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View Full Version : Chevy 2500 HD with a 8.1 /auto



Bahner tunnel
12-12-2003, 06:28 PM
Does anyone have a Chevy 2500HD with a 8.1 and a auto trans ? How do you like it ? Does it tow well? Tell me what you think about it so far. I'm looking to buy a used 2001 2500HD crew cab and I want to se how it works with a load. Thanks for your replies in advance.

Starloans
12-12-2003, 06:38 PM
I have a 03 GMC 2500HD with 8.1, 4x4 and I love it. 9 mpg whether you are towing or not. :D I would have to say the gas mileage in the only downfall. Takes about 20 acres or real estate to turn it around. :D No compact parking spots.
http://www.***boat.com/image_center/data/500/438Truck0005-med.jpg

fourspeednup
12-12-2003, 06:47 PM
My bro-in-law has an '02. Love the truck, I'm gonna buy it when he's ready to go the dually route. The 496 is a gas and oil hog. Expect around 10-12 mpg and 1 quart of oil per thousand. Tows great, actually rides very well even unloaded. If the one you're looking at has the allison tranny, go for it.:cool:

Maxey
12-13-2003, 05:29 PM
I have a 03' Extended Cab 2500 HD. I
knew that the mileage would not be good. This truck is absolutely great!!
I average 11.5 MPG, and have gone as
high as 13.5 MPG. BE CAREFUL, you will find yourself towing your boat @ 75MPH and not even feeling it. Oil consumption has been "nil".
Maxey

Flying Tiger
12-14-2003, 08:20 AM
http://www.***boat.com/image_center/data/500/939PB260057-med.JPG
I love mine.
I tow a 9000lb slide out trailer+ two 350 lb quads and ya barely feel it back there.
Not towing the mileage is 13+ MPG.
Towing the boat about 10MPG.
Oil consumption is maybe 1 quart between changes if I'm doing a lot of heavy, hot weather towing and kicking it in the ass.
No problems, and I do all the owners manual suggested maintenance.
Power galore on any grade gas..

anxious
12-14-2003, 02:50 PM
no complaints at all. have the stock 4.10 on 42's and get 9 around town. alison tranny is by the far the best route to go. no oil consumption here

fourspeednup
12-14-2003, 03:20 PM
Good to hear not too many others have the oil consumption prob. There was a service bulletin concerning the PCV system venting not only excess gas but oil too especially in hot weather (Phoenix). Chevy dealer in town scheduled to fix this one soon.:cool:
Allison tranny is great too. Solid:D

MKE - POWER
12-15-2003, 05:10 PM
I have an '02 Chevy 2500HD 4x4 Crew cab long bed, with 8.1l and Allison/3.73R.
The truck tows like nobody's business. Burned up the stock tires
quickly.
The motor is very loud; knocks excessively and used oil(qt/1500m)
so I bitched to Gm with the help of the Service Manager.
They said all the noise was not a problem and oil use is standard
to 1 qt/1000 mi.
GM gave me an extended 6yr/72k mi warranty no cost.
Changed to Valvoline 20-50 and now uses a qt/2500mi.
I run a K&N FIPK, Hypertech programming, and Flowmaster Catback.
I do love this truck, but 8-11mpg is a drag.I now have 48,000 mi.
The ride is great, empty or loaded; seems to ride better at @80
with a couple of dirtbikes passing Fords uphill...

fourspeednup
12-15-2003, 07:43 PM
Knocking was in another service bulletin, people were putting shit gas in.:yuk:

DogHouse
12-15-2003, 08:12 PM
I had an 01 GMC 8.1/Alli crew cab short bed 4x4. Very nice truck, quiet, comfortable, and fast. Big block had a very satisfying howl. Far as I'm concerned, the biggest downfall was the much acclaimed Allison tranny... Towed well for the most part but on the steep stuff would drop to third then second gear and spin 4k+ to maintain speed. Tranny was quirky to say the least. With a load, it would drop from fifth to third on even a slight hill, completely bypassing fourth, which should have been a good pulling gear with all that torque. Unfortunately the tranny would not let the motor pull and would downshift way too soon. It also would really bang into gear hard after I'd back out of the driveway and then shift into drive, especially in winter, but only after the truck had sit overnight. One time it got completely lost and refused to go anywhere until I shifted it a couple of times. Also had wierd clunks when coming to a stop and then letting off the brake to get going again. I had the truck into the dealer many many times while still under warranty and the answer was always the same... "it's normal" Yeah, right. F'n GM.
Motor had a slight lifter tick or knock at idle. Definitely used more oil than normal, but not 1 qt/kmile as others have reported. 10-11 mpg normal around town, 11-12 highway unloaded, 8-9 towing. 26 gal tank sucked big time. Stock torque management software also sucked when getting squirrely from a stoplight. Diablosports tuner really woke the thing up and made it haul ass, also improved mileage about a point and got rid of most of the torque management crap.
Now I drive a Dodge Cummins diesel with a manual tranny. This truck doesn't do anything wierd, doesn't try to think for me or outsmart me, and I'm very happy with it! Nice warranty too.
-brian

