Chevy Silverado/GMC Sierra's w 8100/Allison

mgdvhman · November 2001

get some paint strainers and after the oil cools down.....strain the oil back into the container.

The paint strainers will catch all the little chunks that are left in the oil....and if left in....can break it down kinda and give it a terrible taste as time goes on..

Peanut oil gets the hottest....transfers less tatse and is supposed to be the best for ya?

Good Luck

- Tim

joe3891 · November 2001

Less air the computer puts in less fuel to keep the ratio 14 to 1,working normal.

n75v111 · November 2001

get better mileage on every vehicle i've driven at the higher flite levels.

2700 mile round trip over Thanksgiving from central IA to VT via Port Huron, Toronto, Cornwall to Burlington w/8100/Ali/3.73 LT excab 4x4 average 12.09 - 70 to 75 for most of the time.
Best leg 13.5 -
Longest leg from Port Huron to Cornwall between fuel stops 493.4 mi mpg 12.18
Love that 38gal Aux. Tank. You DON'T buy gas in Canada!!!

75v

kanton1 · November 2001

I just got off the phone with Chev cust service. I wanted to make sure my truck was built like the dealer said it was. Sure enough, the truck has been built and is in inspection. Does anyone know how long a truck generally stays in production before it is released for transport? Also, any ideas on how long transport would be out to Oregon? Rough estimates or guesses would be appreciated! I'm getting excited, a new crew cab under my Christmas tree!!

Kyle

eric2001 · November 2001

My HD was in inspection for two days before shipping. Best of luck.
-Eric

noobie1 · November 2001

Here's a probable solution to the puzzle of increased economy at higher altitudes:
It's true that as altitude is gained, increasingly smaller gulps of air are in taken which requires ever less amounts of fuel to maintain proper mixture ratio - less fuel consumed. But for any given RPM, because the volume of air/fuel mixture decreases, so does power. And to maintain a constant speed as altitude increases, say 65 MPH, only one thing can result with a normally aspirated engine: opening the throttle, resulting in increased fuel consumption. So, all this seems a practical wash, no loss, no gain. What provided an unwitting hint was 75v's mention of "flight levels". It's well known that most aircraft perform better at higher altitudes, not because of better engine as much as less parasitic drag. In looking into this I found that air is approx. 1/3 less dense at 10,000' than at sea level. 33%!! Although the truck only reached that altitude twice, briefly, most of that leg was from 5 to 8 thousand. It's also significant to note that on the previous leg at lower altitudes the average was 13.2 MPG. So initially, on the Kingman-Durango leg, MPG was probably in the 13's, maybe more, which means to get a 16.1 average it got well beyond that at altitude.
So, it wasn't engine performance that improved, but vehicle performance due to less drag. I can think of no other answer than that except for previous speculation about faulty inputs. Probably wrong.
Ahh, I feel better now. Thanks.

-David

Still looking for that oil filter with an anti-drain back valve. Any help much appreciated.

joe3891 · November 2001

run better an use less fuel because you lean out the mixture and the air is cold an less drag,no manual lean on a truck.
Comparing a truck to an airplane,what a stretch.LOL

noobie1 · November 2001

The comparison was intended only to point out that drag decreases as altitude increases. The question still is, how significant is the decrease in a truck as it relates to fuel consumption? Thanks for your interest.

-David

richcolo · November 2001

that contribute to better fuel economy in the Mountains. When you're running downhill in these fuel injected wonders, if you aren't calling for any power, you aren't burning any fuel. Then when you head up the hill you are running at wider throttle opening and incurring less pumping losses. The fuel injection also keeps the fuel air ratio right, unlike the old carbs that got richer when you climbed, or even just opened the throttle wide.

