Speedo Reads Zero, Wont Shift Out Of First, Abs Vibrates Pedal

Zed71 · March 23, 2011

Hi Guys.

I have a 2007 GMT-900. Z71 w/ 5.3L

I recently replaced my front rotors with slotted discs.

About 3 weeks later my ABS started to go on at low speeds just before the complete stop (it would vibrate the pedal just before stopping)

A few weeks after that, I was driving along and after a complete stop my speedo started to fail and read zero and the truck would not shift out of first (it would rev to 6000 rpms)

The truck moves, probably goes about 15mph but reads zero, and RPMs skyrocket. This issue does not occur if I am out of first gear, and driving. Only after a complete stop.

Another complete stop seems to reset everything and it works again.

The ABS issue happens all the time, but the speedo / shift issue only occurs once in a while. Maybe 3-4 times a week.

I have replaced the slotted rotors with standard ones, but the ABS and speedo / shift issue still persists.

Anybody else have this problem?

[email protected] · March 23, 2011

The speedo shift issue sounds like a bad vss sensor to me. And the abs kicking in earlier than normal sounds like bad or dirty front vss sensors

Zed71 · March 24, 2011

The speedo shift issue sounds like a bad vss sensor to me. And the abs kicking in earlier than normal sounds like bad or dirty front vss sensors

I replaced the vss sensor in the transfer case today. I haven't had the speedo issue happen yet, but I still have the abs issue.

A front VSS eh? Where is that located? Know the part no.?

My truck does not have stabili-trak. Is there any other VSS sensors on my truck other than the transfer case? My dealer's parts guy said that my truck only has one, and that's the transfer case one?

It's awesome trying to fix an electric issue when there's no codes being thrown

[email protected] · March 24, 2011

Yeah, there's also one at every wheel on a gmt-900.

wildmanwill · January 4, 2012

Did you ever successfully resolve this issue? I ended up here after googling the symptoms of my truck. I already replaced the speed sensor on the transfer case last week but that did not resolve issue. My truck is a 2007 GMT900, completely stock and I am experiencing the won't shift out first, speedo reads 0 mph thing after a rolling stop, and about that same time started experiencing the pedal pulsation at the end of a normal stop. Shifting issue occurs at least once per trip with the truck, doesn't matter if the truck is warm or cold. Sometimes the tranny would catch again in first, other times it would rev out like it was neutral. Only way to reset it and resume normal shift pattern it to come to a complete stop. I tried playing around with the gear selector but that didn't matter, have to stop completely. Thanks in advance.

wildmanwill · January 5, 2012

It's at the dealership now. Tech said that there are only 3 vss on the truck, one at each front wheel and the one at the transfer case for the rear wheels. I have not heard anything on a diagnosis yet.

Stevens03 · January 5, 2012

I just had a similar issue with my wifes car.

Speedo was dead, and only had second gear (limp mode). It was an EASY fix. All that needed replaced was the output speed sensor on the transmission. $24 and 10 minutes labor and it was golden. Hopefully it's as simple as that for you.

wildmanwill · January 5, 2012

From what I gather the truck has 3 speed sensors, one on each front wheel and one on the transfer case. One on transfer case was out of spec and replaced - I believe that this sensor is the equivalent of the output speed sensor on your wifes car?

newdude · January 5, 2012

From what I gather the truck has 3 speed sensors, one on each front wheel and one on the transfer case. One on transfer case was out of spec and replaced - I believe that this sensor is the equivalent of the output speed sensor on your wifes car?

I believe if its a stabilitrack equipped truck before a certain year, i think 2009, its a 4 channel ABS system, with 4 wheel speed sensors. I believe 2009 or 2010 and up, all configurations are 4 channel system, and 2011 HD and up are now 4 channel ABS. Regular cab before 09-10, HD before 11, and GMT-800 are 3 channel systems. I may be wrong somewhere in my timelines however.

wildmanwill · January 5, 2012

My 2007 Extended Cab did not come equipped with Stabilitrack. Don't have the button or the light for it either.

I had to go drive the truck for the dealer as they could not duplicate either of the symptoms. After about 20 minutes of driving around with the tech I got both things to happen.

Stevens03 · January 6, 2012

Thank goodness the issue re-occured with the tech in the truck. Now maybe you'll get some where.

It's odd your truck doesn't have stabilitrak. I know a few of them that came without it, My 07 Vmax had it but it was an SLT with NHT max trailer package.

wildmanwill · January 6, 2012

Broken output shaft bearing snap ring in the transfer case. Replaced with an updated hardened steel one, so I've been told.

"Inside the transfer case the output shaft snap ring broke - metal parts in transfer case cleaned the snap ring parts and replaced/cleaned. Re-assembled the transfer case -- road tested"

Still would have been nice to have some followup/feedback from the OP as to what his problem was and what the resolution was...

wildmanwill · January 8, 2012

Got the truck back and put about 75-100 miles on it so far without incident...

Stevens03 · January 8, 2012

jwilley · January 13, 2012

My wife drove mine at 45MPH in 4x4 for about 5- miles couple weeks ago and started having problems with gage bouncing around. This was paired with the abs and park/brake lights. Pulled battery cable and reset system was good for 40+ miles then ABS lights popped on and speedo went crazy causing the tranny to shift. had to stop put it in neutral and start back out. I did notice this becomes reoccurrent when hitting a sudden bump. Does this sound like the issue you were having? Already changed the VSS. It's and 02 2500HD.