4l60E interchange questions

[PWR SHFT]

Does a 4L60E from 95-97 work in a 94? My assumption is that 93's (4L60) was the only different tranny.

Thanks!

[GuillaumeC]

The info below is for the B-body, don't know if F-body is exactly the same.

To put a ’94 4L60E into a ’95 car: Direct bolt-in. The PCM must be reprogrammed with ’94 transmission base code to avoid setting a silent code (Check Engine Light (CEL) does not illuminate, but code stored in memory). Trans will operate normally without reprogramming, but the silent code (code 83) will inhibit TCC lockup. Three potential fixes (any one will work); 1. reprogram PCM so it doesn't look for the PWM solenoid, 2. Add the wire into the harness or swap the '95-96 harness into the car ALONG WITH the internal transmission harness with the PWM solenoid connected but leave the solenoid in the pan, not installed in the valvebody as a '95-96 setup would have, or 3. wire up a manual TCC lock switch by which you can lock and unlock the converter yourself.

To put a ’94 4L60E into a ’96 car: The ’96 tailshaft housing and VSS must be installed on the ’94 4L60E before the trans can be bolted into the car. The PCM must be reprogrammed with ’94 transmission base code to avoid setting a silent code (Check Engine Light (CEL) does not illuminate, but code stored in memory). Trans will operate normally without reprogramming, but the silent code (OBD2 equivalent of code 83) will inhibit TCC lockup. Three potential fixes (any one will work); 1. reprogram PCM so it doesn't look for the PWM solenoid, 2. swap the '95-96 harness into the car ALONG WITH the PWM solenoid connected but leave the solenoid in the pan, 3. wire up a manual TCC lock switch by which you can lock the converter.

To put a ’95 4L60E into a ’96 car: The ’96 tailshaft housing and VSS must be installed on the ’95 4L60E before the trans can be bolted into the car. Technically, the 3-2 downshift solenoid should be swapped also, but experience shows that it is not required.

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 ’95 car: The ’95 tailshaft housing and VSS must be installed on the ’96 4L60E before the trans can be bolted into the car. Technically, the 3-2 downshift solenoid should be swapped also, but experience shows that it is not required. No other modifications are necessary.

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 (method 1):
An additional wire must be run from the PCM connector D pin 6 to pin "U" on the trans harness for the TCC to work. Also, the PCM must be reprogrammed with ’95 transmission base code. In my opinion this is more work than its worth due to the amount of labor involved in properly routing an additional wire into the powertrain wiring harness.

TCC Mod (method 2):
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.

Source: http://www.impalassforum.com/vBulletin/showthread.php?t=232098

[CPT]

The sticky above explains the 4L60E year differences. A later 4L60E will physically bolt in, but it won't operate correctly. It will initially seem to operate, but the '93 (truck) and '94 4L60E uses a non PWM lock up strategy. This esentially means the torque converter uses an on/off lock up strategy. In '95, GM went to a Pulse Width Modulated apply, which means the converter clutch pulses during the lock up. To achieve this, the '95-up units have an extra solenoid, a different TCC control valve, different separator plate, and a different pump assembly. The '95-up wiring harness from the computer to the transmission also has an extra wire to operate the new PWM solenoid. Installing a later trans in a '94 will damage the lock up clutch in the converter. Once a 4L60E loses lock up, the 3-4 clutches will follow very shortly.

Frank

[CPT]

The info below is for the B-body, don't know if F-body is exactly the same.

To put a ’94 4L60E into a ’95 car: Direct bolt-in. The PCM must be reprogrammed with ’94 transmission base code to avoid setting a silent code (Check Engine Light (CEL) does not illuminate, but code stored in memory). Trans will operate normally without reprogramming, but the silent code (code 83) will inhibit TCC lockup. Three potential fixes (any one will work); 1. reprogram PCM so it doesn't look for the PWM solenoid, 2. Add the wire into the harness or swap the '95-96 harness into the car ALONG WITH the internal transmission harness with the PWM solenoid connected but leave the solenoid in the pan, not installed in the valvebody as a '95-96 setup would have, or 3. wire up a manual TCC lock switch by which you can lock and unlock the converter yourself.

To put a ’94 4L60E into a ’96 car: The ’96 tailshaft housing and VSS must be installed on the ’94 4L60E before the trans can be bolted into the car. The PCM must be reprogrammed with ’94 transmission base code to avoid setting a silent code (Check Engine Light (CEL) does not illuminate, but code stored in memory). Trans will operate normally without reprogramming, but the silent code (OBD2 equivalent of code 83) will inhibit TCC lockup. Three potential fixes (any one will work); 1. reprogram PCM so it doesn't look for the PWM solenoid, 2. swap the '95-96 harness into the car ALONG WITH the PWM solenoid connected but leave the solenoid in the pan, 3. wire up a manual TCC lock switch by which you can lock the converter.

