u7198 2000 silverado transmission problem

[michigan2500hd]

Just downloaded the 87 performance tune 3-24-07 and for the most part i am happy with it. I have had other tuners and 3 pcms tuned by a company in canada. As far as i can tell power gains are as good as the custom tunes i have had. The problem i am having is with the shifting. If i put the go pedal all the way to the floor the trans kicks down like it should but after that it shifts super hard. Even after coming to a stop and taking of slowly it continues to shift so hard i am afraid something will break. If i pull over a shut the truck off for 5 minutes or so it will shift fine untill i floor it again. I tried uninstalling the tune but then it shifts very slow and it feels like there is two parts to each shift. with the 2-3 shift the worst. I put the tune back in and quickened the 1-2 and 2-3 shifts by 5% and all was well untill i put the pedal to the floor and the whole shifting problem happened again. All seemed fine untill i put the tuner on it, any ideas?
GM02 Predator 2.13 serial no# 002401 158286
id no# 2ad207c4e7d6ecc7

[bretter1]

I am having the same problem with my 1999 Silverado with a 5.3L vortec. But, the problem comes up sometimes even when I haven't been driving hard. I have to stop and turn off the engine and wait for 10 to 15 seconds and then restart the engine. The trans will shift normally. I have tried several times to remove the tune and the trans will shift normally. When I reinstall the tune it will start shifting hard again. Is there a defect with the tuner or what?

[mikel]

We can try writing you guys a new custom tune to address these issues.
Send me your original backup file with a list of mods to the truck and I'll get you taken care of.

Thanks

[bretter1]

Mike,
When you say original backup file, do you mean my original truck's program or the the tune of my predator? I have a 1999 Silverado Z71 4WD with autotrack and a 5.3L. My predator is a u7198, #157846. I have been running the 87 Oct program. The only modification to the truck besides the tuner is a K&N cold air intake. Can you give me instructions on how to download the information you need? Thanks!

Brett

[mikel]

Yes, a copy of the original program.
I am emailing you a set of instructions now.

Thanks

[Aaronr]

I have similar problem. I have that problem with part throttle. Sometimes shift nice firm and quick and something really hard. I have over 120k on my truck.
I have a 2002 Chevy truck with 5.3L
Predator u7198 2.13v
The shift timing set at -25%
The wot is set at 25%
Part throttle shift was at 15% but now is at 12%
If I send you my back-up what are you guy going to do with it?
Do you guy's change the shift points or lower the tranny line press?

[mikel]

I have similar problem. I have that problem with part throttle. Sometimes shift nice firm and quick and something really hard. I have over 120k on my truck.
I have a 2002 Chevy truck with 5.3L
Predator u7198 2.13v
The shift timing set at -25%
The wot is set at 25%
Part throttle shift was at 15% but now is at 12%
If I send you my back-up what are you guy going to do with it?
Do you guy's change the shift points or lower the tranny line press?

We can modify the tune to lower the line pressures.
Have you modified the part throttle line pressure settings in the Predator?
Try setting those to a negative setting to see if it helps.

Thanks

[Aaronr]

Do your know why only does it somethimes? Most of the time it shift graet.

[Aaronr]

Sorry for so many questions. When i first got this truck from dealer it add shiming when shifted from 1 to 2. To fix the shiming they promble add line press I'm not sure. I guess just take more out "pts".

[michigan2500hd]

We can try writing you guys a new custom tune to address these issues.
Send me your original backup file with a list of mods to the truck and I'll get you taken care of.

Thanks

Thanks for the response. Although i didnt recieve an email from you saying how to get the orignal file to you. Do i have to purchase a cable to hook it up to my computer?

[mikel]

Sent!

Thanks

[shortrc]

I sent gary@diablosport my tune this evening I was just wondering if you guys had had any success with the updated tunes for your trucks yet?

[michigan2500hd]

I sent gary@diablosport my tune this evening I was just wondering if you guys had had any success with the updated tunes for your trucks yet?

I am sorry,but no, i have been so busy lately with work and helping neighbors with stuff that i havent looked into the complicated instructions to send in a back up tune. i do need to cause its no fun having a tune if you cant step on the gas,lol. Hopefully this weekend i will.

[seltaeb]

I installed the 87 oct tune and now I also am having the same problem with shifting after you go WOT. I tried to adjust the shift time and pressure but it is still doing this. What changes do you recommend to correct this problem, or should I email the tune to you to fix it. I am worried about if this is going to hurt the transmission.


2000 GMC Sierra
5.3l auto 2wd
Rev 2.13
u7198

[mikel]

If you lowered the WOT shift pressures all the way and it did not help, email me a copy of the original backup file and we can try to help you out.
I am emailing you instructions on how to do this.

Thanks