The other thing is that you probably don't travel as fast, and that can have a bigger effect on those drag numbers than the air density. Form drag (the part that comes from pushing the shape through the air, as opposed to induced drag, which comes from making lift, and isn't of much concern to truck drivers) increases as the square of airspeed, at least at the relatively small Mach numbers that we experience in trucks, but it is lineally related to air density. (At the same speed, 1/3 less air drag at 10,000 feet than at sea level. At 57 mph only 1/2 the drag of 80 mph (both speeds at same elevation). Combine the two effects and you can find yourself overcoming only 1/3 of the wind resistance at 10,000 feet and 57 mph that you had at sea level and 80 mph. The only down side is that, unless you have a turbo, you only have 2/3 the horsepower to do it with, and the rolling resistance and mass of the vehicle haven't improved at all, so hill climbing and acceleration are not like at sea level.

noobie1 · November 2001

All good points worthy of ponder. You've answered some things I was wondering about (one being whether 1/3 less density translates directly to 1/3 less drag at the same speed). Being a flatlander I don't have much experience up there, and that only in carburated vehicles which got horrible mileage. Thanks a lot for your interest in my education.

-David

lauriet1 · December 2001

I've decided to purchase a GMC 2500HD Sierra. It's a used model with 14K miles. Clean Title, etc from Car Fax. Looks like it was a demo - Hitch has never seen a receiver. 2500HD SLE 8.1 with Alli 5 Auto OD Tranny, 4.10, 4WD, Tow package, XCab, 8Ft Bed.

I plan to drive it to work 16 miles one way 5 days per week. I will be pulling a two horse trailer (approx 3,700 lbs loaded) and a slide in camper (Low profile, light weight crank up style -1500 - 1700 lbs there). I will only be towing about 15 - 20 times per year during the summer months (May through October), distances of 22 to 80 miles depending on destination. I know this is alot of truck for these requirements, but I plan to keep it for awhile - at least until it's paid for :>)...and my longterm goal is to go with a gooseneck trailer in about 3-4 years.

I see alot of stuff out there on this truck, but short of sifting through thousands of posts I would like to ask the readers about a couple of things.

What's the weird metal thing that sticks out from between the seat bottom and back of the captains chair that looks like it poked out of the material by mistake? Is it normal?

Other than the cold knock and the oil consumption are there any other things I should be on the lookout for based on my driving habits?

I'd like to replace the tires, any recommendations?

This will be the first vehicle I've owned which is older than a 1992. I've had an 83 Suburban and 88 Suburban and a little car-1992 Eagle Summit. I'm a bit confused about the synthetic oils / rear axle lubricants and pink antifreeze. I know I can read about these things in the owners manual, however the one in the truck is written in French (truck was built in Canada). The dealer said he would get me an english owners manual, but I don't know how quickly that will arrive - I've heard it takes about 3 months to get one. Can anyone provide basic information on maintainence of the lubricants?

Any information you provide will be greatly appreciated. Thanks for taking the time to read this over. Looking forward to your responses!

mgdvhman · December 2001

Are you talking about the track the seat slides on?

255/85/16's look good on these trucks..

Good luck

- Tim

kanton1 · December 2001

gear to drive the allison tranny in for in-town, day to day driving? I am used to the 4 speed autos where 3rd gear has lockup and is used for stop and go driving at speeds less than highway. on the new allison there is no lockup, and 3rd seems to hold the engine at higher rpms.

What have you guys that have the allison been doing? any comments and suggestions would be appreciated, thanks

kyle

kg11 · December 2001

Laurie the metal thing in the passenger seat is a child seat anchor.Other problems to watch for,Allison tranny shift problems(I had my trans replaced twice under warranty)only in the earliest few units.If carfax was clean and you have'nt got stuck in a particular gear you should'nt worry.If you're gonna keep it a long time go with synthetics.O yeah,I think all of these trucks were built in Pontiac,MI

kg11 · December 2001

You have 2 choices D and 3.As you said,3 keeps the rpm's up.It uses more fuel but wont hurt anything(I don't think).But personaly I just put it in drive.

eric2001 · December 2001

Are you still in the running for the truck? Not sure on the metal piece on the seatbacks? The two problematic issues you already noted. I will be driving it in next week, in case you wanted to look.
-Eric

4x4man · December 2001

The metal brackets in the pass seat bottom are child seat anchors. Give the truck good clean gas and good oil and it wil treat you well. Other than the cold start knock that my 8.1L used to have and a couple of rattles that I have fixed or in the process of fixing, this truck is flawless and is definitely a cowboy caddy!!!

