AlanF

At present my 1999 will not start out in 1st if I leave it in drive. I have to go from Neutral directly into 1st to start out in first. I think this is what is called "limp mode". The transmission will not shift into overdrive, nor will the torque converter lock up. I do have a mystery switch installed and that also will not lock up the TC. A few months ago I had an intermittent issue where the trans would not shift out of 1st when in drive. It lasted about 2 days and then went away.
Not sure if any of this is relevant, but will throw this in as well, my left turn indicator is on fast cycle. A mechanic I took it too tried to track it down but was unable to source issue. I also lost the steering wheel switches that control cruise and the stereo system, switches just gave up the ghost and fell apart.
OD light on dash turns on and off when switched with button on gear selector, but makes no difference to shifting as it isn't shifting right anyway.
I just finished replacing the governor pressure and solenoid in the valve body, but this has not solved the problem. Rats.
I just tried with a code reader, but couldn't get it to work, I have had problems in past with code readers not making a good connection at the OBD11 port, will try again tomorrow to see what codes come up.
I do have the factory manual, but am hoping someone could point me in the right direction to trouble shoot and solve this issue please.
Thanks,
Alan

AlanF

I did manage to get my scan tool to connect, and it shows no codes stored?! It seems like the transmission speed sensor would be next to be replaced, but I don't just want to throw parts at it. I have a pressure gauge that I could rig up for measuring governor pressure. What kind of hose would be appropriate for this application? I do believe the test ports are 1/8NPT, so rigging up a functioning gauge set up should be straightforward.
Alan

leeboy

AlanF

Spent a bit more time on the issue today. I replaced the transmission speed sensor in the tail housing a few weeks ago, no change. I tested gov pressure this morning and as soon as it was shifted to drive, the pressure immediately went to 75psi. I started some electrical checking, and noted I did not have power at my transmission relay. I looked further and found the 10amp transmission fuse was blown. I replaced the fuse (I used a 5amp as it was the spare I had) and I got power back to the relay base. I was hopeful that it was as simple as that. Started it up and put it in drive, first gear start! Yay! Go for a test drive...... Booo, back to no upshift out of first gear. Back to the workshop, thought I would check gov pressure again. This time when I put it in drive, pressure remained at zero. I was not able to check gov pressure with road speed as my OTC pressure gauge only has a 6' hose and I have to run it through the open passenger door to read it from the drivers seat. Any suggestions?
Alan

AlanF

Update, I went for a drive and truck goes into first when gear selector is in Drive. Governor pressure does not move off zero. I checked for continuity between transmission speed sensor (brand new) and pcm checks ok. I did notice when underneath that I do not have a spring on the throttle cable lever where it connects to the transmission! I did fashion up a spring and wire to keep the lever full forward at start up, but this also made to difference, no rise in gov pressure and no upshift. Could an out of adjustment throttle cable cause a no rise in gov pressure?
I also checked the cable between the transmission plug pin4 (gov press signal) and pcm - conductivity and pin 5 gov pressure solenoid controll and pcm - also conductivity.
Alan