The older trucks definitely stand the test of time way better.

The square bodies and the GMT400 trucks are the most solid trucks GM has ever built in my opinion. And they will be around forever.

The GMT800s are also pretty solid and reliable trucks.

Once you get to the GMT900s, the quality dropped WAY off. I'm not a fan of the 900 trucks at all.

GM stepped up their game big time for the k2xx trucks as far as build quality and materials go.

Biggest downfall of the older trucks is they lack capability compared to the new ones. The frames are way stronger, suspension much beefier, and motors way more powerful in the new compared to old.

What happened with you flex fuel? Alcohol composition sensor drifted high?

 

What happened with you flex fuel? Alcohol composition sensor drifted high?

Yes. Before I knew what was happening, I changed the fuel pump, like all GMT400 trucks I had before the GMT900. That's one of the issues I forgot about. I did have to change the fuel pump in the 98. Never did in the 99.

Anyway, the fuel pump change didn't fix the hard start issue, so started searching the forums. Yes, was consistently reading high regardless of what fuel I used. After a fuel trim and ethanol reset at the dealer that cost me 140.00, I've been anal about only filling up with a warm engine and driving at least 10 miles while monitoring the ethanol content. I hate it, but I've been tolerating it because of the cost of used trucks right now.

And because I live in NC, I'm part of the current LC9 class action lawsuit. Would be nice to get a buyback. I had planned on keeping it long enough to see how the lawsuit turned out.

 

@jmbrad How old are your O2 sensors and are the GM OE?

You think you're going to get anything meaningful from that lawsuit? You'll be lucky to get a check for $4.31 while the vultures put their kids through college and vacation in Europe.

 

O2 sensors, I assume, are original. They pulse like they're supposed to when I was diagnosing the issue earlier. I am aware the fuel composition sensor is virtual and based off O2 calculations.

I have been part of class action suits before, and yes typically only the "liars" win. However, I have also gotten significant awards too. MFS lawsuit I got over 800.00 from. This LC9 suit only includes a few "bellwether" states, of which NC is one. I'm not holding my breath by any means, but I was planning on keeping the truck until the outcome at least.

My dad passed away in March and I had 3 trucks until 2 weeks ago. Sold his 77 Chevy K10 and 08 Nissan frontier. I didn't expect the transmission in my truck to crap out on me so soon. Story of my life.

 

Only 69k miles.

A trusted shop local to me swears by the 4L60E 4-speed. His rebuild price is $2,850 with warranty. Since you do not know the history, maybe trusting the truck rather than the previous owner?

I've got the same GMT902. A contractor tried talking me into towing far over the 4700 lb rating, telling me "The truck can take it". Yeah, I said, no way. You never know. Someone may have hooked 6,000 lbs to the truck for a while and wore out a few critical components. The transmission itself should easily last 200k-300k, even 500k+.

 

Am I the only one that feels this way?............. I drove a 98 for 13 years with no issues. 250,000 miles, not a single problem except water pump, starter, and wear items. ..... 1999 for another 7 years. No issue except the brakes. Lousy brakes on the regular half tons. The 98 was a heavy half ton with the 3/4 ton rear end. If I could clone that truck I would do it until I die..................Am I alone in my sentiment?

Brutha, you are not alone in that sentiment. Just prior to COVID, I spent about 6 months shopping for a brand new (or low-mileage, gently used) GMC or Silverado 1500 4WD. I am a picky buyer, I was looking for that 'special' truck that really grabbed me, something I could appreciate every little detail in. And I have to say, I didn't find it, I was disappointed in many different things........... not gonna try to list them here.

Anyway, I ended up keeping my '03 Silverado, still driving her and still love her. 128k miles now and runs like new. I've got Bluetooth, a great stereo, TPMS, a nice interior, great ride quality, and she's very easy to fix, plus she costs me nothing now (except repairs). And if she gets a little chip or ding, it's no big deal.... worry-free.

