Chevy 8.1L - School Me

Mac5005 said:
Change the fluids in everything, filters in everything.

Just check and prep everything as if you were going to drive cross country with it next week.

Then you have a good starting point, and have a chance to look everything over while doing so.

My truck would wear out the rear brake pads 2x faster than the fronts.

Auxiliary bigger trans cooler is a good idea.

My truck did not like a k&n filter due to oil getting on maf.

Get a wix hd paper filter. 2x tall pleated filter.

Change fluid out of brake Master’s as well.

Check hydroboost for weeping p/s fluid.
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That's the kind of info I'm looking for! Thanks
 
They have a bad rap on the crank sensors as well... one bud was prepared to swap his out and found it disconnected at the plug.
My brothers (@Tater '02 2500HD <100k) had some goofy non-typical symptoms (occasional miss, etc) that went away after he swapped his out.

As said, will pull a mountain, but can't pass a gas station
 
Not sure if it's the same transmission cooler that my Duramax powered HD has, but it was totally worth the upgrade. It was a bolt in affair albeit a little spendy.

The Allison spin on filters are only like 8 bucks. I strongly suggest using them. Clean the magnet too, of course. No need to replace the internal "filter" unless you have to drop the pan or you just feel like it. A spin on and drain plug job takes about 7.5 qts. Should set you back about 100 bucks for 2 gallons of TranSynd and a filter.

Also, AFE makes a nice drop in synthetic dry flow air filter if you want to go that route. Just wash it with warm water and soap, let it dry, and keep trucking.
 
My understanding is both the 6.0 and 8.1 trucks share the same exhaust and air filter systems which is more than sufficient on both.

I only run Wix air and oil filters.
 
Be very careful cleaning the throttle body if it’s drive by wire. It’s not difficult to screw them up and they aren’t cheap.

If you go to Napa yo get wix air filter, there is option for the hd one which has taller pleats than regular 5.3/6.0 and std 8.1.
 
Glad you got the teuck. We have a 6500 box truck at work with an 8.1 and the Allison. It's been virtually problem free for the 10yrs we've had it. I've taken it several hours away grossing 26k and never had an issue with power. My uncle had the exact same truck with a CAT diesel and it was a DOG compared to the 8.1. The only problem we have ever had with it was the gas pedal went out (drive by wire) I was about 3hrs from home when it started to go. Truck would run fine for 15 mins or so then go into limp mode. It would throw a code and at first I would unhook the battery for a few mind and run another 15 mins. That got real old so I bought a cheap scanner at an auto parts store and clear the code and keep rolling. Only problem we've ever had with the Allison is that it has some sort of internal leak with reverse. You put it in reverse and it won't go until you hit X000 rpm. It bucks one time then you feather the gas to keep it moving. It feels like you dumped a clutch if you aren't careful. It started doing that about 5yrs ago. It never got worse so we just left it alone! :lol:
 
awheelterd said:
Glad you got the teuck. We have a 6500 box truck at work with an 8.1 and the Allison. It's been virtually problem free for the 10yrs we've had it. I've taken it several hours away grossing 26k and never had an issue with power. My uncle had the exact same truck with a CAT diesel and it was a DOG compared to the 8.1. The only problem we have ever had with it was the gas pedal went out (drive by wire) I was about 3hrs from home when it started to go. Truck would run fine for 15 mins or so then go into limp mode. It would throw a code and at first I would unhook the battery for a few mind and run another 15 mins. That got real old so I bought a cheap scanner at an auto parts store and clear the code and keep rolling. Only problem we've ever had with the Allison is that it has some sort of internal leak with reverse. You put it in reverse and it won't go until you hit X000 rpm. It bucks one time then you feather the gas to keep it moving. It feels like you dumped a clutch if you aren't careful. It started doing that about 5yrs ago. It never got worse so we just left it alone! :lol:
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add brake fluid to trans.. swells seals.
 
Im following this, I just took a trip from Benson to Black Mountain to pick up a new work truck. 05 Flatbed 3500 with the 8.1. I had the ac fixed, complete service with all new filters. Mine has a manifold gasket leak on the passenger side. Looking to get that fixed now.
 
I’m gonna convince him to tow to Harlan with it in 3 weeks, then he can give y’all an update :D
 
So I picked up the truck and have put about 600 miles on it now including a test tow. This thing is great! I do have one question for the Chevy guys...

Last night we drove the truck to get dinner. I had the blower motor turned off (at position 0) and the AC and recirculate buttons off (lights weren't on). I noticed that the vents were cold and with the windows down, they were blowing cold air. When we got home, I left the truck running and checked to see if the AC compressor was running. Sure enough it was. No matter how I arranged the control module (switches, fan speed, temp) the AC compressor was still running. Anyone know how to fix this? It's really not a problem when it's hot out but I foresee it being an issue once winter comes. As a note, I had it set to blow out of the top vents the entire time, not defrost as I know the AC compressor will run for defrost.
 
That may be the control module is bad. I think I have one laying around I can dig out and give to you, but some of the lights are burnt out which is why I replaced it.

Pull the dash bezel and pull out the controls and unplug them to see if the compressor cuts off.

As you may have seen in my tow rig thread, I am having AC issues myself!
 
Between me and @adamk and our trucks, this week will be heading to Harlan with very close to 1 million miles between the two of us!
 
For anyone following along or for future reference, I solved the AC compressor issue.

Turns out the relay went bad leaving it in the closed position. The cause of the relay going was that it was installed backwards. The 4 pin relays that Chevy uses are not poka-yoked and can be installed in two different orientations. When the relay was always closed, the LP and HP switches weren't functional so it caused the system to freeze up on the LP side and caused the compressor to blow off the high pressure relief valve thus losing freon and oil.

A new relay, installed correctly, fixed the issue. Freon/oil was replaced and now all is working well.
 
Also, I've got about 1100 miles of seat time with this thing now and I absolutely love it. It still has plenty of power, the brakes are decent (there's some pulsing that I need to figure out), and the ride quality is impressive for a truck with over 400k miles. MPGs aren't as bad as I thought they would be but I also drive 95% highway which helps. I put new speakers in it since only one was working. I'm also on the hunt for a camper shell. I've come across a few that are in decent shape and decently priced (read as "cheap")

1st Tank: 12.3 mpg
2nd Tank: 12.13 mpg
3rd Tank: 13.43 mpg
 
adamk said:
Also, I've got about 1100 miles of seat time with this thing now and I absolutely love it. It still has plenty of power, the brakes are decent (there's some pulsing that I need to figure out), and the ride quality is impressive for a truck with over 400k miles. MPGs aren't as bad as I thought they would be but I also drive 95% highway which helps. I put new speakers in it since only one was working. I'm also on the hunt for a camper shell. I've come across a few that are in decent shape and decently priced (read as "cheap")

1st Tank: 12.3 mpg
2nd Tank: 12.13 mpg
3rd Tank: 13.43 mpg
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Those are about the same mpg as my F150.
 
If you throw rotors and pads all the way around it, the PowerStops work quite well.

The absolute BEST brake upgrade though is a 2011 Duramax hydroboost. Bolts in and firms the pedal up immensely. You may or may not have to file the back of the pushrod where it meets the brake light switch. I didn't, but others have needed to.
 
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