Can My Problem Be The First Time It's Ever Happened?

BPinOC · June 11, 2009

I own a 2005 Chevrolet Silverado 2500HD crewcab 4x4 with an 8.1L engine and Allison transmission.

I did all of the research and determined that if I put 34 inch tires on the truck (stock is 30.5), I would need to change the gear ratio in the differentials to 4.56 (stock is 3.73) to maintain the stock rpm's at driving speeds. I learned that the truck's computer could be re-programmed with all of the new component data, and that I'd be able to drive the truck with no ABS or speedometer problems after the re-programming.

Well, I spent $3,000.00 on the re-gearing and electric lockers, and $1,500.00 on the tires. I then took the truck to the dealer to have the computer re-programmed. The dealer told me they couldn't reprogram the truck's computer because the tires and gears were outside their "programmable parameters". However, they suggested the truck's computer could be reprogrammed by an after market re-programmer (e.g., Hypertech).

I went online to buy a Hypertech programmer and found that it doesn't allow programming of gears and tires if the truck has an Allison transmission! The same is true for the other programmers I found.

I've searched high and low online for a solution, but I can't find anything even close to my problem.

I'm desperate because my ABS warnings are going off like there's been an attack on U.S. soil by some foreign enemy. I don't want to burn anything up (especially the Allison Transmission), and I certainly don't want to spend $4,500 to put things back to stock.

I can't possibly be the first person to have encountered this. Does anyone know what I can do? I would especially appreciate help from those out there that have had this problem and somehow had it fixed.

Help!

impalasspeed96 · June 11, 2009

Contact one of the tuners to the left. I'm sure they can tune for it. You can do a lot more through a laptop than you can on a Hypercrap. Don't freak, I'm sure you just need a custom tune.

GL.

BTW, I merged your two of your threads. You don't need three threads.

BPinOC · June 11, 2009

Contact one of the tuners to the left. I'm sure they can tune for it. You can do a lot more through a laptop than you can on a Hypercrap. Don't freak, I'm sure you just need a custom tune.

GL.

BTW, I merged your two of your threads. You don't need three threads.

Thanks for the help (though it's kind of difficult not to freak when I rely on my truck for a living and fear driving/ruining it!).

Anyway, you say "Contact one of the tuners to the left". I've never been accused of being bright, so forgive my question: Do you mean by "to the left" the banner adds on the left side of my browser window?

Thanks again.

impalasspeed96 · June 11, 2009

Yes, they are supporting tuners of this site, very reputable ones at that.

There is no fear of ruining it. Your speedo is just going to be off w/ the bigger tires. Althought I don't know why your ABS light is on. You say you had gears put in? Did they put a ABS reluctor in when they did it? That would cause you to have a constant ABS light if they left the reluctor out.

Stevens03 · June 11, 2009

I think the fact that the computer knows the tires/gears are different is why the ABS lights on. Custom tuner should be able to help set you straight.

Good luck

Hulk1999 · June 11, 2009

I agree with everyone. Anyone with a tuner program can change that stuff. My buddy did mine Monday after i put some new tires on. His software doesn't talk to the TCM. The ABS lights gonna come on because the tires are bigger than the factory max 285's. Mine does it all the time. ABS system works fine. I know Wester's Garage has a fix for it. Speedo is going to be off 5-10mph depending on your speed. Make sure you use a GPS system until you get your speedo fixed. That'll keep you from getting tickets. When you get the speedo recalibrated make sure you measure the tire yourself and not go off the sidewall measurement. Every company has different measurement standards. As far as Hypertech not being able to reprogram for tires and gears, i thought it said that it could even if you have an Allison. I thought it just couldn't change shift points. Hope this helps.

Hulk