Hey everyone, I own a 1999 Chevy Blazer 4x4 LT. I have over 260,00 miles on it. 1 1/2 years ago I had my Trani rebuilt. Now it is starting to have problems shifting when it is cold ( after a little bit it seems to stop ) this is the same issue I had when I took it in for the rebuild just a bit worse. My question is. With the mileage I have is there any vacuum lines going to the trani that I should check first or does anyone know if I need to look at replacing the shifting sensor on the trani?

My fuel question is. Lately the gauge has been reading wrong. It bounces (or jerks) and never shows under 1/2 tank. I have read it's the float sensor and best to just buy a new fuel pump seeing as you have to get to it anyways to check the connection. Reason why I'm asking is I had a dodge van at one time I had a sensor go bad that made the vehicle cut the fuel on and off. Kinda the same feeling I'm having driving my blazer. and if the fuel pump is going out could it be making me start to stall instead of the trani problem?

Not sure if they could be related if it all make sense on the questions.

Thanks in advance
Steve

 

The 4L60E transmission is fully electronic controlled, no vacuum lines or adjustments to be made. I work at a trans shop, no idea what a "shifting sensor" is. The computer uses vehicle speed, engine load, etc. to determine shift points and quality. The neutral safety switch can also affect shifting if it is telling the computer you are in say D instead of OD. The actual shifting is done with electric solenoid valves, which activate hydraulically controlled valves in the valve body.

The only way to diagnose the trans is to hook a scantool to the truck and retrieve any codes that may be present, and have an experienced mechanic drive it while the problem happens. If you can post the codes here we maybe can give you a few areas to check further.

 

Thank you slimsummers, I saw a diagram of a shift sensor on the side of the trani housing. I wasn't sure if the solenoids are messing up inside. there are no codes coming up on the computer tho I didn't take it to a trani shop yet. trying to avoid that one if at all possible.
Do appreciate the help tho. I was hoping cheap and easy lol. Even tho we know car=expensive & a pain some times

 

The only external component on the trans itself is the neutral safety switch, the vehicle speed sensor is on the transfer case on a 4X4. Best way to test it is to attach a scantool and watch the datastream as you put the shifter in each position. As long as it starts in park and neutral and the computer is seeing the correct gearshift position reported, it is OK.

They do go bad, but are more often damaged if you try to unplug them. Made by Lucas ("The Prince of Darkness", holder of the patent on the short circuit...) they use some sort of hot melt glue to seal the connector cavity and the trans heat melts it, gluing the vehicle harness into it. A 60 watt drop light left next to it for a few minutes softens it up enough to remove the connectors (usually) without damage. At $30 or so you don't want to change it unless you know it's bad.