01 3500HD (gmt400) 8.1L

[tanman_2006]

What are the chances this has a 5 speed Allison?

Found this on an obscure FB for sale page

 

[trouttrooper]

I'd say slim to none. It should have a 7.4 w/ a 4L85E

 

[THEFERMANATOR]

01 is 454/4L85E, 02 was 8.1L/but theres still debate over what trans came in it. They were a 1 year only, so it's not like theres alot of them out there to look at.

 

[tanman_2006]

He says his title is 01 it has a 8100 engine cover and 8.1 on the crossmember

 

[THEFERMANATOR]

It could be a late production 01. The flyers I found said 01 was still 454, 02 was a 8.1l. Just keep in mind they are RARE, so some parts for them may be hard to find.

 

[tanman_2006]

I figure it would have the same engine as a regular 3500 gmt 800. Not sure what rare parts would be involved.

 

[Ed HD]

Basically all the shit that mates it to the truck. The engine itself is probably fine, but engine mounts, exhaust manifolds, fuel lines, etc might be hard to find.

I'd guess it's like a Suburban/Avalanche 8.1, in front of the 4L85E.

 

[tanman_2006]

I really would figure if a Duramax can fit in that chassis then the 8.1l would fit without too many mods. Now I can imagine the wiring harness would be hard to replicate.

 

[THEFERMANATOR]

The base engine is the same as the regular 8.1L in the GMT-800, but like said above there is bound to be some specific parts for the GMT-455 with an 8.1L. I wouldn't let it stop me from getting one, just something to keep in mind with a one of a kind rig.

 

[tanman_2006]

I figure an aftermarket exhaust, intake, and other minor stuff won't be readily available but I find it hard to believe that GM would build a line of parts for a low production/short run set up instead of use parts that are readily available for the platforms.

Might take a bit to figure out what parts they used and where though.

 

[trouttrooper]

wasn't one reason for the deep frame was to handle the allison dimensions? And here i thought I knew it all , I never knew they put from the factory a 8.1 in the gmt400 bodystyle. I guess I would lean towards the 4L85E, but then I was wrong about the engine.................

 

[THEFERMANATOR]

wasn't one reason for the deep frame was to handle the allison dimensions? And here i thought I knew it all , I never knew they put from the factory a 8.1 in the gmt400 bodystyle. I guess I would lean towards the 4L85E, but then I was wrong about the engine.................

They didn't, the 3500HD is a GMT-455. It shares the same body panels for the most part, most of the wiring is similiar, but thats about it. Most everything else about the truck is different from the GMT-400 counterpart. And the 8.1L is RARE to find in the 3500HD as most have never seen one. Theres people who sold these trucks new that had never seen an 8.1L in one. From what I was told, most of the parts are the same as those used in the same year SUBURBAN with an 8.1L, but supposedly teh 3500HD got the ALLISOn whereas the SUBURBAN got the 4L85E.

 

[trouttrooper]

well heck. i better go sit in the corner and start sucking my thumb. apparently i don't know squat about gm pickups

 

[Ed HD]

Oh really, they did get the Allison. Better snatch that one up Tanner!

 

[tanman_2006]

I want to go look at least!