Bob

lauriet1 · December 2001

The beast is mine! Just waiting for the check to arrive. I sure will take a look at yours next week. Maybe we can do a side by side comparison :>)

lauriet1 · December 2001

Thanks for all the responses! The metal thing is a child seat anchor huh, was that an option? (kidding). Hard to believe it was put there on purpose as it's really distracting and unattractive. Any way to get rid of it?

To kg11 - This truck has a maple leaf sticker on the door panel - 1st registration issue with 0 miles was at Quebec Motor Vehicle Department dated 3/2/2001. Sure looks to me like it was built in Canada, especially with all them funny french words in the owner's manual (Smile) I've heard that they do some initial frame assembly in Canada and then final drive train assembly in Michigan but I can't attest to that as fact. Thanks for the tip on the tranny. Two test drives in the mountains didn't show any sign of problem there. I was quite impressed with the transmission actually.

4X4man - Any recommendation on the mfr. of "good oil, good gas"? I've used Mobil Gas in all my vehicles, plan to continue. As far as oil goes, what do these trucks come off the line with? Is it possible to switch to syn oil if the truck hasn't had it before? (I can see everyone laughing at that question now - Come on guys, I'm just a lady trying to learn about her new truck). How'd you get rid of the engine knock? I listened for it on my 2nd test drive and didn't hear anything but the outside temp wasn't that cold at the time. On my first test drive I started it up a couple of times while it was warm and didn't notice anything unusal then either. I guess I'll just keep my fingers crossed and hope for the best.

Thanks for all your replies.

4x4man · December 2001

I really don't have any recommendations on gas manufacturers because I really don't know. I have found that some gas stations give me better gas mileage than others and my driving habits tend to stay the same. I just stick with the gas stations that give me the best mileage and I figure that it is good gas. Pretty unscientific but it works for me!
On the oil, I put synthetic in at 3,000 miles. That is good oil IMHO...I am using Mobil 1 5w-30 but there are a lot of other good synthetic oils on the market.
If/when you switch to synthetic there is no need to flush the engine as the dino and synthetic are compatible. I have heard that it isn't wise to switch back and forth between synthetic and dino oil. So if you are going to go synthetic, stay with it for the rest of your ownership.
Hope this helps!

Bob

1i2cu · December 2001

I've always used bar-reinforced ladder snow chains, the auto parts store is telling me that I should use cable type traction devices, as the 2500HD has ABS brakes. Cable type won't affect the ABS as the ladder type will.
All you people who have to cope with the white stuff, which type do you prefer ?
Just a 'flatlander' in SOCAL who needs to make a decision by 12/26/01.
Thanks in advance for your opinions.

owenm1 · December 2001

need some huskyliner front mats? I have a set....cheap
omcniff@shinbiro.com

minikin · December 2001

What with the chains? 4X4, decent tires, and knowing how to drive works just fine. Only thing chains ever did for me was beat the heck out of my fenders when they broke back when I was a kid. If you gotta carry them for legal reasons, at least get real chains with lugs so that if you ever do need them they'll actually work.
-- Don

4x4man · December 2001

I have never needed chains for the white stuff. However when my dad and I were out hunting a few years ago, we had to scratch the paint off of his when we hit some really murky stuff with his truck... We haven't had the need for chains in town here in Denver. As minikin stated, 4x4, decent tires and some smarts will get you through most ugly situations.

Bob

quadrunner500 · December 2001

One of the worst night time blizzards, Feb '95, driving the worst car ever created for winter driving, the Ford Mustang H.O. with sport radials, snow was blowing sideways, drifts were 3-4 ft, visibility zero, frozen wipers, defroster on full blast...

Driving home from Crested Butte, up over Monarch Pass, US285, Kenosha Pass, Crow Hill above Fairplay, passed scores of 4x4's in the ditch, up the hill on C470 from Santa Fe to University, got it completely sideways, saved it...kept going all the way to my driveway. And THERE...THERE I could not get up it. Had to put chains on....Grrrr!!

