$0D and 1998 4L60e

**Marcus** · 12-03-2021

Friends,
I had my '95 4L60e broken and decided to use a '98 instead. In principle it works, but only then did I discover that the '7427 calibration $0D does not support the 3-2 ON-OFF solenoid.
Is solenoid 3-2 mandatory?
Is there any way out of this?
I appreciate any help...
Thank you,
Marcus

**dave w** · 12-03-2021

Maybe a Stand-Alone Transmission Controller is an option?

https://www.usshift.com/usq2.shtml?g...kaAnB9EALw_wcB

Maybe two computers '7427 for the Engine and an OBD2 computer for the Transmission?

Link is for the 4L80E, but can also be configured for the 4L60E https://sites.google.com/site/sloppy...ans-controller

dave w

**lionelhutz** · 12-03-2021

All the 4L60e have a 3-2 solenoid. You posted on-off so I believe you mean pwm vs on-off. I have read maybe it changed from PWM to on-off and then I have also read that it just changed in design and resistance. I don't know which to believe, but it seems to have been PWM controlled. I've looked before and never found anything that actually verifies the operation for certain.

I am using a 96 transmission behind a 95 LT1 and it works fine. I can't say if the 3-2 solenoid actually works or just being connected is enough it doesn't set a code. From what I understand, the 3-2 solenoid only changes the firmness of the downshift. On = softer downshift and Off = firmer downshift. So, on the older ones if they are PWM then they will vary between on and off instead of only being one or the other. If the 95 PWM doesn't provide enough power to the solenoid to move the valve then I the 3-2 valve would just be off and the transmission would have the firmer downshift. Eventually, at low throttle the PWM level should get high enough that the solenoid will move the valve on. If it did that, it'd get the required on-off operation anyways.

Apparently, you can block the 3-2 valve and the transmission will still work right. Some builders and shift kits do that. So, it doesn't seem that important.

If you can find a table in the tune that gives the PWM output curve then set it to 100% for low throttle and 0% for high throttle. That would make it on-off control. I haven't found a table like that in the LT1 tune so I didn't do anything with it.

I do believe you can swap your 95 valve body into it if you needed to. The 3-2 solenoid is a difference resistance and the computer might not like it and throw a code. You can't just swap the solenoid, the VB is also different where the valve mounts.

Overall, you could try it first before changing anything and swap a 95 valve body onto it if it doesn't work. Of course, if you don't want to do the swap under the car then do the VB swap first and be safe.

**tayto** · 12-03-2021

blocking the 3-2 solenoid is now common practice in performance 4L60E transmissions. i know a few builders that do it on every 4L60e they do. https://ls1tech.com/forums/automatic...2-3-shift.html

you can just leave the solenoid plugged to avoid CEL. or if you have access to edit the calibration you can turn the code(s) off.

**Marcus** · 12-04-2021

Originally Posted by dave w

Maybe a Stand-Alone Transmission Controller is an option?

https://www.usshift.com/usq2.shtml?g...kaAnB9EALw_wcB

Maybe two computers '7427 for the Engine and an OBD2 computer for the Transmission?

Link is for the 4L80E, but can also be configured for the 4L60E https://sites.google.com/site/sloppy...ans-controller

dave w

Thanks Dave for your attention!
A second computer for the tranny seems expensive and a little complicated to me, but it's an idea to consider.

**Marcus** · 12-04-2021

Originally Posted by lionelhutz

All the 4L60e have a 3-2 solenoid. You posted on-off so I believe you mean pwm vs on-off. I have read maybe it changed from PWM to on-off and then I have also read that it just changed in design and resistance. I don't know which to believe, but it seems to have been PWM controlled. I've looked before and never found anything that actually verifies the operation for certain.

I am using a 96 transmission behind a 95 LT1 and it works fine. I can't say if the 3-2 solenoid actually works or just being connected is enough it doesn't set a code. From what I understand, the 3-2 solenoid only changes the firmness of the downshift. On = softer downshift and Off = firmer downshift. So, on the older ones if they are PWM then they will vary between on and off instead of only being one or the other. If the 95 PWM doesn't provide enough power to the solenoid to move the valve then I the 3-2 valve would just be off and the transmission would have the firmer downshift. Eventually, at low throttle the PWM level should get high enough that the solenoid will move the valve on. If it did that, it'd get the required on-off operation anyways.

