InTune Gear Ratio Changes?

[CrazyCooter]

I installed new gears in a 2005 1500 Silverado 4x4 and now it has the dreaded C0245 ABS code.

I can see that there is an 18% difference in wheel speed front to rear and from what I gather, anything over 15% will set the code. So obviously I need to adjust for the differences in driveshaft speed since it is read at the transfer case output shaft and now faster than OE.

On a recommendation from my wholesaler, I purchased a Hypertech programmer and set it to 4.56 gear ratio with no result. Called Hypertech and the smarta$$ tech guy told me despite their marketing hype, that function doesn't work......Luckily it looks like they may take that one back.

So....I call Diablo yesterday and tell tech guy my problem and he assures me that the Intune will change gear ratios....So I get it this morning and can't for the life of me find the menu to change gear ratio.

Now $650 deep in programmers and shipping, 7 hours in research on what to buy, diagnostic, and programming time, I still have a no solution. I have missed my delivery deadline and budget.....If I have a return customer by the time this is over, it will be a miracle! The front and rear gear job barley took that long to complete!

What am I missing guys?

[mikel]

pick the tune, then choose the option to modify the tune, go to axle ratio or speed calibration and set the axle ratio, then back out until it asks if you want to install the tune.

Thanks

[CrazyCooter]

I'm in that menu and there is no option for gear ratio.

It is the same menu as tire size calibration, shift points, fan turn on, etc???

[mikel]

from recollection its usually called axle ratio or speed calibration, but if you see tire size calibration, thats the ticket

[CrazyCooter]

I don't need to adjust for the tire size as the speedo is correct.

I need to adjust the gear ratio....... And I see no menu to change it.

[mikel]

OK, we're not on the same page...

Did you look in that menu?

Tire size and gear ratio (in the PCM's world) are one in the same, thus they are in the same sub menu in the tuner, please take a look.

[CrazyCooter]

You are correct, we are not on the same page.

The are not one in the same....

On a Chevy those speeds are read: front wheel speed by front wheel speed sensors located @ the hub assy and the rear wheel speed read from a sensor on transfer case output shaft AND is a calculated value directly proportionate to the ring and pinion ratio.

Change the ring and pinion ratio, and the front/back speed ratio the computer sees will be read as the % of gear change.....in this case 18%. it's no wonder why the ABS is freaking out! It thinks the rear tires are locking up compared to the fronts.

If I adjust the tire size, the speedo will be correct and wheel speeds will just read 18% less than they do now and I will still have the 18% difference front to rear setting the code within 1/4 mile.

I'm not a tuner, that's why I'm relying on you guys to fix this. The last Chevy I did a gear swap was only to 4.10s and it was apparently under that 15% magic number so it worked fine.

Bottom line is I can't let my customer take the vehicle without functioning ABS for liability reasons. Is this tuner going to do what your tech support told me yesterday?

Or am I stuck with another useless tuner?

[CrazyCooter]

I guess I should add that I installed 4.56's...

[novaks47]

Looks to me like Mike was saying just go ahead and choose tire size, or whatever option you have, and that should take you into another menu containing the option that you're actually after. If not, then I dunno.

[mikel]

You are correct, we are not on the same page.

The are not one in the same....

On a Chevy those speeds are read: front wheel speed by front wheel speed sensors located @ the hub assy and the rear wheel speed read from a sensor on transfer case output shaft AND is a calculated value directly proportionate to the ring and pinion ratio.

Change the ring and pinion ratio, and the front/back speed ratio the computer sees will be read as the % of gear change.....in this case 18%. it's no wonder why the ABS is freaking out! It thinks the rear tires are locking up compared to the fronts.

If I adjust the tire size, the speedo will be correct and wheel speeds will just read 18% less than they do now and I will still have the 18% difference front to rear setting the code within 1/4 mile.

I'm not a tuner, that's why I'm relying on you guys to fix this. The last Chevy I did a gear swap was only to 4.10s and it was apparently under that 15% magic number so it worked fine.

Bottom line is I can't let my customer take the vehicle without functioning ABS for liability reasons. Is this tuner going to do what your tech support told me yesterday?

Or am I stuck with another useless tuner?

the tuner corrects the speedo for gear/tire changes, it cannot change the ABS module or keep it from being upset about a % difference. I am not aware of any tuner that does this.
We have 100s (1000s?) of customers with re-geared GM trucks from 99-13, and I dont recall any of them complaining about this code. Its possible that most of them had taller tires making the effective gear ratio less 'steep'.

Now, are still not seeing the option to change the axle ratio setting in the tuner?
Once the speedo is correct, I dont think you'll have any more ABS issues, but we need to change the axle ratio setting to figure it out...

[CrazyCooter]

OK, to just test and satisfy everyone, I programmed the tire size. There were no other menus to adjust tire size anywhere to be found during that process.

Results are C0245 code returned....

Front wheel speed was 46mph, rear 55mph, and now speedo is inaccurate showing 65 mph with an actual GPS indicated speed of 50 mph.

The speedo has been accurate all along. I just need the calculation factor changed for the ratio changed.

Dealer says they can't do anything cause 4.56 wasn't an available ratio in that year/model.

There has to be a solution as I'm surely not the only one doing gear swaps and this is an old truck.

[CrazyCooter]

What I meant was....

There were no options within the programmer to be found that indicate gear changes are a supported feature. I'm a first time Diablo user, but know my way around many other tuners and pro grade scan tools. This shouldn't be all that difficult.

This truck is equipped with 35" tires and the 4.56 gear brings the RPM band back into the sweet spot. I'm quite certain that this is a common setup with the small block gasser crowd as I have been suggesting and installing this combo for 20 years. Everyone here in Cali installs a 6" lift and 35's.

I guess I'll have to look for another work around, but what do I do with this tuner I can't sell now? I thought I was safe when I called your tech support to verify the capabilities of this tuner BEFORE the purchase.

[Ill_Born_SS]

Cooter, I seem to recall seeing this once before.... The EBCM has to be flashed/replaced with one from a Yukon/denali they were available with the 4.56 gearing option. If you know a GM tech see if they could call GMassistance for you to get a positive fix that will work without wasting your/customer time. You can get rebuilt units for like 99.00 on ebay,I will see if I can find the link.

here is the link they are in cali. give them a call maybe they can help
http://www.shop.modulerepairpro.com/

[CrazyCooter]

I got the problem resolved it looks like....

I installed the Superlift Truspeed ABS re calibrator and the wheel speed sensors magically read within 1mph of each other.

I then had to set the programmer's speedometer calibration setting to 25.5" tires to get the speedo to read correctly.

The 87 octane base tune is horrible! The transmission shifts hard, erratic, and feels like it has 5 speeds with a really screwy torque converter lock up. I really don't have anymore time to spend with this tuner to dial it in, so I'm delivering it with the stock tune with the speedo corrected.

The guys at Diablosport really need to get it together......
1) The initial phone tech guy told me the Intune would set the gear ratio and it clearly doesn't.
2) The tech on this forum wasn't very informed or helpful to this situation.
3) The tune is horrible and suspect the trans and drivetrain would live a short life with it installed.

3 Strikes! You are OUT!

[mikel]

1. The tool WILL change axle ratio settings, if its not showing up, I will make you a custom tune, no problem.
2. I have tried to assist you the whole time?!?!?!? What more can I do for you?
3. We have 1000s of customers running that same tune, many of them here on this forum, a few of them trying to assist you here, I assure you there is something else going on there if it ran that poorly, we'd be out of business if we put out tunes like that.


Thanks