Chevy Corp Direct - Tire Reprogramming

[Little_Wiley]

Has anyone spoken with chevy corporate directly regarding reprograming the Allison for larger tires. We all know what the bulliten says however, wasn't it chevy themselve that put 37" tires on the COMBATT Tech Demonstrator vehicle for the military? I think they are just being buttheads here. I think they have all they need to do the reprogramming but just don't want to deal with it.

What really #)*($ me off is the fact that when you purchase the vehicle there is nothing said or written that says you cannot put any larger size tire on the vehicle. Then AFTER you spend money on the new rubber you hear them tell you "YOU CAN'T DO THAT."

I don't seem to remember chevy selling their older vehicle's with 33, 35, or 37" tires on them but if you did put them on it, they would take care of you for a price.

Guess we gonna have to just do a class action suit if they don't start supporting their customer's. This can be a safety issue on our part depending on how you use your vehicle.

Maybe I just had a bad day or Maybe I'm just tired of people taking my money and then not supporting me as their valued customer. If they have a VALID technical or saftey reason for not reprogramming the transmission, then I would happily say "FINE" but that's just not the case.

:mad:

[odoh]

In response to your question ~ I have not been able to locate anyone in the GM corp structure to talk to any of us. Do they talk at all?

[Mustfish]

I know just what you are saying. I put 265 tires on my new truck right after I got it. When it came time to tow nothing seemed right. Strange transmission shifting and the power was not there.Took almost 2 miles of Interstate 95 to get up to speed. My fuel mileage while towing a 4k boat was 9.7mpg. My truck has the 373 gears. The dealer looked at my truck and said the transmission had not been shifting from 2nd to 1st. Also said my new tires voided my warranty and to take them off. I ended up getting a new set of 245s simply to get rid of the firestones that came on it. Dealer gave me that same thing about not being able to reprogram Allison.

Jim

[TLA]

Any real ability to reprogram is going to have to come from the aftermarket.
I think that the real problem is that auto manufacturers have to certify emission levels for 50,000 miles for each drivetrain combination. The fewer of those, the less the cost. It is too bad that in addition, they make it harder and harder to mess with the code. I would be willing to bet that, as there is a growing market for this reprogramming, that companies like Jet and Hypertech will have a product by end of summer.

[Little_Wiley]

From what I can tell, regarding Hypertech, they will most likely not allow the reprogramming of shift points on the Allison transmission nor will they allow you the reprogram for your larger tires. Atleast they don't on the 8.1L/Allison version. On the 4L60/80 transmissions however, they allow you to change just about everything.

The Jet website has a chip for the 8.1L/Allison but I don't see what it does exactly.

[Billy14]

This is what my dealer had to say & I honestly believe they may be on cue having been subjected to the legal system myself with my business.

"GM could reprogram the ECM & TCM to accomodate different tire sizes. The problem IS, with the engine manufactured by Isuzu & the tranny by Allison both being covered by separate warranties, we now have a liability problem. If a problem arises, who will cover the affected or defective component, GM, Isuzu, or Allison?"

I was also told THEY are working on it & have a fix but it will be YEARS before the legal work will be signed, sealed, & delivered so all can enjoy.

Billy

[bbugg]

What I don't get is that I have seen brand new D/A's on dealer's lots with lift kits and Big tires. I saw one in Palm Springs, CA. with a 6" Pro Comp lift kit and 35 x ? Pro Comp tires. How can the dealer sell these modified trucks without a warranty?? They would have a tough time in court.
Please enlighten me... I hate my little wheels.

[SoMnDMAX]

What's the deal with the big tires?

I have put 18,000 plus miles on my truck since installing my 285's, with 6,000 of that running 265's (winter). Zero problems, no Allison issues (none that I didn't cause, anyway ;) ), and no engine power issues. Summer mileage on the highway is 19-21, winter highway is 16-19, summer city mileage is 16-18, winter city is 14-15. Towing my 7,000 pound trailer I'm getting 14-15, same as in winter with a four place sled trailer. I don't baby my truck either. :D

Very interesting.... :confused:

FYI, my truck was built 11-00, has all the latest updates, and currently has almost 21,000 miles on it.

[cmadmaxman]

My dealer told me that for libility they will make no changes beyond stock conditions! He told me that they will not even install a child safty seat! Don't sound like the dealers will be of any help. I checked out my speedo with the wifes Bonniville tonight and looks that its not that far off! Do notice a small change with shifting more with the 265's pulling the 9,000 lbs+ trailer this weekend, but nothing much worse than getting used to the 245's. Thinking about the Juice box to keep from so much shifting. :D

[DSLPOWR]

SoMnDMAX - I am in the same boat. There has been little or no difference in towing or fuel mileage with the addition of my 295's. Truck shifts/pulls/hauls fine. I frequently haul a 10k fifth wheel too. I guess I must be missing the point. :confused: Must just be a difference in truck/driver or something. :rolleyes:

[ndamico]

DSLPOWR,

What rims are those on your truck with the BFG's? what did you have to do to get them to fit inside the fender wells?

thanks

[Diesel_D]

I drove my 02 dmax/allison 30 miles in stock form. Then had a 6" lift and 35's installed. I'm at 4k and she runs like a raped ape. I spooled her up to 2k and let it rip the other day and she spun the 35 rather well. :D Did i mention i love this truck. :D