Back at it again...

I had my trans rebuilt a few months ago and have had no trouble with it, albiet I haven't taken any long hauls until today.

I had a 120 mile drive today and after about 40 miles the O/D off light came on and the truck downshifted out of overdrive. I immediately pulled over to check the fluid and it looked fine if not a little over-full, which I chalk up to temperature.

I shut it off for maybe 20 seconds, started it back up and it operated normally for 10-15 miles, when it repeated the exact same thing. This time I just kept on' truckin', but at around 50 MPH and after 5-6 miles it returned to normal operation by itself. 10-15 miles later @ 70mph, however, it did it again and this repeated for the entire trip.

I just got home from bringing it to the trans shop that did the rebuild and, get this, they tell me there's an old misfire (cyl 6) code in there (no MIL on!) and that's probably the cause... I can guarentee that code is from when I tuned the truck up and didn't have the cyl 6 wire seated properly, the MIL went off by itself a week later. Then he proceeded to try to sell me a tune-up... Took every bit of me not to sock him in the jaw but I figure I'll clear the computer myself and bring it back when the monitors are reset.

Until then I figure why not try to look into it myself and go back educated?

It seems like it's a classic case of the trans overheating, but I believe there's an idiot light in these trucks and that isn't coming on. Also no other CEL codes present besides the (old) misfire code.

I looked the problem up and found similar circumstances but nothing that exactly matches my experiences (No temp light, no CEL, intermittently fixing itself). Any ideas?

Thnx fellers.

 

Governor pressure sensor, IIRC, has the temp sensor in it. Try to put an IR temp gun by the pan and see what the real (there abouts) is. Maybe try replacing it. I bet they didn't do that when they did the rebuild. Check your invoice, though.

 

Yeah its the governor sensor tripping it. Replace the solenoid and sensor while your in there.

 

I actually replaced the governor pressure sensor and solenoid myself 3 months before they rebuilt it...

 

Then check to see if they re-replaced it. Maybe with an inferior brand or one for the wrong year.

Also check your 8 pin connector going to the trans, maybe it's loose.

 

I suppose that's entirely possible... They seemed like pretty reputable people until the guy tried to tell me a misfire would cause my O/D to shut off. Am I correct thinking that's absurd or is that actually possible?

 

It's not possible, as far as I know.

 

It's absurd.