1998 Crew Cab SB SAS 4L80E issues

[Roger]

Hey guys,

Just recently finished a frame up build of a 1998 k2500 chevrolet crew cab shortbox with the 5.7 and 4L80E transmission, Dana 60 rear and Dana 44 front

Used the cab, engine and transmission from a 1998 GMC 3500 4x4, but switched to the NP208 transfer case, im not sure what case was mated to it originally.

I have two connectors that i have taken pictures of that I have no idea where they are supposed to connect to, one connector is on the REAR o2 harness, and the other is connector to the transfer case rear connector.

I have a CEL caused by the P1345 Code, no other codes, the truck will not shift into overdrive.. I have reverse, first second and third, but no OD.

Any ideas? I appreciate the help

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[Roger]

Let me know if there is any other information I can provide, or any pictures. The stock transmission cooler lines were removed and replaced with AN fittings and -6 line, the correct fittings were used to for the 1998 transmission cooler connections.

I am able to physically select Reverse, neutral, overdrive and third, no second or third are available, the linkage was replaced, could this be a fault collumn shifter?

 

[Roger]

It looks like the old transfer case was the Borg Warner 4401, the case i put in was an np208.

 

[outalne94z71]

that t-case wire is for the electric clutch in the borg warner case, the 208 would not use that

 

[outalne94z71]

Let me know if there is any other information I can provide, or any pictures. The stock transmission cooler lines were removed and replaced with AN fittings and -6 line, the correct fittings were used to for the 1998 transmission cooler connections.

I am able to physically select Reverse, neutral, overdrive and third, no second or third are available, the linkage was replaced, could this be a fault collumn shifter?

what did you do about sealing the cooling circuit , the factory fitting in the later 4l80e have a long end to them to fit inside the cooling circuit in the trans, any line fitting without that would cause it to leak internally

 

[DRAGGIN95]

This is more than likely not your problem but anyway, I bought a 96 1 ton with a 4L80E that OD was supposedly out in, well in my initial checkover after I bought it I was using my live data scanner and at normal operating temp, the ecm was showing a temp of -40 degrees on the engine, so I started checking around and found the engine coolant temp sensor in the intake had one pin broken in it, so I replaced it and I had working OD and no more issues.

 

[Roger]

what did you do about sealing the cooling circuit , the factory fitting in the later 4l80e have a long end to them to fit inside the cooling circuit in the trans, any line fitting without that would cause it to leak internally

A correct AN fitting with the long neck was used for the transmission, I remember it being a special order pain in the ass

 

[bggrnchvy]

It's a 241 not a 208. 208's don't have a VSS, they have a mchanical cable.

The o2 harness connector, it's a square connector?

You have a single catalytic converter in the truck? I believe that the plug for the secon post cat o2 sensor.

 

[blacked94blazer]

the 1345 code is a camshaft sensor to crankshaft sensor correlation code meaning that the base timing on the engine is off, needs to be at o deg tdc + or - 1 deg, you need a scan tool to look at the cmp offset and set it at 0, check all the fuses for the cam and crank sensors, and check the connectors for loose connections, as far as the no 4th gear in the 4l80 it could be an overdrive housing just behind the oil pump i have seen these leak and cause no 4th gear, also i have seen the bolt that holds the housing crack the housing or the bolt itself crack causing a pressure loss, as always check the fluid level and condition. hope this helps!

 

[Roger]

It's a 241 not a 208. 208's don't have a VSS, they have a mchanical cable.

The o2 harness connector, it's a square connector?

You have a single catalytic converter in the truck? I believe that the plug for the secon post cat o2 sensor.

Thank you for the help, that is definitely what that connector is for now that i looked at it again