silveradoman01

I really need some help!

I've got a problem with my trucks electronics regarding the tranny. The truck is a 2001 1500 4x4. My problem is that when I start off from a stop my tranny stays in first with the speedo at 0 and wont shift. Once it sits in 1st at 3000+ RPMs for a while it will slam into second and the speedo will shoot up to its reading then first gear again, second, first, second... All this time its changing from 1st to 2nd erradically as well as the speedo issue. Also accompanied with this problem is my ABS light along with abs activation under normal braking. The problem is 100% without a doubt electronic and has to do with my shifting, speedo, and abs. I've replaced the both VSS on my transfer case, had my tranny looked at by two shops, and had my ABS module refurbed all at a grand total of 700$. The last place was aamco which I hoped could read a code it might be throwing, those money hungry punks jumped straight to telling me its a mechanical issue and that I need to have the tranny dropped for 1000$. yeah of course it is.... I have a hunch that theres some more sensors im missing and could really use some help. Anyone who has the slightest input please reply, this is the third forum i've tried and im begining to loose my mind...lol. Thank you.

MDTAHOE

On the transfer case there is a front and rear propeller shaft speed sensor and a VSS. Are you postive you replaced the correct sensor?

silveradoman01

I replaced what I was told were the input and output speed sensors on the tail end of the transfer case. They are mounted on the top at slight angles. I wish I could find a schematic of the tranny to look for more sensors that might be causing it.
Thank you for the reply!

MDTAHOE

Those are the propeller shaft speed sensors. There should be one more on the transfer case. That should be the vss sensor

MDTAHOE

alldata.com
Will give you pictures of the locations. Wire colors to the sensors. And pictures of the connectors. Also it will give you a procedure to test the vss circuit.

cchinn

I can only tell you what I discovered on my 2000 K1500 Z-71. After putting in a replacement tranny myself, it started doing almost the same thing. No speedo, slamming into 2nd at 3,500 RPM, etc. After trying many things, I pulled off all 3 VSS electrical connectors (there are 2 on the back transfer case cone, and one over the front axle driveshaft output on the transfer case), pulled off the two 4WD actuator electrical connectors, and the other two wire connector over the tranny from the same wiring harness. Then I pulled out the big electrical plug from the tranmission itself. With every single wire disconnected from the tranny and transfer case, I blew out every electrical port with compressed air, then blew out every electrical plug with compressed air. Then I reconnected everything very carefully making certain it was well seated. Wallah -- she worked perfect. Not sure which plug had been contributing to the problem, but it was well worth the effort (for me anyway -- I can only hope you will enjoy the same result).

mikeSRusmc

I have a 2002 Chevy Avalanche Z71 4 wheel drive 1500 5.3 liter my transmission is not shifting out of first no speedometer I've replaced the wiring harness from the ECM to the transfer case I replaced all three speed sensors on the transfer case I even change the transfer case went through the transmission all is good in the transmission I have checked all my fuses my body control module my transfer case control module and still no shift no speedometer no cruise control I don't know what I'm missing if there's anybody out there that can help very much appreciate it I know it is not a mechanical issue as far as the transmission goes I've even checked my fuses

mikeSRusmc

I have a 2002 Chevy Avalanche 1500 4 wheel drive 5.3 L I cannot shift out of first gear no speedometer no cruise control have replaced ECM have replaced wiring harness from the ECM to the transfer case have replaced all three sensors on the transfer case have checked and replaced all my fuses replace the body control module replaced the speedometer instrument cluster and still I have no shift what could be the problem and how do I fix it

cchinn

It could be 2 separate problems. When mine quit shifting it was due to the linkage on the left side of the tranny where the shifter cable transitions out of its housing. There is a plastic framed housing that had a plastic protrusion broken off. Some creative bends of a piece of metal from my junk iron pile (it was about 1/8" thick x 1" wide and 4" long) combined with a couple of hose clamps to hold it in place fixed the shifting. That was well over 100,000 miles ago. It came loose once in that time and I put on new hose clamps. As for the speedo and cruise, I've no idea. And what fixed mine may not be your problem at all, but its worth a gander. I am not an expert, but I've got 340,000 miles on that 2000 Z-71 Silverado and am not tired of it yet.

Steven Weickert

I've been reading through these and I found them kind of helpful but when I finally found out what was wrong with mine I figured I'd let everyone else know what I found which is probably everyone else's problem to or most of them there is no power at the computer going down to the sensor on a 2002 model actually most of them for my Chevy says so when you testing you think they're supposed to be power everyone including me thought the computer had an issue but no there's not supposed to be any power this sensor is what makes the power and put the power to the ECM for the reading so I traced my wires at that point and looked at the connectors cuz that's the only thing I could find that might be wrong and found two prongs that were kind of pressed in a little bit from being removed too many times so when you remove a transfer case and put it back in or just connect the wires for any reason and then your Speedo doesn't work and it doesn't shift go to the wire connectors and check the actual prongs first thanks guys good luck