Like you, I also had a '98 K1500, with 5.7L and it was a terrific truck, with shitty brakes. I should have upgraded the wheels and brakes, but never did. But man, that truck ran great. But my fav is this '03 I now have. I would keep this truck til I die, if it would last. And I think it might, except for the rust, that's gonna kill it. If/when I have to replace her, I might look for another of this gen, from rust-free zone, with low miles.

 

So far estimates range from 3800.00 - 4504.00 for either a rebuild with upgrades or, the highest, a remanufactured from unknown source. Shop wouldn't tell me.

I'm friends with one shop owner about an hour away, he was also the middle price, 3900.00. I guess that's the best option for me. He replaces the computer and valve body regardless of condition just on the safe side and said he uses borgWarner parts.

Sounds good? Opinions?

Closed the week of the 4th, can start on it the following week.

 

I like the deal with your buddy at $3900. Maybe he can tweak the tranny shifts a little. I had a 2011 Chevy Avalanche that I bought new, and the shifting was just horrible. It was set from the factory to shift early in all gears (to save gas, I guess), and it would ALWAYS be in a gear that was too high for the speed, except for highway, so it was lugging all the time. This, coupled with the atrocious AFM, made for the worst-driving vehicle I had ever owned, LOL. I had it re-tuned (both the engine & trans, with AFM turned off), with all the shift points raised, and it was MUUUUCCCH better and more pleasant to drive.

 

I like the deal with your buddy at $3900

Just looked it up. My quote dates from August 5th 2021 . . .

 

Taking my truck to the transmission shop tomorrow. Hopefully not as bad as they expect.

 

Keep us posted.

 

Got the truck back yesterday. Unfortunately I'm not happy with the way it drives. Feels like it's still too soft in the shifts like it was when I bought it, but before the slipping started.

They changed out all the valves, the computer and the torque converter. All parts are supposedly longer lasting. They also put in a larger transmission cooler. Total because of the larger cooler was $4494.00

I'm sick to my stomach over it.

I've been reading up a lot on the 6L80E and it really doesn't matter what you do to it it's still drives like crap. It will never shift like a 4L80E no matter what you do to it.

I'm ready to just give up on trucks all together. At this point I want to sell it and get an old GMT400 2500 Suburban or Yukon.

 

You can GREATLY improve the way the 6L80 feels and shifts with a good tune. I love mine. Maybe get with Lew...

DiabLew Tune - Custom Tuning for GM Vehicles - DiabloSport inTune 2030, Diablo inTune 8245 Platinum, DiabloSport Trinity, inTune, DiabloSport Trinity 9245 Platinum, Custom Tuning by 06MonteSS, custom GM tuning

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www.diablocustomtune.com

 

Yeah, this ^^^^^^^^^^ trannies are extremely tunable nowadays. They respond wonderfully to a good tune. I bought a brand new 2011 Avalanche with 6L80E & 5.3L... it shifted horribly, was sluggish all the time (especially with the AFM), it would shift into high gear at ~30mph, and then refuse to downshift until you REALLY pressed on the go-pedal. It was very disappointing, and I too was "sick to my stomach" that I bought this new vehicle that I now (after about 2 days of ownership) hated driving, haha.

Luckily, I have a terrific GM expert tuner in my area, so I took the truck to him, and he tuned the engine and trans, and it drove beautifully after that. It took him as long to tune the trans as it did the engine. I was in the vehicle the whole time, and I was amazed at all the tuning options for the trans................

Thank you for the encouragement. I've exchanged emails with Lew before. He said when I got the transmission fixed to get back with him.

I really don't want to throw any more money at it. Cut my losses and get out.

 

Yeah, this ^^^^^^^^^^ trannies are extremely tunable nowadays. They respond wonderfully to a good tune. I bought a brand new 2011 Avalanche with 6L80E & 5.3L... it shifted horribly, was sluggish all the time (especially with the AFM), it would shift into high gear at ~30mph, and then refuse to downshift until you REALLY pressed on the go-pedal. It was very disappointing, and I too was "sick to my stomach" that I bought this new vehicle that I now (after about 2 days of ownership) hated driving, haha.

