more about the DO NOT SHIFT light problem..

[trey]

twice since we've owned the bus, the "DO NOT SHIFT" light has come on and the bus wouldnt get any speed and wouldnt shift out of drive.. I checked the fluid, it was low, i filled it and we drove off fine with it working. that was like a month and a half ago and we've had no problems since. until yesturday I started it up and the buttons you push to shift R-N-D-2 by the seat, well the red lights wer'nt lit up and when i pushed them nothing would happen.. so i checked the transmission fluid and it looked like it might have been a little low so i filled it, turned off and restarted the bus. The shifting light kindof came on. the red light was blinking a little bit and the DO NOT SHIFT light was on.When the lights we a little brighter and it let me shift, it shifted into drive and i thought it was alright. I drove it to the tire place with the very resricted speed and it not shifting out of drive. The Drive light was lit up but it sounded like it was running in 1st or 2nd. (i pulled over to try to put in neutral but it wouldnt shift) i turned the bus off for the guys to fix the tire and when i turned it back on it shifted normal. does any of this mess make sense to anybody?
trey 

i forgot to mention, in neutral the bus feels fine. when i push the drive button the bus does this chug jolt thing every second or two we're sitting still.. sometimes when driving, after reaching about 50mph, the entire bus will shutter violently.. forgot to say that earlier.. thanks again

[NJT 5573]

Trey, you didn't say anything about clearing the codes, so lets clear the codes. Hold test switch to transmission side and with the bus running with park brake ON shift N,R,N,R,N,R. put trans into N, hold switch to trans side and reread codes. If they are not gone, repeat the N,R, deal until no lites blink with the switch held down on the check trans side. If you don't have a tranny full of shiney stuff, try some Lucas Oil trans additive. It greatly improved the shifting smoothness on my 748 ATEC. The vibration is bad, if its inside the tranny, its on its death bed. Maybe the vibration is a Ujoint between the tranny and the differential. Do you have a bulge on any of your tires, that could cause some serious vibration. If you don't have the shiney stuff in your tranny fluid a service may be due. One of the most important things to do is remove the pan and replace the O ring on the pickup tube. If that O ring is worn, the pump will suck air instead of tranny fluid and they don't shift smooth with an air/fluid mix

[NJT 5573]

Trey, before you delete the codes, write them down and I'll look them up. It will flash 2 times followed by 1 time, and that is 21, 4 flashes and 5 flashes is 45 etc. To read the codes, hold the test switch on the trans side and they will start flashing out, smallest number first and continue to loop so you can reread if needed.

[Chris 85 RTS]

Maybe he has a power problem or a ground problem to the computer.  Did you remount or rewire anything in this area?

[Sammy]

Sounds like an intermittent speed sensor problem - very common.
Flash the code and post it like NJT has already mentioned. We'll help you from that point.
Sammy