Speedometer doesn't work and transmission doesn't shift gears.

dfrinzi
115

Asked by dfrinzi Nov 25, 2011 at 07:33 PM about the 1999 GMC Sierra 1500 SLT 4WD Extended Cab LB

Question type: Maintenance & Repair

The speedometer stays at 0 all the time.  When the transmission is in drive it won't come out of 1st gear.  Reverse works fine, and if I manually put the transmission in 1st or 2nd it works fine.

1999, Auto 4wd, automatic, 5.3L

24 Answers

Dan Nash
345

Vehicles transmission output speed sensor faulty

15 out of 15 people think this is helpful.
You think this is helpful.
Best Answer
dfrinzi
115

I replaced both output speed sensors, and also swapped them around with the old ones, no luck. This problem started after I removed the transfer case to install the wear plate and replace the actuator motor, not sure if that has anything to do with it. The 4wd works fine. Thanks

11 out of 11 people think this is helpful.
DanTheMan5160
125

It's Vacume or electrical is your problem or passing gear cable.If the passing gear cable is broke,unhooked at the throutle body or unhooked inside the transmission would cause that as well.Yep,Vacume could be if your 4wd works under vacume hoses or lines.If your 4wd is electric .You either got a vacume line crossed/wrong.Or leak in a vacume line or unhooked.It's not a speed sinser.Transmission Shifts either from Vacume or electrical.Sounds like to me from playing around with the transfer case you made a mistake.

5 out of 5 people think this is helpful.
kemuhps
200

2003 Sierra-My truck is doing the same thing- speedo reads zero and won't shift out of first. I cleaned the MAS, replaced shift sensor, made sure trans fluid was full, disconnected and reconnected the battery, and now I am thinking of replacing the stepper motors for the speedo but don't think that covers the shifting issue. ANY HELP welcome!

20 out of 20 people think this is helpful.
Joe Bartlett
495

vehicle speed sensor,on the rear of the transfer case ,if you got no speed o your truck wont change gears

15 out of 15 people think this is helpful.
rberber
110

I replaced the vehicle speed sensor VSS then unplugged the vehicle speed sensor buffer VSSB (a 3 inch square flat white plastic sensor box) located behind the glove box, I unplugged it and waited 5 minutes before plugging it back in. I also pulled the brake fuse and did the same thing, waited 5 minutes then plugged the fuse back in. The result was successful, the tranny and speedometer work correctly now!

11 out of 11 people think this is helpful.
You think this is helpful.
tonypergar
10

I did what you said but n luck

tonypergar
10

replaced the vss then unplugged the buffer waited 5 minutes then pulled the brake fuse and waited 5 minutes but no luck transmission still not shifting and no speedometer.

1 out of 1 people think this is helpful.
Willie Gillispie
0

same for me no help at all

juggaloscorpio
35

check the ignition switch harness for power drops across the white wire and the pink wire... it is a know problem for the harness to lose power there and causes loss of transmission shifting along with instrument cluster failures.

3 out of 3 people think this is helpful.
Raymond McNeil
30

My 2000 Tahoe LT 4×4 has that not changing gears issue. Put it in drive - nothing, go to 1stthe and it grabs, you manually shift it, works great, even drops down gears and then changes great. The main problem is after I manually shift it, I come to a COMPLETE stop, it goes right into basically neutral, but if I don't COMPLETELY stop it keeps pulling. Once that happens, I have to manually shift it out again. Does anyone have an idea of what themayis be? issue

3 out of 3 people think this is helpful.
Jeffrey Kill
60

its more then likely the seo ign 10 amp fuse in the fusebox next to driver door the fuse looses power causing instrument panel failure and transmission goes into a nuetral state

1 out of 1 people think this is helpful.
Terry Huffman
50

You said check the ignition switch harness for voltage drops I think that could be my problem because when I check the buffer voltage I only get five volts at the speedo buffer I thought I was supposed to have at least 12 volts is that correct? Do I possibly have a bad ignition switch ?

