GM 8.1 owners???

[6.2Diesel]

Ive been on the search for a decent tow rig for a while. I already have a nissan titan but its not fitting the bill for dragging 8000+ lbs over the mountains to moab/rubicon/st george. I have been in many diesels, fords, chevys, dodges. they all are the same, each having their own quirks during certain years.
Im starting to think for the little use im going to actually use it why not drop half the amount and get a GM 8.1, the only drawback is fuel consumption, but it far out weighs a larger truck payment.
Anyway, anybody have one of these 8.1s suburbans, trucks, MDTs that have feedback on how they liked or disliked.
Right now i have a lead on a chevy 2500HD 8.1 allison tranny with 83000 miles for 9000, seems like you get a ton of truck for little money.

 

[thefirstzukman]

My little brother has one just like what you are looking at. He says it it a monster in every way, including fuel consumption. If he puts his 27' Fifth wheel behind it and his Rhino and a couple quads behind that, he gets about 6 MPG. Totally unloaded it will get around 9-11 on the freeway.

All that being said, he really likes the truck. He has had a couple 2500Hd trucks with 6.0 engines and he said there is no comparing them.

 

[Jesser04]

I have 07 classic 8.1 with exhaust and intake. Great truck but doesn't get 10 mpg. Other than the fuel mileage and oil consumption I love it. You're welcome to come drive it if you'd like.

 

[6.2Diesel]

Are these Allison or 4l80e trans in the trucks you have? I've heard Allison's are amazing but I'm sure replacement costs are up there too. As for the 8.1 Is there Anything I should know to look out for, bad years, bad parts, parts that fail?

 

[Jesser04]

I believe all trucks with the 8.1 had the allison in them. I don't think twice about the tranny but I only have 60k on my truck. Only problem is the oil consumption like I mentioned above it will use a quart and a half every oil change.

 

[TurboMinivan]

Oh, hai! 8.1L Suburban checking in:

I absolutely, completely love this vehicle for towing my Jeep. As pictured, my load is right at 6000 pounds. When towing this load, I get +/- 10.5 mpg depending on my exact road speed. If I stick to 65 MPH, I will get 11 mpg while towing. If I step it up to 75 MPH (because that's how fast Brett insists we go) while cruising across Nevada in July with the A/C blasting, I'll get 9.9 mpg. My Suburban has 4.10 gears (giving it a 12,000 pound tow rating) and is entirely stock except for a mild muffler upgrade. I bought it with 219,500 miles; it now has 226,500 miles. I am so happy with how it performs, if it blew up tomorrow I would run right out and buy another one to replace it.

The 8.1L pickups got the (5-spd) Allison transmission, but the 8.1L Suburbans (and Avalanches) got a beefed up version of the 4L80E (4-spd). The torque output is such that the engine doesn't care how many gears are behind it--it just pulls. My 4.10s and stock tires mean 65 MPH is spinning about 2300 rpm. I can stay in 4th gear & overdrive on most mild and moderate hills while towing at that speed; if it does downshift, 3rd gear in lockup puts me at 3000 rpm at that same 65 MPH. This relatively low revving is why I don't burn more gasoline than smaller engines do while pulling similar loads. If you're gonna get 10.5 mpg while towing your Jeep, I'd much rather do it with an unstressed big block rather than a small block 6.0L, 5.3L, or even a 32v Ford 5.4L.

If you're like me and you don't tow every week of the year, it makes sense to go with a gasoline engine rather than the added expense of a diesel. That's why I chose what I did. I did hesitate briefly at the thought of the 8.1L, but numerous people here and elsewhere all told me to go for it because I would love how well it worked. They were all correct, and I'm very glad I listened.

 

[Brad J]

I've heard Allison's are amazing but I'm sure replacement costs are up there too.

I drove a Duramax Van with an Allison transmission at my last job. The trans went out at 250k & was about $3k to get it replaced. I was expecting more than that for parts & labor.

 

[Maverick]

I thought I'd see a Dempsey post in here. Yup, what he said.

 

[Jesser04]

My 07 has a 6speed allison I'm not sure if that's only year or not though. When I'm pulling usually 75 I leave it in drive if I come to a good hill I put it in manual mode and drop it to 4th and slow to 65. I will hold that on most hills pulling my boat or camp trailer. The trucks do not return the mileage the suburbans Avalanches do because of the allison.

