all cool i got a 95 trans lined up 150$ guy bought it for his 01 TA and realized it wont work says its got 120k on it
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