4 out of 4 people think this is helpful.
William Zierman
120

I just replaced my trans in 01 Yukon. I'm having the exact problem originally stated by dfrinzi. speedo not working and won't shift out of 1st in od but I can manually shift from first to second but not 3rd or fourth. Jw if this problem was resolved and how to go about it thanks.

12 out of 12 people think this is helpful.
Jeffrey Kill
60

Speedo sensor in transfer case I replaced it now it shifts fine speedometer works like it should and I haven't had any other problems

1 out of 1 people think this is helpful.
Richard Longacre
30

I had similar problem and mine turned out to be the safety neutral switch.

3 out of 3 people think this is helpful.
Jeffrey Kill
60

I retract my last statement worked good for almost 2 weeks then started acting up again I'm at a loss

3 out of 3 people think this is helpful.
bildur1
10

I found a TCM fuse (10) under the hood that was blown. Was hard to tell for certain but I replaced it and the speedometer and transmission are working properly now

1 out of 1 people think this is helpful.
cesale
20

I have a 2005 Tahoe and my speedometer and gas gage doesn't work gas gage stays buried over full and speedometer stays at zero any ideas?

2 out of 2 people think this is helpful.
William Zierman
120

Speed sensors on the top side of transfer case, one or the other is bad or unplugged

Mark Lutz
0

I have no power to the 10 amp Trans fuse. What color wire at the in essence which supplies the power to that wire? 95 gm 1500 4x4

Mark Lutz
0

ignition switch damn autocorrect

Steve Mcmillan
0

just replaced the trans cooler lines due to a leak and now my 02 trailblazer wont shift and speedo not working all the time

Terry Huffman
50

I replaced my ignition switch and problem was solved I wasn't getting 12 volts to the speedo buffer behind glove box

1 out of 1 people think this is helpful.

Your Answer

Add photo

Related Questions

Sierra 1500
Looking for a Used Sierra 1500 in your area?
CarGurus has 55,352 nationwide Sierra 1500 listings starting at $975.
ZIP:

Search GMC Sierra 1500 Questions

GMC Sierra 1500 Experts

#1 dragonflyoffshore
dragonflyoffshore
Reputation 2,600
#2 John Saffrahn
John Saffrahn
Reputation 1,820
#3 Glenn Clingenpeel
Glenn Clingenpeel
Reputation 1,340
View All

Related Models For Sale

Used Chevrolet Silverado 1500"
1,787 Great Deals out of 142,118 listings starting at $1,500
Used Ford F-150"
2,205 Great Deals out of 100,555 listings starting at $1,300
Used Dodge Ram Pickup 1500"
567 Great Deals out of 10,867 listings starting at $1,990
Used Toyota Tundra"
440 Great Deals out of 17,444 listings starting at $2,499
Used Toyota Tacoma"
593 Great Deals out of 24,235 listings starting at $1,895
Used Chevrolet Tahoe"
687 Great Deals out of 24,212 listings starting at $1,955
Used GMC Yukon"
236 Great Deals out of 8,199 listings starting at $2,495
Used GMC Yukon Denali"
146 Great Deals out of 7,099 listings starting at $1,495
Used GMC Sierra 2500"
162 listings starting at $5,900
Used Jeep Wrangler"
688 Great Deals out of 46,748 listings starting at $1,800
Used Chevrolet Camaro"
472 Great Deals out of 34,467 listings starting at $1,595

Used Cars For Sale

2015 GMC Sierra 1500 For Sale
33 Great Deals out of 38,615 listings starting at $25,995
2014 GMC Sierra 1500 For Sale
76 Great Deals out of 3,751 listings starting at $17,900
2013 GMC Sierra 1500 For Sale
116 Great Deals out of 2,538 listings starting at $16,995
2012 GMC Sierra 1500 For Sale
92 Great Deals out of 2,079 listings starting at $11,987
2011 GMC Sierra 1500 For Sale
83 Great Deals out of 1,951 listings starting at $10,490