Luckily, I have a terrific GM expert tuner in my area, so I took the truck to him, and he tuned the engine and trans, and it drove beautifully after that. It took him as long to tune the trans as it did the engine. I was in the vehicle the whole time, and I was amazed at all the tuning options for the trans................

 

Oh yes, forgot to mention they also changed out the rear main seal even though it wasn't leaking yet.

 

You will thank them for that later on. You always change the rear main while you are in there.

 

What temperature does your 6L80 run unloaded normal driving?

Before the rebuild I never saw it over 144. Now it's 153?????

 

Mine runs around 150 most of the time. Sometimes around 180 when plowing snow.

 

Are there any other transmissions that will work in my 2011 besides the 6L80/90?

Maybe an Allison? I'm sure it would be some sort of a custom solution?

 

You don't want an allison behind your motor. It'll suck power like you wouldn't believe and also be major overkill.

 

So are there any other options?

 

No, maybe a 4L80 but that would be ass behind a 5.3

6L80s and 90s are good transmission. You need to monitor the fluid and what not but they are not bad transmissions if built properly.

 

My experience has poisoned me. No more 6L80/90 for me. Fool me once, shame on you. Fool me twice, shame on me.

 

Really the only other sorta decent option is a built 4l80e. But personally, do a mild build with a good torque converter on a 6l80/6l90 and your set. They are good transmissions when you put a good converter in front of them

 

One other thing to keep in mind is that it takes 150 miles or so for the TCM to adapt and re-learn and settle-in on things like shift feel, etc. Give it a little time before you throw in the towel.

 

Just wanted to give another update on the transmission.

I took the truck back to the shop and they drove it for a few days. They said there's nothing wrong with it. He owns a Tahoe with the same setup and he says it drives better than his own. I guess I'm just used to the 4 speed feel. The 6L80E just feels disconnected to me.

 

Custom trans/engine tune is your next step on that if you want to try anything else. You already heard the feedback here, you would probably have a tough time finding someone who said a custom tune made there trans shift worse, or that it wasn't worth it.

Otherwise, as you said, cut your losses and go back to older rigs.

 

Went camping last weekend. At 54 years old, we're still tenting it. Bed loaded down with maybe 600 lbs of camping gear it did fine. Had to execute one emergency stop and if I was in the GMT 400, I would have had to hit the emergency lane. I praised the 2011 stopping distance and my wife patted the dashboard and said she couldn't believe I offered it praise for once. Maybe I found it's one redeeming quality, safety.

 

Yes and no.. hah. I have owned 3 GMT400s.

I had a 94 K2500, glad I sold that one. I didn't like the Pre-Vortec motors and OBD1 headaches.
I also had a 95 4-door Tahoe 4x4 - as much as I did love the setup of that, it was still OBD1 and that 95 TBI motor has too many bugs.
I DO wish I still had my 97 K1500 Z71 though.. that thing was enjoyable.

 

How STUPID is chevy ????

I just went to the chrysler jeep dodge dealer to get my jeep serviced the other day...One of the salesman pulled up a dodge Ram 1500 "CLASSIC" to road test with a client. Acoording to the salesman the doge ram CLASSIC is the old body style -you can still order in 2019 !! Great news if you don't...

www.silveradosierra.com

this classic will continue to get ~ regular service maintenance *

 

You think you're going to get anything meaningful from that lawsuit? You'll be lucky to get a check for $4.31 while the vultures put their kids through college and vacation in Europe.

 

I'm not holding my breath over it. I realize most class action suits only make the lawyers richer. I wasn't born yesterday.

However, I have received as much as 1400.00 in class action lawsuits. That might be chump change for most people, but it's a lot of money to me.

This particular case is already decided, and has yet to be successfully appealed. I'm a patient man, we shall see.