S@ndman
Newbie
Hello all.
New to the network and have a project I am researching. Here is some background. I have a 91 K3500 that has treated me well over the last 9 years. Its only downfall is the 6.2 diesel. Gets fairly good fuel economy but can barely pull the truck alone up any kind of grade. The engine is beyond tired and quickly reaching the point of being totally expired. I scored a complete 2002 2500HD with an 8.1/Allison with 140k miles on the cheap because the body has rusted away to nothing. Actually "idled" it home because it had some wiring damage to the throttle motor, dang mice. Luckily it was down hill most of the way
Repaired the wiring and now have throttle control.
I could go a couple of different ways with this.
Scenario 1- Swap the 8.1 into my truck keeping the 4L80E.
Will the 4L80E shift correctly? I have not figured out if the TCM would work with the 8.1. The ECM from the 8.1 has the TCM integrated. Will this cause issues with the engine running correctly? I am thinking yes but am not certain.
Scenario 2- Swap both the 8.1 and the Allison.
Will the Allison bolt up to what I think is an BW4470 transfer case? Or would the NP261 be able to be stuffed in there as well? I have read somewhere that the Allison is 2.5-3 inches longer than the 4L80E. Will the Allison even fit height wise? I am thinking that will cause issues with driveshaft lengths. Then there is the spline count issues between the BW and the NP261.
I have learned so far:
I need to find the discontinued bracket to relocate the A/C compressor to the top side. I have no ambitions of cutting into any framework as I seen done on the square body swap. My truck is not a square body but I am thinking it would be handy to have the compressor up higher even if there is not a clearance issue.
The 8.1 has bosses that will accept my 6.2 engine mounts. I will be using new replacements. I have some concerns about the height differences between the 2 engines.
Replace the crank position sensor while I have the engine pulled. Be a good time to swap that cam sensors as well as a preventative maintenance item?
The 8.1 will bolt up to my 4L80E and not need a spacer as in the LS applications.
There is a pick up tube under the intake causing oil consumption issues. Is this something that should be addressed with new intake gaskets while I have it out.
I intend on starting a build thread to document and help future folks thinking about this type of swap. Just wondering if there is any advice to be had going into the project. Any input is appreciated.
New to the network and have a project I am researching. Here is some background. I have a 91 K3500 that has treated me well over the last 9 years. Its only downfall is the 6.2 diesel. Gets fairly good fuel economy but can barely pull the truck alone up any kind of grade. The engine is beyond tired and quickly reaching the point of being totally expired. I scored a complete 2002 2500HD with an 8.1/Allison with 140k miles on the cheap because the body has rusted away to nothing. Actually "idled" it home because it had some wiring damage to the throttle motor, dang mice. Luckily it was down hill most of the way
Repaired the wiring and now have throttle control. I could go a couple of different ways with this.
Scenario 1- Swap the 8.1 into my truck keeping the 4L80E.
Will the 4L80E shift correctly? I have not figured out if the TCM would work with the 8.1. The ECM from the 8.1 has the TCM integrated. Will this cause issues with the engine running correctly? I am thinking yes but am not certain.
Scenario 2- Swap both the 8.1 and the Allison.
Will the Allison bolt up to what I think is an BW4470 transfer case? Or would the NP261 be able to be stuffed in there as well? I have read somewhere that the Allison is 2.5-3 inches longer than the 4L80E. Will the Allison even fit height wise? I am thinking that will cause issues with driveshaft lengths. Then there is the spline count issues between the BW and the NP261.
I have learned so far:
I need to find the discontinued bracket to relocate the A/C compressor to the top side. I have no ambitions of cutting into any framework as I seen done on the square body swap. My truck is not a square body but I am thinking it would be handy to have the compressor up higher even if there is not a clearance issue.
The 8.1 has bosses that will accept my 6.2 engine mounts. I will be using new replacements. I have some concerns about the height differences between the 2 engines.
Replace the crank position sensor while I have the engine pulled. Be a good time to swap that cam sensors as well as a preventative maintenance item?
The 8.1 will bolt up to my 4L80E and not need a spacer as in the LS applications.
There is a pick up tube under the intake causing oil consumption issues. Is this something that should be addressed with new intake gaskets while I have it out.
I intend on starting a build thread to document and help future folks thinking about this type of swap. Just wondering if there is any advice to be had going into the project. Any input is appreciated.
