Allison P0872

scrambler

New member
Aug 30, 2012
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Hi , newbie here. Please be gentle if any info left out.
Got a 2002 LB7 with the Allison 1000. It is setting code P0872 (E shift valve) in the TCM. I have checked the wiring from the TCM to the transmission, all checked out good. On advise from others, the Valve body ( came with internal harness and PSM) was replaced with a GM/Delco unit from a local parts supplier (not dealer). Also installed a new white NSBU switch. The internal and external filters were replaced, and new fluid was added (about 9 quarts). It is doing the same thing that it was before all this work was performed, which is starts and idles fine, but when placed in D, after about 3 seconds, shifts violently hard into default 3rd gear and sets p0700 in ECM, P0872 in TCM. Has anyone ever had this problem before? Could I have gotten a bad new valve body? Could it be a pump pressure problem? or something internal mechanical failure of the transmission. All is stock, and we got 160,000 on the odometer. Thanks for ANY and all answers or assistance. Thank You!
 

scrambler

New member
Aug 30, 2012
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Do you think it is possible for the brand new valve body to have the E valve stuck? Just asking, not questioning. I do not have that much experience with valve bodies. New valve body was complete unit, upper and lower halves with PSM and harness attached.
 

Mike L.

Got Sheep?
Staff member
Vendor/Sponsor
Aug 12, 2006
15,686
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Fullerton CA
Do you think it is possible for the brand new valve body to have the E valve stuck? Just asking, not questioning. I do not have that much experience with valve bodies. New valve body was complete unit, upper and lower halves with PSM and harness attached.

If there was any debris in the fluid or if you had dirty hands, or if you over tightened it, yes. This fricken valve will stick if you look at it crosseyed.
 

chevyburnout1

Fixing it till it breaks
Aug 25, 2008
2,368
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Berthoud, CO
Had the same issue when I first built my trans. Everything was spotless and torqued and it still stuck. Mike got it fixed up though!