To put a ’95 4L60E into a ’96 car: The ’96 tailshaft housing and VSS must be installed on the ’95 4L60E before the trans can be bolted into the car. Technically, the 3-2 downshift solenoid should be swapped also, but experience shows that it is not required.

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 ’95 car: The ’95 tailshaft housing and VSS must be installed on the ’96 4L60E before the trans can be bolted into the car. Technically, the 3-2 downshift solenoid should be swapped also, but experience shows that it is not required. No other modifications are necessary.

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 (method 1):
An additional wire must be run from the PCM connector D pin 6 to pin "U" on the trans harness for the TCC to work. Also, the PCM must be reprogrammed with ’95 transmission base code. In my opinion this is more work than its worth due to the amount of labor involved in properly routing an additional wire into the powertrain wiring harness.

TCC Mod (method 2):
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.

Source: http://www.impalassforum.com/vBulletin/showthread.php?t=232098

Doing the modifications from that thread will cause transmission failure. We see people trying these mods all the time. You can't run a 4L60E without lock up. The sprag in the converter will continue to slip. The slipping will overheat the fluid. The first point of failure from generating too much heat is the 3-4 clutch.

Frank

[GuillaumeC]

Doing the modifications from that thread will cause transmission failure. We see people trying these mods all the time. You can't run a 4L60E without lock up. The sprag in the converter will continue to slip. The slipping will overheat the fluid. The first point of failure from generating too much heat is the 3-4 clutch.

Frank


The two TCC mods are used to get the TCC to work without the PWM function, not to get them to run without lock up.

[CPT]

...And interchanging the '95 unit with a '96 unit will throw a code. Changing the solenoid is a "band Aid on a bullet wound". It causes a 3-2 downshift run away. The ONLY way to swap years is to also swap computers/programs. The original post asked about using a '95-newer in a '94 vehicle. Not only would he have to swap computers, but he would have to swap harnesses. It all depends... If someone wants a "hack", half assed "fix" that will destroy their transmission, they can try one of the above methods. If he wants to do the job correctly, he should install the correct year transmission in the car. The disturbing part is, I see other transmission shops mixing incompatible years... All with the same results. When I build a core for a customer, I make certain I give them the same year transmission that came out. If swapping years were that easy, I could save myself alot of time searching for cores. The point is, it's not the correct way to do it, and it will cause problems in the long run...

Frank

[GuillaumeC]

Are the casing different with the 94-95-96? or is it just the comonents inside that change?

Thanks for the info, this is good to know!

[CPT]

Are the casing different with the 94-95-96? or is it just the comonents inside that change?

Thanks for the info, this is good to know!

The caes themselves are all interchangeable, until you get to the 'later bolt on bell style. The only differences being the 3.1 V-6 bell. Some cases have different mounting provisions for neutral safety switches, and floor shift brackets. There are also different converter dust covers. Other than that, the cases are identical inside. The '93 (truck) and '94 4L60E uses a non PWM pump. All '95-up pumps have the letters PWM cast on them. The earlier one's don't. Here's where it gets tricky...LOL Eventhough the early units were non PWM, they shared the same valve body casting with the '95. The difference being the TCC Control valve line up. Eventhough the early units didn't use a PWM solenoid, the valve bodies were cast with the hole for them. This means you can swap these valve bodies just by swapping the TCC control valve and adding or deleting the solenoid. The vavlve body casting itself changed in '96. The 3-2 downshift valve changed to a 1 piece design instead of the previous 2 piece design. Early 3-2 valves were held in by a retaining clip. The 1 piece valves were only held in by the 3-2 solenoid itself. When you take the 3-2 solenoid out of a '96-up valve body, the valve will fall out. '96 and '97 valve body castings are the same. '95,'96, and '97 pumps are interchangeable. A '93 (truck) and '94 separator plate doesn't have the feed holes for the PWM solenoid. A '95 plate has 2 holes over the 3-2 valve. '96-up plates have only 1.

Frank

[GuillaumeC]

Great info, thanks!

[PWR SHFT]

The caes themselves are all interchangeable, until you get to the 'later bolt on bell style. The only differences being the 3.1 V-6 bell. Some cases have different mounting provisions for neutral safety switches, and floor shift brackets. There are also different converter dust covers. Other than that, the cases are identical inside. The '93 (truck) and '94 4L60E uses a non PWM pump. All '95-up pumps have the letters PWM cast on them. The earlier one's don't. Here's where it gets tricky...LOL Eventhough the early units were non PWM, they shared the same valve body casting with the '95. The difference being the TCC Control valve line up. Eventhough the early units didn't use a PWM solenoid, the valve bodies were cast with the hole for them. This means you can swap these valve bodies just by swapping the TCC control valve and adding or deleting the solenoid. The vavlve body casting itself changed in '96. The 3-2 downshift valve changed to a 1 piece design instead of the previous 2 piece design. Early 3-2 valves were held in by a retaining clip. The 1 piece valves were only held in by the 3-2 solenoid itself. When you take the 3-2 solenoid out of a '96-up valve body, the valve will fall out. '96 and '97 valve body castings are the same. '95,'96, and '97 pumps are interchangeable. A '93 (truck) and '94 separator plate doesn't have the feed holes for the PWM solenoid. A '95 plate has 2 holes over the 3-2 valve. '96-up plates have only 1.

