TCC slipping fixed
 

I have been having problems with the TCC slipping under light throttle, below 90k/hr. This has happened since I installed the 6.0L and a 11" trailblazer stall. For those that don't know, the TCC apply pressure is controled by a PWM valve that dumps the line pressure to give a softer clutch apply and release. TCC PWM duty cycle 100% = full pressure, I was only seeing 30-45% when it was slipping. I have been seaching for ways to correct the problem via tuning, it seems a lot of people have the same problem with non-stock TC's but no one had answers. Today I found this thread

http://www.hptuners.com/forum/YaBB.p...num=1087352688
So there is a base table and a offset that can be adjusted and a desired table and slip gain value that is not in HPtuners. The offset is subtracted from the base, then the desired table and slip gain are factored in, then the offset is added back to the result, The final should be close to the offset value. So the higher the offset value the higher the DC will be. But the offset value should be less then the base.

I set the TCC DC vs. line press vs. tran temp base table all to 100, and set the offset table all to 95. Now no more slipping, when the tcc locks, it locks instantly, and it feels like a 5th gear, TCC PWM duty cycle is now 95+% all the time.

HPtuners :hail:

how is that trail blazer converter and what kind of rpms is it stallign to?

Nice. Something else I can look into here... Thanks for the heads up.

After driving for 3 days now with an on or off TCC, I can say that the factory has the clutch doing a lot of slipping, I haven't compared fluid temps yet, but they have to be lower now.

With the higher stall, you can't hardly feel or hear the shifts 1-4 the rpm drops for a sec then back to what it was before the shift, but now when the TCC locks it feels like it went from first to OD. If I still had the 5.3L I would not like this setup, it didn't like to be locked at 1700rpm, but the 6.0L locked at 1100rpm? no problem.

6.0L torque :hail: :burn:

BTW Trailblazer TC stalls to 2700 RPM

Hey Black. How do you like that cam in the 6.0? Think im gonna snag me an 01 6.0 and want to try to use my current cam. Is it working well for you??

The best way to deal with the Pulse Width Modulation B/S is to kill it with hard parts.

Move the issolator valve to its fully-stroked position and replace the spring between it and the TCC signal valve with one too strong for it to move. The idea here is to prevent the issolator valve from moving at all.

Here's a picture of the spring I used:
http://james.jaguar.net/pics/pulsevalve.jpg

This worked great until the 3-4 clutches experienced an unrelated death.

The 212/218 cam works great in the 6.0L, tons of torque, right off idle. You could run a lot bigger cam with a 6.0L, but I like the big torque down low for towing.

I knew about shimming the PWM valve, but I wanted a quick fix, I plan on installing a transgo shift kit which fixes the valve permanently. Changing a few numbers on a computer is a lot easier then pulling the valve body down.

im TC retarted!!! but i guess what you are trying to say is that you wouldn't recoment the TC for a 5.3, because it didn't like to lock at 1700rpm?? <--- what does all this mean please go in more depth.

I was talking to an ex-member named Hitman and he was telling me there is a vac mod from transgo that is supposed to help with that problem I think.

Vac Mod Link

"TRANSGO® 46-MOD 4L60E Vacuum pressure control. This replaces the electronic pressure control solenoid for heavy duty and high performance use. Comes with complete, easy to follow instructions.
Designed for the professional mechanic. "

Would this be a fix also?

wow mac that is good info. i wonder if it will help out for the 80's.