# 2000 2500 Ext cab 6.0 sluggish



## Arc Burn (Oct 21, 2002)

OK fellas,2000 Chevy 3/4 ton 8600 gvw(not HD) with the 6.0 and auto trans with 60k miles.I'm not impressed at all with this engine especially after getting in my 98' with the 350 vortec for the first time in a few months.the older truck will run circles around the 6.0 and the 350 has 100k on it,what gives?The 98' had a new tranny at 80k and the 6.0 doesn't seem to shift as well,could i be looking at tranny probs here?The 2 trucks are litterally night and day,i can't believe it,anything obvious we should look at first here?


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## wyldman (Jan 18, 2001)

I know the 6.0L is no powerhouse.The newer trucks have gotten bigger,heavier,and have more accessory loads.Also gearing and tire size have a big influence on power.The 350 Vortec was a really strong motor.

Have you checked the basics,like plugs,air filter,throttle body,etc.Or maybe a plugged cat ?


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## John DiMartino (Jan 22, 2000)

Arc,have you kept up on the fuel filter/air filter maintenance on the 6.0? Id start with a new fuel filter/or a pressure test,the fuel pump could be getting weak,(not likely though).Also the cat convertor could be plugging up,restricting flow.One guy I knew had low power on his,turned out he bent his tailpipe in a snow bank backing up,pinched it almost shut,it would idle and cruise,but had no power,and a cool whistle . If all that checks out,it may be time to get the ignition system,and the ecm/pcm checked out.


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## Arc Burn (Oct 21, 2002)

Air and fuel filters are new,i never gave much thought to the plugs because everything today is supposedly good for 100k ,I'll check those this week along with the cat.The fuel pump does change its pitch every now and then from high to low(you guys know that chevy fuel pump whine!)
The truck has no obvious probs untill you floor it and just doesn't have the get up and go i would like,mind you i'm not lookin to smoke Johnny D here or anything but it's gotta have more than that.
Now i'm not the mechanic that you 2 boys are but something tells me it's a tranny prob,i just don't know how to check it.

Will check the above first though and keep you posted,thanks


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## Ohiosnow (Sep 20, 2001)

*Arc Burn*

Sluggish 

My 2001 - 6.0 (300-hp)2500HD x-cab 4.10 runs like a raped ape  I can smoke them everytime from a stop if I floor it :waving:

Has it always been sluggish ??????

As for the tranny a buddy of mine had the dealer update the flash for the tranny shift points & it made a big difference in his truck


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## Arc Burn (Oct 21, 2002)

How do i find out what gears i have in the rear?
I bought the truck used at the dealer were i bought the last 3 so for the time i've had it yes,it's always been sluggish.
The more i think about it,i just don't think the tranny shifts right 
If i were to take it to a dealer what should i say,"update the flash" or my tranny seems weak?


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## wyldman (Jan 18, 2001)

To determine the rear axle ratio,you can usually read it right off the axle tag,on one of the cover bolts.If not,count how many turns of the driveshaft are required to get one full wheel revolution,with the wheels off the ground.


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## Arc Burn (Oct 21, 2002)

Just spoke with the local dealer and he says he can reprogram the tranny but it's not likely to change the shift points and it's not likely to do anything because the service light is not on.

He says by my description it sounds like either a fuel filter(new) or pump.It only gets better because now they sell an entire "module" that drops in the tank(everything included) for a mere $500 and it's over $700 for them to do it.

BTW-They want $50 just to check the pump,what do ya say there oh wyldone ?


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## wyldman (Jan 18, 2001)

The newer trucks are very sensitive to fuel pressure,so it could be a pump.$50.00 to check fuel pressure is pretty steep,so shop around.

Try another dealer for the reflash.Tell them your trans isn't shifting right,and they should take care of it.


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## Arc Burn (Oct 21, 2002)

That's it,Chris,clean out a room,i'm movin to Ontario Look out Canada,here I come!Just kiddin
Thanks for the help guys,hopefully it's not a fuel pump.Did that price seem right for the new "module" Chris?


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## wyldman (Jan 18, 2001)

Sounds about right.They are $700-800 here depending on application.

Don't be temped to go aftermarket,as they do not last,and sometimes pressures are a bit low right out of the box.You don't really save that much,and it's not worth the headaches.


