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Tuner
Some help with my 2-3 shift: towing mode
I was hoping someone could give me a hand with this one. File attached.
In tow/haul mode at about 32 - 40% tps I have a very sloppy 2-3 shift. It is tune related, aka something I've done as it does not happen with the factory tune or out of tow/haul mode with the same tune.
I'm sure it is obvious but I'm just not seeing what I've messed up. Here is the scenario.
Between 32 and 40% tps, about 40 - 45 mph when it goes to shift if feels like the following is happening. All this happens within a second or two.
1. The TC disengages, rpms go up
2. The shift to 2-3 happens but is very soft and slow
3. The TC engages, rpm's go back down.
My 1-2 shift is real quick and firm, no slop.
If I go out of tow haul mode the 2-3 shift is real quick, could be a little firmer.
I'm just not seeing what I dinked.
Thanks for any feedback.
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Your tow/haul 2-3 & 3-4 shift pressures are lower than the normal shift pressures.
Post your stock tune.
Russ Kemp
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Tuner
Thanks Russ, I always appreciate the help.
Sorry for the delay, we are in the middle of yet another Disney trip. She towed nice except for the 2-3 shift.
I took a quick look at my factory file and the pressures are the same, however I think I may have found my goof. I have the TC release speed in 3rd lower than where I come out of second gear.
I'm going to put the factory release speeds back in the table.
I still welcome your input. Going to be a few days before the vacation ends before I can test.
One more final question, if I may. I live in very flat area of Florida. What do you think about adding TC lockup in normal mode for second gear?
I hope all has been well.
Hank
Last edited by FGCUhank; 02-28-2009 at 03:31 PM.
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Make the changes to the shift pressures & TCC lock up speeds as shown.
Did you install taller than stock tires? Is your speedo accurate?
Russ Kemp
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Tuner
Hi Russ,
Sorry I missed this reply. My tires are "factory size" but based on the manufacturer specs they are 1" larger than the prior brand. I put some stock sized BFG AT's and a 2" lift kit on the van.
I made the adjustment in the speedo settings for tires size and it is very accurate to my GPS.
I'll make the changes you recommend and post back.
Thanks again.
hg
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Tuner
Hello Russ, Thanks again for the help with this. I have keyed it all in and am loading it in the am.
Since you are the expert here, I have a question regarding the TCC settings for performance.
I notice you pulled all the TC lockup out of second gear. Why did you choose to do that?
Note: the factory program also had TC lockup in second gear but had that same sloppy 2-3 shift feel that started this thread.
Thanks for the input.
Ok, a second question, when I'm not towing and throw the towing switch the van really comes off the line and the TC lockup in 2, 3 and 4 really pulls good. Any logic why not to put TC lockup in 2nd for normal driving?