Hey All,

Long story short, swapped a LM7 into my 1990 K5 blazer, trans builder built me a 4L60E using the one piece case, everything works well except the TCC lockup, which isnt working at all and causes the trans to overheat.

Trans Shop and I talked today and he presented 2 options, need some input here:

Option 1: Use my HPTuners to change Minimum TCC Duty Cycle to 90%, max of 100%, bypassing PWM essentially.

Option 2: Build a 2 piece case 4L60E, order the adapter plate for my transfer case(np241c), install everything, and possibly have to fuss with my drivelines(trans+adapterplate moves the transfer case back about 3/4 of an inch apparently?)


Thoughts? No cost to me to do option 1, option 2 requires me to buy the adapter plate for a few hundred $$ and do the driveline work if needed, another fed hundred $$.

 

Option 3: Stand alone trans module $550 to $1100 bucks. On summit,, sure there are others..

 

Figure out why it's not locking up.
Brake switch,
Misfire,
Use your hptuners to lock the tcc and see if it locks.

 

Its not locking up because it has a non pwm tcc lockup setup. he says he cant put in the pwm solenoids in the one piece case, so software hack around the non pwm lockup.

I can see in HPTuners lockup being commanded and not happening, which means its a trans issue not a pcm/tune issue. I am monitoring every single parameter for lockup and they are all showing good to go, brake switch and tps etc all change status when they should.

 

Ok. It takes what 10 - 15 minutes to max out the duty cycle and upload the tune.
Or option 3: run a wire from the pcm directly to the lockup solenoid.

 

Couple different ways you can do this mechanically. 2 of them require you do drop the pan, but leave the valve body in place. BUT...these modifications are typically only done to make a pwm unit work with a computer setup that doesn't have any control over the pwm. or for someone that doesn't have the capability to tune the parameters.
If you have a trans with pwm (96+) then the computer should be controlling it...it's possible there is bore wear in either the reg apply valve or the tcc valve in the pump. but I digress...here's a couple ideas

1. pull the tcc pwm solenoid and remove the inboard (small) o ring. You can also grind a small slot between the nose (furthest most inboard) and the filter on the solenoid.
What this will do is send max afl fluid pressure to the Reg. Apply valve (essientially like having 100% duty cycle, all the time)

2. The reg apply valve is 2 piece. Remove the outboard valve, insert something in the bore to replace the spring that is there. A small piece of copper pipe works well. What you want to do is block the valve outboard. This will open the reg apply passage to full line...again like having 100% duty cycle all the time. Some shift kits do this with a tightly wound spacer spring.

3. do what others have suggested and just turn up the duty cycle in the tune. This may help, it may not. If you have issues in the AFL circuit...if you have leaks/bore wear...if you have a plugged tcc solenoid...etc etc etc then the tune won't actually give the results you want. If everything in the valve body is working properly, then the tune fix to very high duty cycles will be functionally the same as #1 or #2. I prefer the mechanical options (1 or 2) over the electrical options because I'm a mechanical guy.


If you're going to do the mechanical option...Do one or the other (I would do # 2 if it were me) not both.

If you have bore wear in either the TCC bore in the pump or reg apply in the VB then you're still likely to have issues regardless of which "fix" you use

 

He says it's a non PWM trans.

 

Didn't see that in the original post. Thanks.

Well...in that case...what is changing the pwm paramater in the tune going to do? A PWM 60e has 2 solenoids for lockup. One to control on/off (This is the same for all 60's...pwm or not. this is the solenoid that goes in the pump and is held to the case with 2 bolts). The other solenoid is the pwm one to control pressure to the lockup piston in the converter.

So...if it's non PWM...then maxing the pwm area in the tune isn't going to do anything. Adjusting the TCC apply tables will determine when it comes on/off but that's it.

I would find out what year the trans is and get a harness diagram for the trans. (easy to find if you know the year) and make sure the TCC enable wiring matches the wiring from your harness to the pcm. If the wiring changed throughout the years and the tcc enable pin is not in the same spot in the harness it will never lockup.