Apparently, you can block the 3-2 valve and the transmission will still work right. Some builders and shift kits do that. So, it doesn't seem that important.

If you can find a table in the tune that gives the PWM output curve then set it to 100% for low throttle and 0% for high throttle. That would make it on-off control. I haven't found a table like that in the LT1 tune so I didn't do anything with it.

I do believe you can swap your 95 valve body into it if you needed to. The 3-2 solenoid is a difference resistance and the computer might not like it and throw a code. You can't just swap the solenoid, the VB is also different where the valve mounts.

Overall, you could try it first before changing anything and swap a 95 valve body onto it if it doesn't work. Of course, if you don't want to do the swap under the car then do the VB swap first and be safe.

Thanks for sharing your experience. I believe our case is very similar. I have access to TunerPro and have some editing experience. I'm going to work on table 3-2 and see the result. I also have a TECH2 and have checked the functioning of the '98 4L60e. Almost everything looks fine. When I test solenoid 3-2 I get the FAULT message in the feedback, but there is no error log in the PCM. So I'll leave it aside for now.

However, I have another problem that perhaps has nothing to do with the 3-2 solenoid, it just caught my attention. When I do a test drive everything works fine for a few miles. So the transmission hangs at 2 (limp mode? I don't know how to tell if the system is in limp mode). Everything works: reverse, neutral, park and low. Again, no codes. With Tech2 I turn off solenoid B but it goes back to being commanded by the PCM to ON. That's why I believe it's in Limp Mode. But I can't find the reason. I turn it off for a while, let it cool down, disconnect the battery and everything goes back to normal until the next test drive.

My next attempt will be to block error 66 regarding solenoid 3-2 failure in calibration, but I don't believe this will work.

**tayto** · 12-04-2021

what do you mean "hangs at 2"? meaning it doesn't shift to 3rd or 4th gear? Or it revs up but doesn't go anywhere?

**Marcus** · 12-04-2021

Originally Posted by tayto

what do you mean "hangs at 2"? meaning it doesn't shift to 3rd or 4th gear? Or it revs up but doesn't go anywhere?

The transmittion stuck in 2nd and no change for 1st, 3rd or 4th. Truck moves with obvious limitations.

**brian617** · 12-06-2021

"Limp mode" on a 4l60e is 3rd gear. The way you can tell is both shift solenoids will be OFF.

**tayto** · 12-06-2021

is it possible it's putting itself into limp mode because of the codes being set? either way i would get that in order especially if it's fine on initial drive and then goes into limp mode.

**Marcus** · 12-09-2021

Friends,
Today I did a new 'test drive' which lasted about 30 minutes.
First I warmed up the engine.
I used the TunerPro log recorder.

Initial Conditions:
Engine Temperature: 176 degrees
Transmission temperature: 86 degrees
Oil pressure: 65 lbs (idle).

During the first 12.5 minutes, I did a mixed course and everything went perfectly. All gears shifted correctly including TCC. Oil pressure varying by load.
Engine temperature: 190 degrees
Transmission temperature: 155 degrees
Oil pressure: 65 lbs (idle).

Then, from the 13th minute onwards, the gear 'locked' in 2nd and the oil pressure practically fixed at 110 pounds. I drove home for a few more minutes.

Final conditions: Engine temperature: 183 degrees
Transmission temperature: 220 degrees
Oil pressure: 110 lbs.

I turned off the engine. After every 5 minutes I turned it on and wrote down the pressure. After approximately an hour the pressure returned to normal (idle, 65 lbs).

My impression is that the ECM is forcing this situation, I just can't figure out the cause. Clearly it's turning on solenoid B and putting a current of 0.7 amp into the Force Motor.

Any idea?

**brian617** · 12-09-2021

Trans over temp? Hot mode?

**Marcus** · 12-10-2021

Originally Posted by brian617

Trans over temp? Hot mode?

no...

**Marcus** · 12-10-2021

Originally Posted by brian617

Trans over temp? Hot mode?

Does not seem to me. At the time of failure the temperature is normal. Even at the end of the route it is on the limit, but without codes. I'm also suspicious of the temperature, that's why I kept an eye on it.