GM 8.1 liter engine.

95Trooper

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Hey guys, I’m looking at buying a very clean 2001 GMC Yukon 2500 XL next week and wanting some honest opinions on the engine/trans in this body style SUV. I’ve read it’s supposed to be a competitor to the Duramax engine. I have owned several of the 2000-2006 body style Tahoes, Yukons and Suburbans and absolutely love them but they all had the tried and true 5.3 LS engine in them. I’ve read about oil consumption and cold start knock with the 8.1L but that’s about it. Seems to be a very reliable platform. A buddy of mine has a boat with the 8100 and it seems to be a beast! I know MPG will suffer, but it will NOT be a daily driver so not a huge worry. Also, what transmission will be in it? Is it an Allison trans or 4L80/85? I can’t seem to figure that out because everyone says something different.
 

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As far as I know all those Burbs & YukonXLs had 4l85s

They are good strong motors. Just stay on top of oil level
 
Suvs did not get the Allison. I went back and forth on 8.1 or 6.0. The first 3/4 ton suburban I was lined up to go look at was an 8.1 but they decided not to sell. Ended up switching my search to 6.0 just for parts availability and I have a spare lq4...
 
It will be the 4L85E. I had an 02 Suburban 2500 with the 8.1 and I really liked it. To this day I regret selling it but I needed a truck to pull a 5th wheel camper. With 285 sized tires I got about 12mpg and between 8-10 towing.

I did have to keep an eye on the oil level and keep it topped up but wasn't bad.
 
I have an 05 Silverado with the 8.1 and it has 435k on the original motor and trans, as does @adamk who has the identical truck with roughly the same miles, all original as well.

The 8.1 pulls amazing. It’ll pull any load up any hill but it can’t pass a gas station. But I don’t mind.

Always check the oil, it’s very normal to use oil a bit more than you may be used to. If it has low oil pressure at idle, don’t be alarmed. Mine idles at 18-20 once hot, stays around 35-38 at speed. It also has a slight rattle/knock sound at cold start up but goes away in just a few seconds.

Always let it warm up before you tow with it, it’s somewhat common to score a cylinder when people just jump in and take off with a load. I usually let it run a few minutes before just driving it period.

Not sure what the price is but if it’s clean and taken care of, inside and out with not a ton of miles it worth quite a bit more than regular Burbs.
 
Echoing everyone else on the oil consumption. I pretty much always carry 2 quarts in the driver door and it’s fairly consistent that I use 2 quarts between oil changes (3-5k miles).

As @77GreenMachine said, we both have over 400k on original motors and both still pull very well. It’s a solid motor and, when maintenance is kept up, it’ll run for many many miles.

I don’t know much about the 4L85 but it’s older version, 4L80, is a solid trans. Just keep an eye on temps and roll on.
 
@Taters '02 2500HD is likely nearing 100K now... IIRC, aside from an occasional "slight miss" (was crank position sensor), the usual cold piston slap/oil usage/blown exhaust gaskets/single digit MPGs, it's been ridiculously reliable.

I swear I'd have one if every 300K mile plain jane/stripped "work truck" (appearing to have already made 1-2 trips thru the crusher) wasn't $15K...

Funny1: Hauling my Jeep to TN in a convoy of 5-6 other rigs (we're off for a long weekend of wheeling, AC on "swing beef" & tunes on 11 = "_Life_Is_Good!_ mode") and hit Old Fort Mtn., ... about 1/2 way up I sensed something wasn't "right" and started looking around at the usual (trailer tires/Jeep/straps/etc.). He turned down the tunes and we couldn't pinpoint an issue... until I looked over to see it holding a steady 75!:rolleyes: We were passing folks like they were going backwards! Slowed down to 45 after the crest and was within sight of the Swannanoa exit before the rest of the pack caught up! 🤣

Funny2: Once leaving WindRocks years ago, hit a bump (fawker was huge) so bad his radar detector fell off the visor... and the truck went DEAD. We both went wide eyed like "ol' shat?".
After 20 seconds of pontification, the only explanation was when the detector fell, it clipped the ignition and shut it off... 🙄
After getting the detector perched again, started right back up
 
I like my 8.1 suburban
Go for it!
234k on the clock. Runs like a champ.
 
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