8.1L/4L80E swap into 84 Dually

[Rollin_Thunder]

That's actually really cool. Looks good and functional.

 

[89Suburban]

Nice work

 

[1984dually]

Painless wiring problem

Was wiring up the front lights/markers/horn/etc. All wiring is marked as to where they go and wire up good. Problem was after getting it done there was no high beam lights. Cked the headlight switch as well as the dimmer and power was there. Power was going into the fuse panel but not coming out the other side. Pulled out the fuse panel and traced the wiring from the dimmer. Some idiot put the high beam wire in with the wire going to the coolant temp sender when it was built at Painless. Removed it and ran it to the empty hole next to the low beam wire. Repined the engine side to match and now they work. Guys who have that harness from Painless might want to ck that. Only other problem that I need to figure out is the lower brights have some voltage when on dim. Thinking it is getting feedback through the ground side. Very dim but are getting voltage from some where

 

[1984dually]

update

Got the engine running but was plagued with cold cylinders and rough running. First problem was when I turned around the fuel rail I forgot(brain fart) that it is a SPFI system. Don't know how it even started. Was firing what the ecm was thinking was #1 injector on #8 cyl. Turned around the wiring harness and replaced the injectors(figured it was as good as time as any). Still cold on 3 cyl's. Cyl leak test showed less than 10% leakage. Started swapping plug wires and the cold cyl's went with them. runs good Scanner shows no codes and my shop floor shows the increased torque.. Here is a short video of it running. Will make up a list in the next few days of parts involved in the basic swap.

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[Catman3126]

Awesome setup.

 

[bigcountryguy19]

Was wiring up the front lights/markers/horn/etc. All wiring is marked as to where they go and wire up good. Problem was after getting it done there was no high beam lights. Cked the headlight switch as well as the dimmer and power was there. Power was going into the fuse panel but not coming out the other side. Pulled out the fuse panel and traced the wiring from the dimmer. Some idiot put the high beam wire in with the wire going to the coolant temp sender when it was built at Painless. Removed it and ran it to the empty hole next to the low beam wire. Repined the engine side to match and now they work. Guys who have that harness from Painless might want to ck that. Only other problem that I need to figure out is the lower brights have some voltage when on dim. Thinking it is getting feedback through the ground side. Very dim but are getting voltage from some where

I had this problem with my headlights on my 84, turns out that the spades on the lights were corroded, cleaned them and put dialectric grease on them and problem went away.


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[4WDKC]

Did the 4l80e thread ever get created?

 

[74propu]

Interesting, I was planning on manual shift myself so thats no problem. Man, your build thread here just made my life a hell of a lot easier! You know there does not seem to be one definitive swap guide for 4L80Es into squares? I think you may have just fixed that problem...

I have 4l80e transmissions in 2 squares 1 behind a 454 the other behind a 5.7 b/b in a 86 c10 long bed the 5.7 in a 80 c10 short bed

 

[da_raabi]

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[4WDKC]

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I know had to clear the cob webs from it to read all 4 pages but, this is what happens when you search and cant find the answer you're looking for and someone mentions making a post/guide for doing the 4l80e swap into multiple trucks.

 

[az3plus3]

I'm wanting to do this 8.1 swap for a while now. But with a 5 speed allison. Anyone familiar with swapping out transmission with an Allison?

 

[HotRodPC]

I'm wanting to do this 8.1 swap for a while now. But with a 5 speed allison. Anyone familiar with swapping out transmission with an Allison?

Wasn't the 8.1 and Allison combo available in 2500HD and 3500HD trucks in about 2002 or so? It seems in the HD trucks where the 6.0 LS engine was standard, then you got the 4L80-E but if you got the 8.1 or the Duramax you got the Allison with engine braking. Maybe I'm mistaken but it seems to me the 8.1/Allison combo did come OEM in HD trucks which means if you found one of these trucks wrecked, get the engine,trans and wiring for the ECM which should control both the engine and transmission.

 

[Jrgunn5150]

I'm wanting to do this 8.1 swap for a while now. But with a 5 speed allison. Anyone familiar with swapping out transmission with an Allison?

That's the factory transmission on my 02 2500 HD. Pickups got the Allison, SUV's and vans got the 4L80/85E, so all you need is a pickup donor.

 

[HotRodPC]

That's the factory transmission on my 02 2500 HD. Pickups got the Allison, SUV's and vans got the 4L80/85E, so all you need is a pickup donor.

With an 8.1 engine right? In the 2500HD pick up, even the 6.0 got the 4L80-E/4L85-E. IIRC, the only 2 ways to get the Allison was in 2500HD/3500HD Pickups with either 8.1 Gas or Duramax.

 

[Jrgunn5150]

With an 8.1 engine right? In the 2500HD pick up, even the 6.0 got the 4L80-E/4L85-E. IIRC, the only 2 ways to get the Allison was in 2500HD/3500HD Pickups with either 8.1 Gas or Duramax.

Correct, I have an 8.1/Allison combo.