Dr. Eagle
12-15-2003, 08:34 PM
Originally posted by MKE - POWER
I have an '02 Chevy 2500HD 4x4 Crew cab long bed, with 8.1l and Allison/3.73R.
The truck tows like nobody's business. Burned up the stock tires
quickly.
The motor is very loud; knocks excessively and used oil(qt/1500m)
so I bitched to Gm with the help of the Service Manager.
They said all the noise was not a problem and oil use is standard
to 1 qt/1000 mi.
GM gave me an extended 6yr/72k mi warranty no cost.
Changed to Valvoline 20-50 and now uses a qt/2500mi.
I run a K&N FIPK, Hypertech programming, and Flowmaster Catback.
I do love this truck, but 8-11mpg is a drag.I now have 48,000 mi.
The ride is great, empty or loaded; seems to ride better at @80
with a couple of dirtbikes passing Fords uphill...
While I don't have a truck, my 3/4 ton suburban with the 8.1L engine pulls awesome. All of the chevy big blocks i have ever had have used oil. My burb uses about 1 qt every 3K miles. My 502s in my boat used 1 qt every 10 hours or so. I understand it has to do with the Forged pistions.
If you keep your foot out of the throttle, you will get better mileage than with the small block. It has so much torque that you don't need much gas pedal to go with traffic.
I get about 12-13 mpg around town and 14 on the highway at 80mph on the cruise, 15 mpg at 70.
If I jackrabbit start I get 8 or 9 around town. Towing my Ultra (about 4500 pounds) I get about 12 on the highway. Towing my Eliminator at 9660 pounds before I sold it I got 9mpg.

Starloans
12-15-2003, 09:04 PM
I got a video tape with my GMC that explained all the noises and quirks about the tranny. I know there are a lot of dodge and ford people out there but under a constant load, max pulling, etc, the allison is probably going to be hard to beat. I agree it does make noises and act quirky. But when I hook up, I'm confident I can get my boat to the lake. Isn't allison the same company that makes trannys for semis and bulldozers? I may be mistaken. Maybe I dreamed that. :confused:
Other than the noises and clunks and such has anyone had mechanical prob with the allison?
BIG BLOCK GM. They use oil. Fact of life. Boats, cars, trucks. I can't remember if I read the article here or in a magazine but basically GM has different pistons and rings which are "looser" as compared to the "tight" Fords which robs the horsepower. Everyone wants HP so when you buy something with GM power get yourself a case of oil :D I did. I would rather have the power. Evidently, Merc would too. :cool: I used to have a ford exploder. 5.0 liter. Put 80,000 miles on it. Never added oil. Never.
I drove my 28 with the HP525 to Catalina Thanksgiving weekend. Pretty much upper end of the RPM range there and back. Has 25 hours on it. Had to add a quart when I got back. No prob. :D

Dr. Eagle
12-15-2003, 10:35 PM
Yes, Allison is the same company that does that. They also make Gas Turbines for helicopters. The company was started in the early 1900s making turbo superchargers. GM bought them and they also made engines (the engines used in the P 38, 39 and 40, A-36 which was an early P-51 for example). Not the greatest high altitude performance, but adequate.

Flying Tiger
12-17-2003, 04:58 AM
http://www.***boat.com/image_center/data/500/939PB260057-med.JPG
It's a little diesel like sounding starting up cold. but quiets on warm up. Other than that, I feel none of the quirks some have mentioned.
3.73 rear screws. The tow/haul mode probably is best above a 8000lbs load back there. It's really great with downhill engine brakeing when towing (jakebrakeing???).
A driveline clunk appeared at about 40K, went away when I put on new rear shocks. Old OEM shocks completely worn out.
One of the things I love about it is 65MPH at 1900RPM; super quiet. (the Goodriches occasionally sing a little) Power to pass with a heavy load up most grades.