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## Arc Burn (Oct 21, 2002)

Next move is gettin the pump checked although there is no stumble or burble or any skip of any kind it's just real doggy,wouldn't low pressure give me some of those symptoms?


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## wyldman (Jan 18, 2001)

As the fuel pump wears,the pressure starts to drop off.If it's only a few PSI,then usually the concern is lack of power.Once the pressure gets to low,then you start to get a lean stumble on tip in,or a rolling idle.

The newer vehicles are so adaptive,that they can mask a bad pump for a while.The only complaint will be a slight loss in power.

Are you sure this isn't a jealousy thing cuz Johnny D is making all kinds of power now ?


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## Arc Burn (Oct 21, 2002)

LOL,No!...I don't think so  
Nah,seriously though even when i got it i had some speculation as to the power but the truck felt so much "smoother" i thought it was just in my head.Like i said the real wake up call was the other day when i drove the 98' with the Vortech,there is simpily no comparison which got me to thinkin somethings wrong and the more i drive it and think about it i don't feel it shifts right.
The only other thing i can mention is at 60k miles i'm not sure the tranny filter has been changed,i've got the filter and fluid but i've also got 400 different welding jobs sitting in the shop,hard to get my own stuff in sometimes 
I think Johnny D could rip me apart if he raced backwards at this point


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## John DiMartino (Jan 22, 2000)

Hey,I could alwasy race you with my 91 GMC,which is reliable,yet lethargicly slow,LOL. I love the truck,but the 350TBI is so sluggish once your above 40 or so,it struggles with any hills at all,LOL. Arc, I think your 6000 should tear the 350 apart. I have friends with both vortec 5700,s from 96-99 and the 5300 Ls1 derived 99-01's. The 5300's easilypull away from the older 5700 in any type of speed contest. Although towing is a different story the 350 Vortec holds its own against the 5300's there.Your 98 could have 4.10 gears,and the 2000 may have 3.73,that alone will be enough to make the 350 feel quicker,and stronger.


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## JCurtis (May 14, 2001)

Ok this was posted in another thread about 6.0's .... Guess I was asleep when I typed it this morning.

Sluggish ???????????? I don't know about that 
I just completed a a three hundred mile trip ( a combination of highway and city driving) I did a quick calculation and came up with a average of 14.25 mpg. I havent done any work to my truck since I bought it a couple of months ago, and I admit I did have it running about 65-70 mph on the highway, so I know that that decreased the mpg a bit.

I don't know about the various comments about the 6.0 being sluggish... I haven't noticed it in my truck. As a matter of fact, I have to take off slow from a stop light/sign because I can actually break the back tires loose on dry pavement and spin them for quite a distance ( even further on wet pavement) if not careful.

I know the tires aren't brand new, but the do have adequate tread, so its not like I'm spinning slicks.

I do think however I may have a bad u joint because every once and awhile I hear a clunk. Gonna get the truck serviced, and have it all checked out for winter. Then It starts getting outfitted for winter. Checking out various plow dealers this week, and will soon have the plow mounted. then I am building a weight box for the bed so that I can retain a sufficent counter weight over the rear axles and still have room for eny equipment/supplies I might need to load into the truck for plowing.


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## Arc Burn (Oct 21, 2002)

I'm gonna check the tags for the gears tomorrow.I also have a few buddys with the 5300 and the 98' will walk them,so at this point it's probably about the gearing in that truck.
I'm not sure i'm ready to race your 91' either,imagine if i lost I'd be the laughing stock of the town!

Hey Jeff,LOL,I read your post in the fuel thread this morning,no prob:waving: Do you know what gears you have in yours by any chance?
John,if this was a gear problem,do you think it would be worth swapping them out?How much $$ am i lookin at? Thanks for the help fellas


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## John DiMartino (Jan 22, 2000)

Jeff, I noticed the same thing as you,ive only driven 3 6.0's,but they all were plenty strong and had what i thought was more than enough power,especially for a base engine. Arc,maybe you have what Vinnie and I call a "crack 5700,and a "slag 6000",LOL. If your 5700 can beat a 5300 in a similar truck,then you defintelty have a strong one,its a keeper.


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## Michael F (Oct 18, 2000)

I have two trucks similiar to your.
1999 k3500 reg cab 454 with 4.10 gears, and a 2002 2500hd ext cab 6.0 with 4.10 gears. The 2500 is faster off the line & tows better. The 454 is rated at 270 hp, the 6.0 is at 300, I'm not sure about torque, I belive the 454 had like 30 more ft/lbs. Like I was geting at if set up the same, your 6.0 should definitly keep up.