Today, with mag chloride, A/T radials, I may never need 4wd. Still glad to have it though, if only to get up the driveway.

minikin · December 2001

How about last May? Only things moving in our neighborhood that day, rural Parker, were 4x4's with folk that knew how to use them.
-- Don
BTW: I've had the pleasure(?) of driving Fox chassis Fords in snow/ice. Sincere congratulations on making it as far as your driveway! I stayed home that day.

quadrunner500 · December 2001

That May storm was shortly after I got the diesel. Came through Kenosha pass that day too, US 285, Turkey Creek Canyon, but no big deal compared to the hammering you took in Parker. I haven't used 4x4 on this truck, except to test, keep the seals from getting dry.

4x4man · December 2001

The blizzard in Oct 97 sticks out in my mind...I think it was Oct?? 2-3 feet of snow, didn't have a truck at that time, only my 1980 mustang soupped up with a 302. Needed to back it out of the carport to get some firewood. Made it about two feet and highsided the rear and got it stuck...waited till the snow stopped so I could get all the snow out from underneath it to pull it back into the carport...

Forgot about the May storm last year (thought it was earlier, but they all go so fast don't they??). Arapahoe road was full of 2wd trucks and vans stuck all over the place at 5:30am. They should've stayed home...come to think of it, I should've to. Luckily I had my 97 4x4 half ton at the time and made it in to work ok.

Bob

ryanbab · December 2001

Feb 98 we got zapped. No power or cable for 3 days ( i hibernated).

Drove a 2wd 97 sonoma at the time too. Got it stuck plenty of times

kanton1 · December 2001

for the first time yesterday. 189.1 miles; 23.225 gallons. a whopping 8.1 miles to the gallon!

8.1l, allison, 4.10/locker rear, all in town driving. I also don't know if the tank was absolutely full from the dealer.

I'm not sweatin' it. I know it will get better when the truck breaks in more. also, i did not buy the truck for gas mileage.

kyle

kg11 · December 2001

That's about all you get in town.I have 15000 mi on mine and get about 7.5 but like you said,"I did'nt buy it for gas mileage".Hook it up to your house and pull it up a 8% grade!Freeway mileage is about13.5 @ 65 and 11.2 @ 75
kip

minikin · December 2001

I have a tree in my bck yard; in Oct '97 it was an Aspen sapling that got the top pinned down to the ground, bent over a fence, by that storm when the back yard filled up with snow. Stayed that way until I got back there and freed it up late May or early June. Now about 15 ft tall with a really neat, graceful arch. Last May, my significant other left really early, about 4:00 am to "beat the traffic" to work; just before it all really went to hell. Took until almost noon to get her back home with the 4X4. We recovered her car from the super market parking lot the next day. Oh well, back to trucks and here's to another, potentially interesting, Colorado winter.
-- Don

4x4man · December 2001

At least we have a hope of our weather being much more interesting than our football team.....

Anyway back to trucks...noticed this morning that for the first couple of minutes if the temp is 32 or below my mirror blinks the temp then blinks ICE and then goes back to the temp. First time I ever paid attention to that. I could've just opened my eyes to the snow that was still left on the ground, but luckily those trusty GM engineers already thought of that so I didn't have to....

Bob

quadrunner500 · December 2001

Perhaps a blinky warning for ice is not a bad idea, but there are few G.M innovations I'm glad to do without...the blinky "shift" light on my S10 comes to mind, On-Star is another. Wife's caddy has message center, when it comes on...oh $hit, what's it gonna cost, "A/C refrigerant low" meant new compressor seals and $765. The "Service 4WD" message came on a couple times on my previous truck, '99 Silverado. Took it in, no problem, no service needed. Grrr!!

I don't like vehicles that assume you are an idiot, and have to tell you things you should already know, like your fuel is low, or door ajar. Who's drivin' the damn thing anyway?

jblair1 · December 2001

For those that might be interested, I changed my Transmission filter on the weekend. Allison recommends a change of the filter (not oil) at 8000KM. This was easier than changing the engine oil filter!.