Quality Time
12-17-2003, 10:47 AM
Let's see if this works.
2003 2500HD, 8.1, Auto, 4X4, 4.10's. and love it! The tranny shifts exactly when it should (like driving a manual). The truck has never met a gas station it didn't like :D

Lightning
12-17-2003, 01:12 PM
If I was looking at this truck I would seriously consider the diesel. i have a '04 crew cab 4x4 with the Duramax. The gas mileage is 18 mpg and gas costs about $0.30 less a gallon. As far as the overall truck is concerned, I have not complaints about it at all. Tow's like a dream, does not burn any oil.

arjetfxr
12-18-2003, 10:12 PM
I've got a 01 2500HD crew cab with the 8.1/Allison combo for sale. This is the best truck I have ever owned, but if your worried about gas milage its not for you. Mine is black with tan leather interior, completely loaded, in great shape, but has 62,000 miles. Asking $23,000, e-mail me for more info.

UnionJack
12-19-2003, 08:37 PM
I have an 04 duramax on 40's w/ 425hp and 750lb, 14mpg.... don't do wait and save up for a deisel... and one is better then gas

wannajetboat
12-23-2003, 11:26 AM
I have an 01, with the exception of the oil consumption, a quart and a half every 3000 miles I have zero complaints. Like many other posters have mentioned if you are worried about gass mileage than stay away from the 8.1L, it will give your bank account a workout. I installed the K&N FIPK and a Flowmaster muffler, gives it a little mor HP's and now it doesn't sound like a can opener running down the road. I highly suggest the truck, it does it's job and is comfortable while doing it. :cool:

Starloans
12-23-2003, 12:26 PM
Hey Wanna,
Here is San Diego I have a guy who wants about $1700 smackers for K&N, Cat back Flowmaster and Chip.
When you added yours did you notice a change in MPG and can you really tell a difference when you step on the gas?
Thanks

wannajetboat
12-24-2003, 10:54 AM
Hey Wanna,
Here is San Diego I have a guy who wants about $1700 smackers for K&N, Cat back Flowmaster and Chip.
When you added yours did you notice a change in MPG and can you really tell a difference when you step on the gas?
Thanks
Mr. Loans,
Deffinately didn't gain any gas mileage with the additions was getting about 10 before I forked out the cash and am getting about 10 now, I did notice the extra power, couldn't tell you how many extra HP's I am getting but the guys that I purchased the Flowmaster and K&N from told me that between the two of them I should see anywhere from 20 and 30 extra HP. I am considering the chip, I want to find out what it will do for me before I fork out more $$$. FYI, I paid about $525.00 for the two additions.
wanna out.:cool:

Bahner tunnel
12-24-2003, 09:40 PM
Thanks for your replies. I ended up getting the truck last friday. So far I really like it. I rides nice ( for a 3/4 ton 4x4) and has good power. It has the 8.1/ Allison 5 speed auto . I like the chevys' " fit and finish" and overall good looks. I plan on lifting it soon .

Starloans
12-24-2003, 10:24 PM
Originally posted by wannajetboat
Hey Wanna,
Here is San Diego I have a guy who wants about $1700 smackers for K&N, Cat back Flowmaster and Chip.
When you added yours did you notice a change in MPG and can you really tell a difference when you step on the gas?
Thanks
Mr. Loans,
Deffinately didn't gain any gas mileage with the additions was getting about 10 before I forked out the cash and am getting about 10 now, I did notice the extra power, couldn't tell you how many extra HP's I am getting but the guys that I purchased the Flowmaster and K&N from told me that between the two of them I should see anywhere from 20 and 30 extra HP. I am considering the chip, I want to find out what it will do for me before I fork out more $$$. FYI, I paid about $525.00 for the two additions.
wanna out.:cool:
Thanks WannaJet.
Did you get the cat back exhaust or just the flowmaster muffler?
I'm looking at the cat back system ($500+ labor) and other goodies.

wannajetboat
12-31-2003, 10:45 AM
Mr Loans,
I just had the flowmaster muffler installed. With just the muffler installed it has a definite rumble to it now. Just an FYI, just returned from Tahoe, got about 12.5 per gallon, not great but when passing the big rigs that extra power is sure nice.
Wannajetboat out. :cool:

Starloans
12-31-2003, 11:35 AM
Hey WannaJet,
Thanks for the info. If I could hit 12 mpg it would be awesome. Maybe I just have a big ass FOOT!
Thanks again.
Dave