Transplant surgery - Swap 6.0 to 8.1 in '03 2500 Burb

Kneelbeforezod · February 2, 2014

Have a '03 2500 Burb LT Autoride with the 6.0 that will soon be replaced by a lightly used 2013 Yukon XL 2500 for DD and towing the horse trailer.

Been thinking about what to do with the '03. From this thread it looks like the 8.1 could drop right in. However there are other posts from around the net that suggest it is not as simple due lack certain parts for 8.1 like say a wiring harness. As far as I can tell no one has done a 6.0 to 8.1 transplant in a Burb - if they have i could not find a mention. When I ordered my '03 the 8.1 was an option so my feeling is that mounts and suspension should be able to handle it. I don't really care about the mpgs on the 8.1. And i believ the tranny would have be swapped from 4l80e to the 85e.

Any thoughts?

gmtech4 · February 2, 2014

lol,the 8.1 has an Allison behind it ,,,,,crazy idea IMHO ,,,unless ya have tons of $$$$

enjoy the challenge !!!!

zach1990 · February 2, 2014

Your gonna want an Allison with that 8.1. It's gonna thrash any other transmission

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Kneelbeforezod · February 2, 2014

lol,the 8.1 has an Allison behind it ,,,,,crazy idea IMHO ,,,unless ya have tons of $$$$

enjoy the challenge !!!!

Your gonna want an Allison with that 8.1. It's gonna thrash any other transmission Sent from my LG-D800 using Tapatalk

Can you explain why the allison is needed since GM sold the Suburban and Avalanche with a 8.1L with the 85E? The Sub, Avalanche and Yukon xl didnt have room for the ally so it was the 85 that had to be used. Besides the room factor, GM must have figured the 85 was good enough for the 8.1.

gmtech4 · February 2, 2014

i was thinking C/K trucks ,,,i stand corrected ,,,,allison is a far superior transmission

zach1990 · February 2, 2014

Sorry I was unaware of that. With the amount of low end torque that the 8.1 puts out I'd still think about it though

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oldscsc · February 2, 2014

There won't be room under the truck for an Allison unless it receives a sizeable body lift. Regardless, the 4L85 will be sufficient providing the truck is used as intended and not as a hot rod, along with proper fluid and filter maintenance.

sareljr · February 11, 2014

The best route would be to drop a LB7 Duramax in it, you'll have more power and better fuel economy than the 8.1 and I think you can still use the stock 4l80e.