$0D 4L60E shift adjustment

**Kitch** · 06-23-2016

I've recently bought a 95 GMC Yukon with a BJYL PCM $0D bin and I've been doing a bit of driving and data logging.
One of the annoying charaterristics the truck has is to hold onto 4th gear as I moderatly accelerate from 40 MPH to 60 MPH up an onramp. The engine is lugging and goes better if I manually change from "D" to "3" as it goes up the onramp, is there something I can change in TunerPro that will make the trans downshift from 4th to 3rd sooner as the MAP and throttle position go up?

**96lt4c4** · 06-23-2016

Change TPS to enable kickdown mode to about 80% and Change TPS to disable kickdown mode to 70-75%. Moving them down more will cause it to downshift even earlier.

**lionelhutz** · 06-23-2016

There should be a shift table using speed vs %TPS. Modify it to change the shifting.

What I have done before. Manually select each gear and then use 5% to 10% TPS increments and determine the steady speed the truck drives for each throttle position. Take that data and add about 5% to the TPS values and use it to create the upshift curve. Add about 10% to the %TPS values and use it to create the downshift curve.

Example
30% TPS in 2nd gear = 40mph.
Enter 40mph @ 35% TPS for the 2-3 up shift.
Enter 40mph @ 40% TPS for the 3-2 down shift.

If you are driving 40mph in 2nd and over 35% TPS you are accelerating so stay in 2nd. If you are driving 40mph in 3rd and press the throttle over 40% then downshift to 2nd and accelerate. If you are driving 40mph in 2nd and let off under 35% TPS then you're going a steady speed so shift to 3rd.

Once you start the above, you might find you "pull back" the curves to be less than the 5% spreads to get even more response or "push out" to get less response.

**96lt4c4** · 06-23-2016

You could also download some stock LT1 Corvette and Camaro bins. Compare the transmission shift points to yours. The old LT1 Corvettes had some pretty aggressive transmission shift points. Even more aggressive than the LS1 Vettes did.

**Kitch** · 06-23-2016

Thanks for the reply's, you've given me some things to have a look and hopefully try out over the weekend. Any idea what the shift table might be called in TunerPro, I had a quick look but couldn't find anything that looked quite right?
I also had a look at Bluecat transmission software but I couldn't find a tutorial that showed me how to use it, I'm guessing it's a quicker way to modify the shift table.

**Fast355** · 06-24-2016

Originally Posted by Kitch

Thanks for the reply's, you've given me some things to have a look and hopefully try out over the weekend. Any idea what the shift table might be called in TunerPro, I had a quick look but couldn't find anything that looked quite right?
I also had a look at Bluecat transmission software but I couldn't find a tutorial that showed me how to use it, I'm guessing it's a quicker way to modify the shift table.

Bluecat is very straight forward. Hover over the parameters and it has an explination of what it does. Been using it for a few years here.

**Kitch** · 06-24-2016

Hi Fast, is there somewhere I can find some good starting values to input into Torque converter table for my 1995 Yukon and can you recommend a good tutorial on how to best use the Bluecat trans table generator?
Are the tables that I've shown the best ones to adjust in TunerPro?

**lionelhutz** · 06-28-2016

PWM is just how hard it locks up. You'll have to experiment with the 700R4 tables.

**Kitch** · 06-30-2016

Okay so I've had good success with the 4th gear shift tables and the changes I've made to my 3->4 and 4->3 shifts have worked but I've had no luck with TCC control.
I made a line graph of my settings and then manually plotted the results of a logged test drive shift points onto the graph and as it felt in the truck the graph showed TCC lockup and unlock was pretty much on 4th gear upshift and downshift, not the TCC lock and unlock points shown on the graph.
Any ideas how I could make TCC work as per the graph, am I using the wrong table?

**lionelhutz** · 06-30-2016

What's in the TCC Engage/Release Threshold table?

**Kitch** · 06-30-2016

Nothing?

**Kitch** · 07-01-2016

Okay, so instead of using the TP search function I manually looked through the Parameter tree and under the heading "TCC engage/release thresholds" I found the two attached tables. I've now altered those two tables because they look like the best candidates to change the TCC lock/unlock and I'll try them out tomorrow, here's hoping they work.