Interesting note, I called the GM dealer and asked for a price on the filter. Was told it was $26. I asked for a part number and the dealer refused to give it to me. He must have sensed that I was going to shop around and offered me the filter "at cost" - $18 without being prompted. I hung up and called a local diesel shop that is an authorized Allison service center. "Allison" brand filter = $11.

Also purchased a 454 oil filter from a local Delco dealer for $4. GM dealer wanted $12.

Pays to shop around? Can't afford to let GM rip me off on parts aft spending $30K on the truck.

Jim

4x4man · December 2001

Couldn't agree more....I really could've done without Onstar being forced on me. Wish I could take that darn antenna off my roof so it looks clean, but nooooooooo they drilled holes through the roof for their crap. At least it doesn't leak, I guess I have that to be thankfull for!!

Bob

4x4man · December 2001

It seems more and more the dealer is not only trying to get your money for the truck, but also pricing the parts extremely high for our high priced parts. The grape juice and Alli filter come to mind. Dealer here wants $28 a qt for their grape juice..no thanks, Mobil 1 at $6.99 for my truck and no problems yet. Alli filter was around $25 I think from dealer, I can't remember, went to Allison distributor and got it for $9 after tax. Told the guy at the Alli shop how much the dealer wanted for it and he just laughed as he said most of the dealers buy the filters from them!!

Oh well, just like any other place that charges too much for a product, I go to another store and give my business there!

Bob

ruddster · December 2001

Castrol/Allison TranSynd synthetic Dexron III ATF $31/gallon & $7.95 for the filter from my Reno Detroit Diesel/Allison dealer versus $26/qt & $15/filter from dealer. But what really burned my behind was the dealers not knowing my Allison Tranny from a hole in the ground. One dealer/service writer told me no maintenance is required for the first 100,000 miles. My other local dealer quoted me time & parts to remove the oil pan, replace gasket, change the internal filter and refill with ATF. I told him, no thanks, b/c the allison manual states you need only to use the DRAIN PLUG in the pan to drain the fluid & only change the internal filter at overhaul!

Boneheads!!!

Jeff

rabbitrun · December 2001

I am considering purchasing a Extended Cab 2500HD 4WD and would like to get advise concerning towing with a SB vs. LB. Dealers seem to giving conflicting info (whatelse is new). Jeff (ruddster) thanks for the info on Dave Smith Motors, have already contacted them.
P.S. I live in Gardnerville.

ruddster · December 2001

Other than the slight differences in towing capacities, not much difference between LB & SB when towing. I have found that depending on tongue wt of the trailer & road surface, a SB may "buck" a little more as compared to the longer wheelbase of a LB. I would be more concerned with making sure the capabilities of the truck match your load.

See you a Sharkey's!

Jeff

4x4man · December 2001

I plan on towing a 7,500 lb 5er next year with my 2500HD EC shortbed. Outside of the shorter wheelbase, the only issue is backing the 5er into a tight spot with a non sliding hitch. The front of the 5er is closer to the back of the cab with a shortbed than a longbed. So you will have to be carefull if you don't buy a sliding hitch. The good thing I have going for me is that I will buy a rail kit and use my parents hitch for the time being to see if I have a problem, if not I will continue to use it, if so then I will buy a sliding hitch. I have been told by others that you cannot turn sharp enough doing a U turn to have the front of the 5er hit the back of the cab.

Bob

rabbitrun · December 2001

rabbitrun · December 2001

Are most of the trucks equipped with the 8.1 vs. 6.0? And would I have a problem towing a 27' 5er with a 6.0? Also dealers have been telling me that they sell alot more SB's than LB's. Got any thoughts on this? I quess this was more than 1 question. TIA
P.S. Ah, Jeff is that place you mentioned on the corner (LOL).

