LB7/Allison

inkjunkie

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Sep 14, 2022
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Bit long winded, may want to get something to drink.
Bought the truck in 07. Grenaded the trans. Friend owns a shop, his builder went thru it replacing anything that was questionable. Only thing that was factory was the convertor...which I broke. Got a TCS triple disc billet convertor. Left the desert and moved to the Inland Northwest.
For several years now when the ambient temperature is below freezing I have 2 choices...let the truck warm up until the trans temp is above 35 or get a very harsh first shift. Every time I went to see my friend fixing it just never happened. He would dump the fluid, replace the filters and then remember about the slam shift. The builder my buddy had the last time I was there told me that when he owned a shop in Oregon he seen quite a few early trucks with sticky valve body valves.
Fast forward a bit and the truck started acting a bit weird when taking off from a stop. Felt like you had a trailer behind you with the electric brakes cranked up.
This past summer I made several trips from the Spokane area to Yakima, I am the track camera guy at Renegade. Noticed that my Edge display had the trans temp over 230*...it never ran that hot even pulling 12k pounds thru the desert. Hit the trans sump with a touchless thermometer, it read 155*. Buddy said I needed to replace the pressure switch. Did so. And hell broke loose. P0700 and P0875. Replaced the NSBU. Checked all the grounds. Checked damn near every wire I found on the schematic that is trans related. All is good.
Truck has been done for 3 weeks now. Have 3 trips remaining on my camera gig. I am disabled, renting a car is putting a hurting on the bank. Need to get this thing up and running.
Buddy suggested I drop the pan again. Pull the valve body and check the valves to make sure they are moving freely. He also told me that he had picked me up a set of TransGo Valves. He blew his trans up a while back and they went into his trans prior to him selling the truck. He told me that these valves being a bit sticky could be causing the cold issues as well.
Any thought/suggestions/comments would be greatly appreciated.
 

inkjunkie

New member
Sep 14, 2022
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Pulled the plug off the trans. Have not checked it with a meter but if I were a gambling man I would say I found the problem, one of the wires does not feel right. Gave it a bit of a tug...the insulation started stretching. The connector is part number 12186609. Does not look like this connector is meant to be taken apart. Looked on GM Parts, they have one with leads on it. Guess I will be doing some soldering. Going to check it with a meter when I go back outside.
 

Bdsankey

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Feb 1, 2018
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Neenah, Wisconsin
I am guessing you’re stating the issue is in the connector that plugs into the back of the trans on the chassis side, is that correct?

A broken wire, of any kind, can/will certainly cause issues. I have not had to replace one but you certainly should be able to pull that pin out, strip/recrimp a new pin onto the wire, and put it back into the connector OR you can replace the entire connector at that point.
 
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inkjunkie

New member
Sep 14, 2022
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I am guessing you’re stating the issue is in the connector that plugs into the back of the trans on the chassis side, is that correct?

A broken wire, of any kind, can/will certainly cause issues. I have not had to replace one but you certainly should be able to pull that pin out, strip/recrimp a new pin onto the wire, and put it back into the connector OR you can replace the entire connector at that point.
Yes, the wire was on the connector that is on the harness in the truck. The trans internal harness was seeping fluid. I ordered a new connector with pigtails on it.
 
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Bdsankey

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Feb 1, 2018
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Neenah, Wisconsin
Yes, the wire was on the connector that is on the harness in the truck. The trans internal harness was seeping fluid. I ordered a new connector with pigtails on it.
If the internal harness is leaking at the pass through IMO just replace the harness. They’re not extremely expensive and it’s a pretty easy job to do.
 

inkjunkie

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Sep 14, 2022
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Found 2 more broken wires on the connector going into the internal harness, wasn't the problem. The 4 pin connector on the NSBU has a slice in one of the wires (under the black retainer piece on the back). The other 3 wires look suspicious.
 

inkjunkie

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Sep 14, 2022
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Replaced the 4 pin connector...and the code continues. After I got the old connector out I manipulated the wires, one of them was definitely broken. So despite a total of 6 failed/failing wires being repaired p0875 carrys on. Next chance I get I am going to pull the harness off of the trans plug and closely inspect them. This is getting old.