Instrument cluster/Transmission shifting-Same Issue??

[CO-Tahoe]

I just purchased a 2000 Tahoe z71 knowing that it had a few issues. I have done a bit of research and there are a few right ups about a possible short causing issues with both transmission shifting as well as instrument cluster issues. What is a little strange is that the bottom portion (Oil pressure and Temp.) of the cluster seems to be functioning okay but the top (fuel and volts) are very wacky, also I have a tach but no speedometer. The transmission is in what seems to be "limp mode" (2nd gear only) except when down shifting I get 1st and 2nd but back up to 3 or D I shift back to 2nd. I plan on replacing both shift solenoids this weekend but was wondering if anyone thinks that these might be related at all? One other thing is I did have a ABS Light and service engine light on so I took it over to the parts house and they said it was throwing a bad ABS Wheel Sensor code. I played with the connections and got the ABS light to go off but still have the service engine light.
Any advice or input is greatly appreciated.
Chad

 

[Martinjmpr]

If your transmission only works in R, 1 and 2 it sounds like you lost gears 3 and 4 - my understanding is that this is a common failure in the 4L60 transmission. It happened to me at 149k miles but I was able to get home in 2nd gear.

Pretty sure it has nothing to do with the instrument cluster. Most likely you will need to have your trans rebuilt.

BTW if you're in the Denver area I'd recommend High Country Transmissions on Alameda. They did mine last year and it's been great ever since. Reasonable cost, too, IMO ($2000.)

 

[CO-Tahoe]

Yeah, I was thinking that if there is an in line short maybe coming off the VSS or in the harness line it may cause some weird crap elsewhere. I am no mechanic by any means but I was just wondering and hoping it's something much simpler than a 2k transmission build.
I'm hopeful that the shift solenoids will fix the shifting issue but we will see tomorrow. I think that I should see dome shavings or worse in my pan when I pull it if the transmission is shot. Fingers Crossed
On a side note, I see your in Englewood, I'm in Littleton so I guess I should say " Howdy Neighbor!".

 

[01ssreda4]

Trans uses speed as one of the main shift parameters, if the PCM isnt receiving this signal wacky things could happen. ABS is its own independent system and does not interact with normal driving.

 

[CO-Tahoe]

Well I changed the 2 shift selinoids and it was still not shifting so I started checking other things. Turns out that there was a wire that for some reason was not plugged in at the harness sitting on top of the t-case. I found the female end that was on the harness and bingo!! I fixed several issues. Service light off. Transmission shifts like Amish butter. Speedometer started working. I'm as happy as a pig in mud
Transmission fluid was clean without any shavings or a lot of friction gunk.
Still have an issue with both the fuel gauge and the voltmeter but Im going to dig into those deeper tomorrow. I pulled the cluster but found out that there isn't much to do with it. Just a circuit board pretty much back there. I cleaned up the connections but it didn't help. I'm still thinking that it may be a faulty ground or something similar. Worst case I'll stick in some after market gauges and call it good.
I did put a meter on the alternator output as well as the battery and it shows 14V while at Idle and 12V when not running. At least I know the pegged gauge is the issue and it's not over charging.

 

[Rocket Man]

Congrats on that trans fix, seems you lucked out there. As for the cluster, the stepper motors are known to go out. You can order new ones and solder them in yourself pretty cheap. YouTube has videos on how to. There are also several places on EBay that will rebuild your cluster as well. You can still drive without a cluster while you wait to have it fixed, they have 1-2 day turnarounds.

 

[shreksbrother]

Congrats on that trans fix, seems you lucked out there. As for the cluster, the stepper motors are known to go out. You can order new ones and solder them in yourself pretty cheap. YouTube has videos on how to. There are also several places on EBay that will rebuild your cluster as well. You can still drive without a cluster while you wait to have it fixed, they have 1-2 day turnarounds.

Piggybacking off that suggestion, also check Craigslist. I found a guy that came to my house, pulled the cluster, COMPLETELY rebuilt it (I had several bad gauges, bulbs out, and shift indicator didn't work), and cleaned it. It looked like a brand new cluster was installed. For $100 it was completely worth it to me.