Steve

owenm1 · December 2001

Rabbitrun,

Go for the longbed and the 8.1
You will kick yourself later if you try to slim down. You get the 34 gallon tank with the long bed. Get the 4:10 gears as well. I've had mine 6 months now, very happy overall!

kg11 · December 2001

if you have a place to park it.They sell more S/Bs 'cuz they're easier to fit into a garage or parking space at the mall.Unfortunately they only come with a 26 gallon tank.At 8 mpg towing you've got a 200 mi range with either engine. 6.0 gets a little better milage unloaded but get the 8.1 ,owenm1 is right you'll kick yourself later if you don't
kip

yammy2 · December 2001

I have a short box crew 8.1/allison short box. I bought a slider fifth wheel hitch because I had the same concerns that I could hit the box on really tight turns or trying to position my trailer in a camp site. Well the verdict is in. I travelled around for a total of five weeks this summer going in and out of various campgrounds and not once did I ever have to slide the hitch back. I still like the idea of having the slider "just in case" but it really isn't an neccessity in my books. In addition to my travel trailer I also pull a fifth wheel flat deck trailer every 2 weeks. If all I had was the flat deck I certainly wouldn''t need the slider. My 2 cents.

lauriet1 · December 2001

their gas gauge? I just picked up my truck on friday - filled it with gas on Saturday am, let the pump run until handle popped. Gas gauge needle read under F (about 1/2 way between 3/4's and Full). Thought it to be a fluke, so I filled up again the next day and got the same reading. The needle doesn't go all the way to F on the gauge. Minor thing, but was wondering how accurate the gauge will be on the low side, if it's not accurate on the full side. - The gauge goes down quick enough, would like to see the tank full at least once. :>)

kg11 · December 2001

Today I saw a F150 supercrew ,with that tiny bed, towing abuot a 25' fifth wheel so I guess size does'nt matter.Personaly I'd prefer the manuverability of a shorter truck,but why cant they increase the fuel capacity?

LAURIE 1:My gas guage works fine.

ruddster · December 2001

Steve,

I switched from a ext'd cab LB to a Crew Cab SB with my 2500HD. I do miss the foot and a half out of the bed, but the functionality of the crew cab more than makes up for the bed space. My new truck is 4" shorter than the old one, but parking and garaging are vastly improved. Make your decision on how you will use the truck, not what a dealer says.
Regarding the 8.1 Vs the 6.0, the 6.0 will tow your trailer no problem. I would recommend getting a brochure on whatever truck you are interested in to be sure the tow ratings of engine & axle ratio match the load you plan on towing. I went away from the 6.0 engine because you cannot get a 3.73 axle ratio, only 4.10's, which are way too low for me. If you tow a lot, get 4.10's, but if you only tow a couple times a month, go for the higher ratio. Your mileage will be very close between the 6.0 w/4.10's as compared with the 8.1 w/3.73. Lastly, if you decide to upgrade to the 8.1 Allison combo, you are looking at around a $3,000 price adder!

Good luck with your choices!

Jeff

yammy2 · December 2001

I really like my 8.1/ally crew. However, just to keep the conversation going, I do have a few complaints : Number one ( and I know this may seem petty but...) those stupid little sun visors, what were they thinking? They are next to useless. I had two Tahoe's before this truck and both had extenders built into the visors. GM couldn't spend the extra dollar a visor to put in an extender? I hang a touque on the end of the visor to extend it. Looks stupid but it's either that or go blind. Very chinsey I think. Number two: up here in Canada it tends to get cold. Why is there always a cold draft coming in from some where blowing on the front passegers legs on every GM truck I have ever owned? Why I say Why???? My fuel guage goes right to full when I jamb the tank lauriet1. The bottom half of the tank goes twice as fast as the top half (by the guage). This was the same story for any of my GM's whether a car or truck. I get 13 to 14 US MPG on the highway at about 65 MPH. Seems to be the going milage looking at all the posts. It does use some oil (at least a quart) between changes but I'm not concerned, this is a huge motor, like it's 496 cu. What do you expect? It ain't know little 2.0 litre Honda. I enjoy the posts. Keep em comin. Happy New year everyone!!!

Chevy Silverado/GMC Sierra's w 8100/Allison

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