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Discussion Starter · #1 ·
02 LB7/Allison. Trans temp was elevated, at least according to what the Edge display was saying. It was 230*, the sump was 150*. Replaced the pressure switch. Got a code p0875. Started looking, internal harness was drooling into the external harness. Replaced it. Code 0875 again. Did some digging into the trucks harness. Thanks to the above mentioned drooling several wires in the 20 pin connector were wrecked. Replaced them. Never really probed the 4 pin NSBU. One of the wires was cut. Another felt like the strands were broken. NSBU was just replaced, don't know why I did not see this. Got a new 4 pin connector. Code p0875 still. Sitting here thinking about things. I know this almost impossibe to do but what if the reverse signal tube were not inserted (only remember one actually being inserted into the valve body) all the way? Seem to remember the end nearest the solenoids not being in the valve body, this is normal, correct?
 

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When you replaced the NSBU and pressure switch did you use OEM parts or aftermarket?
 

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I would replace those with OEM to rule out aftermarket gremlins
If that doesn't solve it then I would change out the valve body
 
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2007 Klassic CCSB 2500HD. Six-gun w/speedloader, iDash, and EFILive.
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Seen this? P0875....need some help

With as much electrical nonsense as you've seen so far, I'd trace all the wires through the harness. Good bit in the above on how to test the pressure sensor with a meter. Anything MikeL said was gold.
 

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Discussion Starter · #6 · (Edited)
Seen this? P0875....need some help

With as much electrical nonsense as you've seen so far, I'd trace all the wires through the harness. Good bit in the above on how to test the pressure sensor with a meter. Anything MikeL said was gold.
Well....it has no wiring issues at the transmission end. I replaced the 20 pin connector (old one was full of fluid and had what I thought were questionable wires) as well as the 4 pin NSBU connector. The NSBU connector had all 4 wires bent to about 120* coming out of the connector. One of the wires was very flexible. The code persists. I did see the link above. That is my next step. Going to go out and pull the plug on the pan after dinner.
Have a very hard time believing the valve body went belly up. Trans was fine, other then a high fluid temp reading. This all started when I first dropped the pan to replace the pressure switch. Couple of weeks ago I did put the old pressure switch back in and had the code set. Which is why I never tested the new one.
One thing that I am a bit confused on. The reverse tube. It may just be my foggy memory but I am pretty sure that the end furthest from the solenoids is inserted into the VB while the other end is not. From the images I have found it looks like both ends are inserted into the valve body. I very well may be wrong in regards to mine...which is another reason for dropping the pan. I don't see how I could have not put the tube in correctly...
 

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Discussion Starter · #7 ·
Sure enough...some buckethead, that would be me, bent the reverse tube...that is assuming both ends are supposed to be inserted into the valve body. Circuit component Electronic engineering Audio equipment Computer hardware Electrical wiring
 

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Discussion Starter · #8 ·
Well...put it back together and fired it up...cleared the codes...let it run for a few minutes, no CEL.
 

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Discussion Starter · #9 ·
Hit the trans relearn button. Took an hour or so of varying driving to get it to shift normal. Had some odd stuff happen. I backed it out of my yard...about 275' or so. No problem. Was on the way home and stopped on the side of the highway. Clicked it into neutral, no problem. Clicked it into reverse...nada. Blinking light. Drove about 5 miles. Stopped at my gate, no more blinking R light and had reverse. Plugged my laptop in just to take a look. P1093. Set this a while ago...changed all 3 filters and it never happened again until today. Filters only have about 1500 miles on them. Pressure from the lift pump is right where it has always been.
 

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Hit the trans relearn button. Took an hour or so of varying driving to get it to shift normal. Had some odd stuff happen. I backed it out of my yard...about 275' or so. No problem. Was on the way home and stopped on the side of the highway. Clicked it into neutral, no problem. Clicked it into reverse...nada. Blinking light. Drove about 5 miles. Stopped at my gate, no more blinking R light and had reverse. Plugged my laptop in just to take a look. P1093. Set this a while ago...changed all 3 filters and it never happened again until today. Filters only have about 1500 miles on them. Pressure from the lift pump is right where it has always been.
Check your fuel pressure from the lift pump. it should only be around 8-9psi. If it is above then turn it down..

Here is a thread on the 1093 code: Lb7 P1093
 
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