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## Arc Burn (Oct 21, 2002)

No tag on the axle,is there a code in the glove box that might give some insight,I did notice i have the snowplow prep code in there the other day.


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## JCurtis (May 14, 2001)

Arc,

I believe I have 3.73's in my truck, I'll dig up the window sheet and double check. I bought this used and the seller was a fanatic about keeping all the paperwork.


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## TravisA (Jul 25, 2003)

> _Originally posted by Arc Burn _
> *OK fellas,2000 Chevy 3/4 ton 8600 gvw(not HD) with the 6.0 and auto trans with 60k miles.I'm not impressed at all with this engine especially after getting in my 98' with the 350 vortec for the first time in a few months.the older truck will run circles around the 6.0 and the 350 has 100k on it,what gives?The 98' had a new tranny at 80k and the 6.0 doesn't seem to shift as well,could i be looking at tranny probs here?The 2 trucks are litterally night and day,i can't believe it,anything obvious we should look at first here? *


Arc my dad had the same thing happen to him. He had a 98 with the 350 vortech sold it and bought a brand new 2000 3/4 ton with the 6.0 He was disappointed in the performance and regretted selling his 98.

His motor seemed to be very noisy also. We think this could be part of the power loss while pulling. It sounded like piston slap and if the computer picked up on this noise it could have been pulling out timing thinking it was knocking. He now has a 99 5.3L truck and loves it.

At my work we have both a 5.3 and 6.0 and to me it feels as if the 5.3 would run circles around the 6.0 and again this motor is noisy at idle.

Travis


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## wyldman (Jan 18, 2001)

I have heard quite a few noisy 5.3 L's,but no 6.0 L's.I was under the impression most of the noisy engines were 5.3L only.GM had some kind of owner goodwill with an extended warranty on them.


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## Ohiosnow (Sep 20, 2001)

*I have both 5.3-Tahoe 4x4 & 6.0- 2500HD*



> I have heard quite a few noisy 5.3 L's,but no 6.0 L's.I was under the impression most of the noisy engines were 5.3L only.


And both are quite & run very strong :waving:


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## TravisA (Jul 25, 2003)

My experience is with my dad's 6.0 and the one at work. Both are 2000 models and both are noisy. The 5.3 is a 02' model and its quieter. The 5.3 seems to have faster straight line performance but doesn't pull as well as the 6.0

When my dad took his 6.0 to the dealer they claimed it was piston slap and would rebuild it with the 02' pistons. He didnt like that idea and sold the truck.

Travis


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## John DiMartino (Jan 22, 2000)

the 5300 trucks will always be quicker,since they are in lighter 1500 series trucks with the 4L60E. The 4L60E has better gearing and is more efficient in power transfer than the 4L80E.The 2500 trucks are 600 lbs heavier than the 1500 at the minimum. The tow test is where the 6.0 shows its torque advantage,its also where the 4L80E shows its advantage too.


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## wyldman (Jan 18, 2001)

Did you ever get it checked out Arc ?


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## Arc Burn (Oct 21, 2002)

I changed the air filter(which needed it) and am about to change the trans fluid and fliter,I'm looking for a local dealer/shop who knows what i'm talking about when i ask to have the trans "flashed",I've spoke to 3 and they don't have a clue how it would help?


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## wyldman (Jan 18, 2001)

It's actually the PCM (powertrain control module) you want to have flashed,or reprogrammed.You may just have to go in complaining about a trans shifting problem,and tell them to do all the updates.Most dealers won't admit about updates,or reflashes unless your actual complaint matches the symptoms which the reflash is supposed to fix.


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## Arc Burn (Oct 21, 2002)

Well i changed the filter and fluid today and will drain it again tomorrow for good measure.The fluid wasn't burnt and wasn't really dirty and the filter i took out was the same CarQuest filter that i put back in so it has been changed at some point.

On another note i spoke to a mechanic at a small shop today who referred a tranny shop about 3/4 hr away who can do the Flash updates,funny but he also said dealerships are picky about running updates umless you can describe exactly what the update should help.Hopefully this month i'll get it in there.