 

[TurboMinivan]

I leave it in drive if I come to a good hill I put it in manual mode and drop it to 4th and slow to 65.

I always leave the trans in Drive and I engage tow/haul mode. Well, I do sometimes manually downshift when coming down long, steep hills. When towing uphill, I always let the transmission do its own thing.

The trucks do not return the mileage the suburbans Avalanches do because of the allison.

I always figured the extra cog in the Allison would result in at least equal fuel economy for the pickups, allowing them to overcome their aerodynamic drawback compared to the Suburban... though I have no idea what the actual top gear ratio is in the Allison (or even the 4L80E for that matter). And in case anyone reading along is curious, the Suburbans and Avalanches did not get the Allison because it won't fit in their transmission tunnel.

 

[mbryson]

....or even a 32v Ford 5.4L.

If you're like me and you don't tow every week of the year, it makes sense to go with a gasoline engine rather than the added expense of a diesel. That's why I chose what I did. I did hesitate briefly at the thought of the 8.1L, but numerous people here and elsewhere all told me to go for it because I would love how well it worked. They were all correct, and I'm very glad I listened.

I was quite impressed with the 8.1L on that trip. I wasn't overly thrilled with the 5.4L but it did a LOT better than I expected. With the right trans, I think that 32v 5.4L will tow pretty well. I do agree that for the occasional tow (say once a month or less?), a gasser is totally the way to go. I have a Ford V10 and the aforementioned 32v 5.4L. I think the 8.1L is a better choice than both of those but I wouldn't eliminate the F*rds if you run across a solid deal. I believe the Ford V10 with good gearing could hang decently with the 8.1L but I'd still give the edge to the 8.1L.

 

[BoostedRNR]

My buddy had a 02 8.1 truck with the 6 speed manual in it, and that thing rocked! He was pulling 12-14 mpg's in town and I never seen it drop below 10 on our dune trips. I know the manuals are extremely rare, but if you can find one I would jump all over it.

 

[6.2Diesel]

Should I be scared of high mileage? I'm seeing a few trucks with over 200k on them. I read a post on pirate that the guy had 460 ish k miles, I'm sure it's all about how it's maintained. I'm going to drive some Friday, any shops in the Ogden area that people would recommend to look through the truck?

 

[NYCEGUY01]

My buddy had a 02 8.1 truck with the 6 speed manual in it, and that thing rocked! He was pulling 12-14 mpg's in town and I never seen it drop below 10 on our dune trips. I know the manuals are extremely rare, but if you can find one I would jump all over it.

This.

My 01 has the 8.1 and the 6 speed manual.
Tows as good as any of my old Stock Cummins trucks.

My girlfriend driving it with only a quad in the back got 13-14 MPG this year.
When I drive it empty it gets 9...lol

Pulling my 24' Enclosed loaded down it also gets 9...

It has been a great cheap truck. Plastic floors and manual windows... The perfect tow rig/beater, at least for me..

 

[mbryson]

My buddy had a 02 8.1 truck with the 6 speed manual in it, and that thing rocked! He was pulling 12-14 mpg's in town and I never seen it drop below 10 on our dune trips. I know the manuals are extremely rare, but if you can find one I would jump all over it.

I'd LOVE that truck!!!

 

[TurboMinivan]

Should I be scared of high mileage? I'm seeing a few trucks with over 200k on them.

As I said above, mine has 226,000 miles and runs great. Yes, you should look it over carefully and check for evidence of maintenance... but high miles should not scare you away. This is a rugged, over-built engine which was designed to run at a steady 4000 rpm for days on end (according to my Chevy-loving co-worker who knows the design history of the Vortec 8100).

 

[6.2Diesel]

Im going to go test out a suburban with 124k, 2500hd single cab with 83K and a dually 4 door with 211K all three are the same price, Let the best running one win!

 

[TurboMinivan]

Let the best running one win!

In general, I'd say this is the best course of action but with one twist: make sure your winner has the 4.10 axle ratio (look for code sticker in glove box) as well as the factory HD tow package (look for a trans fluid temp gauge).