Diablosport Forums

Hey Mike, just wondering here.....could the problem be with the 87 tune and can i uninstall that then adjust the shift firmness on the stock tune? I would like to have the tune in it but with it shifting so hard i am afraid something is going to break. I looked at the instuctions for sending you a back up stock tune from the predator but i dont have the 9 pin adaptor or the equipment to power it up once i have it connected to my pc. Is it the dealers responsability to do this for me? ( the place i bought the Predator from )

No, the dealer is not responsible for that.
You can get those cables at Radio Shack using the part numbers 273-1717/273-1776 for the power supply and tip adapter, and 26-117 for the serial cable.

You can try setting the factory hp tune shift pressures to see if it helps, but there is no power gain in that tune.

Thanks

mikel wrote:No, the dealer is not responsible for that.
You can get those cables at Radio Shack using the part numbers 273-1717/273-1776 for the power supply and tip adapter, and 26-117 for the serial cable.

You can try setting the factory hp tune shift pressures to see if it helps, but there is no power gain in that tune.

Thanks

Thanks for the part numbers Mike. Tried adjusting the factory tune shift pressures yesterday but it didnt seem to do much. With the factory tune reinstalled its really slipping during shifts but with the 87 tune its fine untill you give it any more then about half throttle. Then it slams the gears super hard and wont quit doing that untill i shut it off for a few minutes. I will try to pick up the cables tomorrow, thanks again

I have a 2000 Silverado 5.3 and I am having these problems also. I have the u7198 2.13. It shifts great at first, then when I go WOT it shifts fine, but after I go WOT it will shift very hard from then on. I had my trans rebuilt and it does have a shift kit if that makes any difference. I'd like to get this corrected b/c it feels like its gonna tear something up shifting hard.

everything I have read around the forums says that you should do one or the other, but not both - meaning, either get a shift kit, OR adjust the tranny shifting via a tuner... but don't adjust the tranny shifting with a tuner AND get a shift kit, as it will/could cause issues.

again, this is what I have read on several different forums, and I have no personal experience with this... just my 2-cents.

Mattman84 wrote:I have a 2000 Silverado 5.3 and I am having these problems also. I have the u7198 2.13. It shifts great at first, then when I go WOT it shifts fine, but after I go WOT it will shift very hard from then on. I had my trans rebuilt and it does have a shift kit if that makes any difference. I'd like to get this corrected b/c it feels like its gonna tear something up shifting hard.

I emailed you instructions on how to save your backup file.
Email me this file and include any info related to the issue and I will have a tune made for you to address the shifting issue.

Thanks

I did not recieve the instructions, could you send them again to [email protected] Thanks

i just installed the 87 tune in my 00 chevy 1500 and my trans shifts good sometimes and the other times it shifts really hard i have ths diablosport u7198 i need some help

I also installed the 87 octane tune in my 2000 chevy silverado 1500 5.3l and sometimes when it shifts I think my transmission is going to drop out of the truck. I am getting ready to tow a car to florida and I am scared to run this tune , but like the extra power please help me.

I lowered the line pressure on WOT and part throttle. Did not help at all. I returned to stock tune because transmission sounds horrible when shifting it makes me cringe every time it shifts. Please give me some advice and info on how to send you the tune.

Lyle are the fluid levels ok in the transmission ? When was the last time your tranny filter and fluid were changed? Sparatic shifting probs could be a sign that things in the tranny like shift solenoids are maybe gummed up.

Like on the other thread I posted on...I had this same problem. I got a custom tune through johan and he put some shift tables back to stock...and it worked. Before that I tried everything just like you guys did...nothing worked except Johans tune or putting the tune back to completely stock.