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## wyldman (Jan 18, 2001)

We used to have a list at the dealer,with actual phrases,or complaints the customer MUST mention to get certain work done.I know this definatly applies to some reflashes or updates.Would be nice to know the "exact phrase" you need.


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## Ohiosnow (Sep 20, 2001)

*"Would be nice to know the "exact phrase" you need."*

I asked what he said exactly to the dealer to get the to flash the updates & he said he told them the trany was slow to shift sometimes & it was tempermental when stompimg on the gas :yow!: as to how it would shift. He said the dealer said they had refashed many 2000-2001 trucks & SUV's as there were many complants  & told him it was no big deal :waving: I guess it's the difference between dealers


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## Arc Burn (Oct 21, 2002)

Ohio,thanks,thats exactly how the truck acts,like i mentioned i found a tranny shop with the equipment,just have to get it to them.

Chris,why wouldn't an update be ran on all model/year trucks instead of particular trucks?What i mean is if there's an update listed for 00' Chevy 6.0 with 4L80E trannys,why don't they just flash them all?Why do some dealers make such a big deal over it,it seems second nature when we speak of it here,Can you mess it up?


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## wyldman (Jan 18, 2001)

They can easily kill a PCM if it's flashed incorrectly,or something happens during the upload.The manufacturers figure if your truck is fine,then don't touch it,so no updates for everyone.

Sometimes the updates can create problems in other areas,so they only like to flash the ones that really need it.It is also all about money,as the manufacturer foots the bill for the reflash if it's under warranty.


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## Crazy_Eddie (Mar 31, 2003)

> _Originally posted by Arc Burn _
> *No tag on the axle,is there a code in the glove box that might give some insight,I did notice i have the snowplow prep code in there the other day. *


GU6 = 3.42
GT4 = 3.73
GT5 = 4.10

I would think you'd find eith the GT4 or GT5 in you glove box. If it's not one of those I have a sheet somewhere with all of the RPO codes on it somewhere and dig it up..


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## Little Jay (Dec 12, 2001)

So if the forum is to offer opinions and trouble shoot, this could go on forever! 
Our company has owned all Chevy's for 15 yrs. I have A.D.D. when it comes to trucks so I've put nearly every model through my own personal torture tests.
My feeling is you should dump your non-HD and get a 2500HD.
Your truck, once the problem is corrected (and there is a problem to be sure), should beat any vortec truck, but not by a whole lot (assuming no mods have been done).
I had a '99 2500, classic style, and loved it-350 vortec 4.10 rear. Strong and durable. I then bought a 2000 2500, new style, 6.0, 3.73. It ran well but was not nearly as fast (gears i'm sure). In my kneck of the woods, as I soon discovered, we found a problem with these trucks. I blew out three half shafts on the driver's side, three front diffs, and two transfer cases. This was all covered under warranty, and after the last fix they found that the "factory had set the transfer case to the wrong backlash" which somehow caused all these problems.
In talking with fellow owners of the same truck, I found that many people had similar problems, though most didnt want to take the time to worry about it.
Long story short, I had the dealer buy the truck back from me and bought a 2500hd.
The small horsepower increase is noticable and I do circles around the diesel guys. I load up my 8 ft blade with pro-wings and my 8 ft back blade with the wet snow and can drag it to Mexico: not to mention the summer trailers w/ lawn stuff.
Before your truck develops front end problems, I'd sell it and get a 2500hd with the 6.0.


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## Arc Burn (Oct 21, 2002)

Crazy_Eddie,thanks for the info,turns out i have the 3.73's in the 00',i'll check the 98' tonite.

Little Jay,I've run 3 different 1/2 ton Chevys with IFS ragged and have never had any front end or tranny trouble of any sort and those were only 4L60E trannys,i'm not the least bit afraid of the front ends of the non HD's.


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## John DiMartino (Jan 22, 2000)

Arc,IMO the 4L60E,and 700r4 are tougher plowing trannys than the 4L80E. The 4L80E has a weak reverse gear ,and the gear ratios arent as good for plowing.


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## Arc Burn (Oct 21, 2002)

So John,is a gear swap an order about now That would probably frig with the computer aye?Unless i'm shelling out the dough for another Hypertech programmer


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## John DiMartino (Jan 22, 2000)

Gear swap,heck i was thinking along the thoughts of a Cummins swap , If your 6.0 had the 4.10 it would definelty be quicker.


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