8.1/Allison swap in K3500?

[stutaeng]

Hi guys, I just bought a complete 8.1 engine with a 2wd Allison/ECU out of an '04 2500 HD to swap into my 3500.

My '00 K3500 CCLB currently has a 5.7, and engine and transmission run fine. I was actually looking for an engine for my '99 Silverado ECSB 4.3 to do a swap, but then came across this deal.

I figured I can "re-purpose" the 5.7 into the GMT-800, LOL. I'm currently looking for a 4L80 2wd for the 1500 to mate it.

Anyways, not sure what to do with the Allison. It is a 2wd and 5 speed. I know it doesn't fit under there unless I cut the sheetmetal, and would like to keep the 4x4. Can the Allison be converted to 4x4 like the 4L80? I think I have the BW4401 transfer case. Just seems a lot easier to keep the existing 4L80 transmission/transfer case.

I've never done an engine swap, so it's going to take some time, LOL.

 

[Mikeee404]

I swear I have seen it somewhere that the Allison had an NP261 transfer case. Either way I know there are plenty of 4WD HD trucks using an Allison.

I'll have to watch this post for info because there is someone near me selling an 8.1L for $750, started much higher but apparently it is not a high demand motor because it has been sitting for a few months and the price keeps dropping. I want it for my 99' K1500 Burb but man that would be adding a lot to my project trying to beef up the frame enough to support it. Would love to simply do it just to say "oh you have the 454, that's cute".

 

[1ton-o-fun]

Same reason I'd like to get my hands on a 502 crate engine. Louisville's area code is 502, lol!

 

[HotWheelsBurban]

Hi guys, I just bought a complete 8.1 engine with a 2wd Allison/ECU out of an '04 2500 HD to swap into my 3500.

My '00 K3500 CCLB currently has a 5.7, and engine and transmission run fine. I was actually looking for an engine for my '99 Silverado ECSB 4.3 to do a swap, but then came across this deal.

I figured I can "re-purpose" the 5.7 into the GMT-800, LOL. I'm currently looking for a 4L80 2wd for the 1500 to mate it.

Anyways, not sure what to do with the Allison. It is a 2wd and 5 speed. I know it doesn't fit under there unless I cut the sheetmetal, and would like to keep the 4x4. Can the Allison be converted to 4x4 like the 4L80? I think I have the BW4401 transfer case. Just seems a lot easier to keep the existing 4L80 transmission/transfer case.

I've never done an engine swap, so it's going to take some time, LOL.

I know this is an old thread...but did you ever do this?

 

[stutaeng]

I know this is an old thread...but did you ever do this?

No. I switched idea and considered doing the swap back into a GMT 800 HD instead for ease of plug and play, but I haven't really found a good/cheap/nice donor, LOL.

The 1500 got a 5.3/4L80e, which turned out to be a great combination.

I did discover the Allison transmission requires a tail housing extension swap to convert it to 4x4, although the conversion parts are not cheap. But doesn't require a full year down (which is even more expensive!)

If I decide to do the swap on the GMT400 K3500, it'll be in the Fall, maybe Winter.

 

[BeXtreme]

No. I switched idea and considered doing the swap back into a GMT 800 HD instead for ease of plug and play, but I haven't really found a good/cheap/nice donor, LOL.

The 1500 got a 5.3/4L80e, which turned out to be a great combination.

I did discover the Allison transmission requires a tail housing extension swap to convert it to 4x4, although the conversion parts are not cheap. But doesn't require a full year down (which is even more expensive!)

If I decide to do the swap on the GMT400 K3500, it'll be in the Fall, maybe Winter.

Why not just bolt the 8.1 up to the existing 4L80 in the truck? Do an 0411 swap and run the engine/trans with a stock 8322 OS from a 2001 K2500 8.1/4L80 combo? Or use the P59 ECU that you got with it and just segment swap a 4L80 trans segment in?