Thinking of upgrading from a 7.4 to a 8.1 Gasser

Be prepared to deal with the AutoRide magnetic shocks, they will be shot at that mileage. $250 each to replace or otherwise bypass the system and go with aftermarket shocks.

Spark plugs don't go to 100k and also don't need a professional to replace, they are some of the easiest plugs to change. If the vehicle is a from a salt belt winter state, check the brake lines for rust.

Tow capacity is 12k with the 4.10 axle, 10,500 with the 3.73.

Road trip and find one down south or out west that is NOT rusty. I hate rust!

zell66 wrote:
thanks all...as far as spending $$$ at the pump my 7.4 now gets 8 to 10 pulling and a 55 gal tank....so still around $200 to fill it up. lol they want $4995 for it so I think I will have a good mechanic take a peak at it and see what he says.

That's a great deal...yeah, have someone check it out, that would be the smart thing to do. Let us know it works for you should you decide to get it...don't get me wrong, I really liked my 8.1.

thanks all...as far as spending $$$ at the pump my 7.4 now gets 8 to 10 pulling and a 55 gal tank....so still around $200 to fill it up. lol they want $4995 for it so I think I will have a good mechanic take a peak at it and see what he says.

I owned an 01' 2500HD with the 8.1/496 CID Vortec..SON, it was an awesome engine, though it didn't meet a filling station it didn't like...Heck, I'd recommend the 8.1...it was a towing animal....just be prepared to spend money at the pumps........but, it did run well...sounded good too:)

I love my 8.1 and have put 56K miles on it in 7 years. It does want a quart of oil every 3K miles or so. My brother, who rebuilds his owns engines and such and who has an 8.1 Yukon, tells me that having the spark plugs replaced by a professional at 100K miles is a MUST.

Am in a similar situation...would love to go the newer/better 8.1L and 4L85E, but
for me, bigger bang for my buck is to rebuild my 7.4L. The 4L80E doesn't need it,
but what the heck...when I do the 7.4L...going to rebuild the 4L80E (think the
parts for the 4L85E works in mine...but will check that out closer later)

Noodle how much to rebuild vs buying a newer TV

What diff ratio in your Sub?

That newer XL has more miles than my 5 year older 1996. Make sure to have
the drive train checked out by a 'good' mechanic

The 8.1L's oil consumption has been attributed to both SS rings taking longer
to seat (40K miles or so) and misting that is then drawn in via the intake
manifold

To me, my GMT400 seems bigger inside than both GMT800's and GMT900's. I'm 6 foot
and about 180 lbs

You do get better brakes on the GMT800 (four wheel disc...though that era had
flaking of the rear disc...fixed with new suppliers)

Do change out the receiver with a traditional design. About $150-$200 plus about
1 hours labor

Thats the way I'd go. Getting harder to find ones with lower mileage; I've been looking.

About the only complaint I've ever read from owners of the 8.1L is their appetite for gasoline (not a big deal at 6000 miles per year), and engine oil.

Sounds like the big powerful gasser fits your situation perfectly.

The Allison was the auto behind the 8.1L in the pick ups, but in the GM SUVs its the 4L80E or the 4L85E.