LMM: Speedo Recal

[02CCSB]

Having a bit of a battle, wonder if anyone has conquered this.

The truck is an 08 LMM, runs on 37" tires & just swapped to 5.13 gears.

Shift points are fine & ABS lights are off with 5.13 in the axle ratio.

At 30mph on the speedo, the actual road speed GPS'd is 38mph.

Tried adjusting the gear ratio calculation, speedo gets close, but then I'm throwing ABS codes.

Any help would be appreciated

 

[clrussell]

I think lmm gets pissy if you try to calibrate over a 34.5" tire

What's it do it you set it to factory settings? How bad is the speedo?

 

[56taskforce]

What are you calibrating with. Mine was attempted with hypertech speed recalibrater and was a fail I put up with the ABS and brake service lights till I went EFI Live all is good now.

 

[02CCSB]

It's EFI. I've done tons of trucks but nothing with this big of a combination.

Need to spend more time with it playing with both the ECM & TCM & see what happens.

 

[56taskforce]

I was just thinking because I am very close to 37s with 4.56s. I thought about 4.88s wow 5.13s that's deep for a diesel.

 

[02CCSB]

Typo, its got 38s on it....not to mention just about everything else under the sun...

 

[THEFERMANATOR]

Theres no need to touch the TCM. And as stated above, the LMM gets pissed off if you try to recalibrate for to big of a tire change. Your problem is you can recalibrate the speedo, but you CANNOT recalibrate the ABS. With an LMM set it for a 34.5" tall tire and you have to live with it.

 

[Awenta]

Holy crap. 5.13? That's like driving on ice, no?

Sent from my SM-N910V using Tapatalk

 

[Chevy1925]

Theres no need to touch the TCM. And as stated above, the LMM gets pissed off if you try to recalibrate for to big of a tire change. Your problem is you can recalibrate the speedo, but you CANNOT recalibrate the ABS. With an LMM set it for a 34.5" tall tire and you have to live with it.

His problem is compounded with the gears. Gunna need a tech2 to flash into the abs module via the thread Mcrat posted a long while back. I can't remember what I flashed mine as but after flashing that and tweaking my speedo in the ecm, all is good. I wanna say it was for 285/75r16 tires is what I flashed the abs to