Frank

Thanks for the in-depth info as always, Frank.

A side question, you stated that all housings were the same with the exception of the 3.1L V6. Does that mean the 3.8L V6 interchanges? If so, does that go for the 3.8L V6 Torque Converters too?

[CPT]

Thanks for the in-depth info as always, Frank.

A side question, you stated that all housings were the same with the exception of the 3.1L V6. Does that mean the 3.8L V6 interchanges? If so, does that go for the 3.8L V6 Torque Converters too?

Chris, Sorry I didn't include the 3.8. The 3.8 in the F-Body used the same bellhousing as the 2.8/3.1.

Frank

[PWR SHFT]

What about the converters?

[NoMoneyZ]

Might explain why my 94 trans in my 95 car doesn't have lock up. Been running it for many years hard and no issues besides horrible mileage and ridiculously hard 1-2 shifts.

[JCzNova]

95 was pulse width modulation as well. Went from my 95 to a 94 trans in mine.

[CPT]

What about the converters?

Different converters.

Frank

[Tinbender59]

Hay Frank; Will a 1999 4L60E go into my 1997 pickup? I am salvaging the wifes Burb, rebuilding the trans and using the auto 4X4 TC as well in my truck, ( at least that is the plan) I do have a 411 ECU out of a 2002 running the show

[CPT]

Hay Frank; Will a 1999 4L60E go into my 1997 pickup? I am salvaging the wifes Burb, rebuilding the trans and using the auto 4X4 TC as well in my truck, ( at least that is the plan) I do have a 411 ECU out of a 2002 running the show
As long as it's not a LATE 1999 unit. '99 was a transfer year for trucks. Some 4L60Es were LS based. As long as the '99 came from a 5.7, you'll be OK. I'm pretty sure the Suburbans didn't swap to the LS style engine in mid '99, like the trucks did. The '02 computer will operate the '99 trans just fine.

Frank

[Tinbender59]

As long as it's not a LATE 1999 unit. '99 was a transfer year for trucks. Some 4L60Es were LS based. As long as the '99 came from a 5.7, you'll be OK. I'm pretty sure the Suburbans didn't swap to the LS style engine in mid '99, like the trucks did. The '02 computer will operate the '99 trans just fine.

Frank

It is a 5.7 Burb, also Frank I have a nagging question in the back of my mind, I'll throw it at you for your take on it. My truck is a 1997 LT1 powered with a TPI intake with Mega Torque and low end snap. I haul 1500lb round bails on the spear, and 10 at a time on the trailer occasionally. my son has a saw mill and we can get upwards of 6 tons of tree's on the trailer often and of corse the occasional car to haul. we work the dog sh### out of her, should have been a 3/4 ton LOL. Oh I forgot I'M a LEAD FOOT, my high school nick name was Macer the Racer LOL. My dilemma is this; can a 4L60E be built to "put up with Me", or should I just pony up and do a 4L80E??? after reading your "how to launch a 4L60E" I'm really thinking I should just do the 80, also will the Auto 4X4 TC fit on an 80? I have a '95 diesel 2wd 80 under the bench.

[CPT]

It is a 5.7 Burb, also Frank I have a nagging question in the back of my mind, I'll throw it at you for your take on it. My truck is a 1997 LT1 powered with a TPI intake with Mega Torque and low end snap. I haul 1500lb round bails on the spear, and 10 at a time on the trailer occasionally. my son has a saw mill and we can get upwards of 6 tons of tree's on the trailer often and of corse the occasional car to haul. we work the dog sh### out of her, should have been a 3/4 ton LOL. Oh I forgot I'M a LEAD FOOT, my high school nick name was Macer the Racer LOL. My dilemma is this; can a 4L60E be built to "put up with Me", or should I just pony up and do a 4L80E??? after reading your "how to launch a 4L60E" I'm really thinking I should just do the 80, also will the Auto 4X4 TC fit on an 80? I have a '95 diesel 2wd 80 under the bench.

We have 700s and 4L60Es in pulling trucks. They can be built to take an amazing amount of abuse. I'm not a fan of the '80E in a race car, but they work great in trucks. Putting an '80E in it will need different driveshafts. The extension housing for a 60E and an 80E both use the same bolt pattern.

Frank

[Tinbender59]

i understand the race car issue, I'm just worried about the sprag load when pulling a 6 ton load into traffic.

[CPT]

i understand the race car issue, I'm just worried about the sprag load when pulling a 6 ton load into traffic.

We can build it so you can bring on the over run clutches in manual 3rd...Which is what you should be towing in anyway.

Frank

[Tinbender59]

We can build it so you can bring on the over run clutches in manual 3rd...Which is what you should be towing in anyway.

Frank

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