SPEEDO 15-20 mph off, abs light,

Injected79 · Jan 19, 2013

Hey guys, I bought a blown up 2004 6.0 a little while back, Long story short i wasnt able to drive the truck pior to buying it. Now its all back together, lifted on 35" tires. I got it out yesterday for the first time and the speedo is 15 to 20 mph at 40 mph by my gps. IF the speedo reads 45 to 50 then im running around 80 by the gps.

The truck had a noise in it, i found the rear pinion was loose, at this time i dissassembled the rear diff to inspect everything, only other damaged i seen was the case of the carrier had some cuts in it looking like it came from the pinion. I tightened the pinion back up, noise is gone but speedo is still no where close. While i was there i cleaned the speed sensor up checked bearing and so on.

Now on to the next step. I got tunes from Matt for the truck, and iv been going through the adjustments on the sct, i have programmed it with stock tires up to the biggest tires it offers on the tuner at 505 revs per mile with no difference. So i also tried the gear ratio adjustments, from a 3.08 gear up to a 5.13 gear with the same results. I have AE software, and the speedo is reading the same on the dash as what the software is picking up on the computer. This tells me the dash cluster is ok, and the speed sensor is working.

Any ideas on where to go from here?

HOOV3R · Jan 19, 2013

Adjusting on the sct changes the points for shifting, not the dash.

Injected79 · Jan 19, 2013

i spoke with larz, he helps matt with the tuning, he was saying that the tire rev section, should adjust the dash read out. and on that same note the shifting never seemed to change with the transmission no matter where i had that set.

hawgdoctor · Jan 20, 2013

If you've got we then you can change the tire size setting also. You'll have to go into the abs module, but once yih okay with that you can get it right.

sent from the shop making things fly.....

Injected79 · Jan 20, 2013

well i got into the ABS module with my AE today, changed the tire size up to 40" tires and still same results. Im starting to wonder if the tone ring hasnt been changed prior, and they put the wrong one in it. Im going to have to pull it again and count teeth.

Injected79 · Jan 21, 2013

bump for other ideas

neverkickn · Jan 21, 2013

you already said what i was thinking. It's an easy mistake to make.

vcassens · Jan 21, 2013

I had the same problem with my 04 when I pulled the speed sensor out of the rear end out was split from the tone ring. Turns out the carrier bearings where bad

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Injected79 · Jan 29, 2013

pulled it back apart today, tone ring is in good shape and is the correct 120 tooth count, speed sensor also tested good.
Is it possibly the abs module would need flashed or replaced? Could it be giving a bad caculation to the speedo?

Injected79 · Feb 2, 2013

did some more data reading on it today, and the right front speed sensor is inop, has a new wheel bearing and speed sensor on it also still not working. but here is what i found out today.

when I start the truck and bring up values of all 3 speed sensors all 3 speed sensors read 3.

while driving the truck is what thoughs me off here is a link to what i pulled from the a/e

i forgot to mention the left front wheel speed sensor is the closest to accurate, at 35 mph it is with in 2 or 3 mph vs the gps, and the rear diff speed sensor is of course idenical to the speedometer reading on the dash

Injected79 · Feb 2, 2013

ok, sorry, the link to the a/e readings wont post on here, but here is a link to psn. where the link copied ok.

It is in post #11

http://powerstrokenation.com/forums/showthread.php?p=1989018#post1989018

:shrug: