Trans Down Shift for no reason!?

Street sleeper

Street sleeper

Part-Time Puller!!
Joined
Feb 10, 2009
Messages
411
Last night I was pulling 12,500 lbs behind my 96 12v with the Goerend's in it. I was pulling a hill with the TC switch locked and 3/4 throttle at 1650 rpms and 60mph, when for second it wanted to downshift into drive a couple of times. The truck had plenty of power and I have done this same haul before without this happening. So after this happened I flipped my TC swith back to regular and pushed down on the throttle but the TC didn't unlock until I got to the top of the hill and let completely off the throttle and then stepped back into it. Trans temp was at 130 degrees and everything seemed fine. Just wondering if any of you guys could put a little light on this problem I had. Thanks.
 
almost sounds like your TPS, but I mine would only lock and unlock the tc while in O/D not down shift into 3rd. Just a thought.
 
Once in a blue moon, my truck will be running along in overdrive and then downgear into 3rd. For some reason it is the factory O/D off switch or wiring, and it just does it ever so often. I have heard of several people reporting that this happens occasionally with theirs too. Im not sure that is what happened to you, but its a possibility.

Id also suspect the TPS could be causing problems. Mine would downgear into 3rd at times when the TPS was going bad. Usually after I had been running it hard in overdrive for some reason it would downgear to 3rd while I was still running 70mph or so. So that could also be the problem.

Eric
 
Cummins Driver said:
Once in a blue moon, my truck will be running along in overdrive and then downgear into 3rd. For some reason it is the factory O/D off switch or wiring, and it just does it ever so often. I have heard of several people reporting that this happens occasionally with theirs too. Im not sure that is what happened to you, but its a possibility.

Id also suspect the TPS could be causing problems. Mine would downgear into 3rd at times when the TPS was going bad. Usually after I had been running it hard in overdrive for some reason it would downgear to 3rd while I was still running 70mph or so. So that could also be the problem.

Eric
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Mine does this even with the POT in there. once in a great while it will just downshift to 3rd and the o/d off light will be on, on the original o/d off switch. once you push the button for o/d off once the light shuts off and it upshifts fine back to 4th. i'd really like to know how to fix this too.
 
Yeah, mine also does it still with the POT mod. No idea why they do it really. Its just like you said though. The light comes on on the button and everything, so you just hit the button, and it up****s and your on your way again.

Eric
 
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