Chevy Silverado/GMC Sierra's w 8100/Allison

mgdvhman · July 2001

It's a truck trans.

Dealers even got a video addressing the whines and clunks of the Allison to let them know it's normal.

- Tim

loyalgmcguy · July 2001

Just finished installing four custom fit Husky mud flaps per the recommendations of several contributors. They fit perfect and look clean. Please accept my thanks.

rhwoodpecker · July 2001

I have the slide out mirrors (which I think are a little cheesy) on my 3500 chassis cab. They are not long enough to see around a dump bed I put on. Anybody know of a mirror I can use to see around? I tried our local truck accessory guys and they failed to come up with one. Bed is 7' 10" wide.

tramper · July 2001

Come on guys, drop those beer mugs and get back to the truck talk.
45mike1-post 695 I've got the camper mirrors on my '01 silverado. They ar'nt electric and not adjustable from inside but they are great for towing. No vibration like some of the aftermarket add ons.
As far as the gas, mine does fine on 87 oct, solo or towing. My only problem is keeping it under 75. That 8.1 is awsome! Have'nt tried it on Bud, Mickelob or Busch yet but would'nd be suprised if even ran better. Personaly I like Old Milwaukee Lite,I can get about 5mi. to the bottle doing 75. [just kidding about the drinking and driveing]
Tramper

owenm1 · July 2001

I was thinking the same, I'm still waiting for a response from GMC "unanswerable" question on no-load tire pressure.
6-7mpg, better get used to it!!!!!!!!!

4x4man · July 2001

How's your 8.1 treating you so far??
My 8.1 is still running strong, but this morning was the first time I started it with the door open and I think I have the cold knock...The first sound is the fast ticking for 1-3 seconds while the oil pressure builds up. That's ok, I can deal with that noise. Then I hear a low rattling or knocking that speeds up with a little rpm increase, goes away after about 30-45 seconds. The truck was in my garage, so it was very easy to hear. Well, I guess I didn't get lucky to not have the knock, huh?? Oh well have a 6 year warranty so I'm covered if anything happens (which I doubt) but I now understand why other people with the knock are sooo upset, I guess it takes you hearing it from your truck to understand...grrrrrr..
Got my first 14mpg tank going up to Estes Park last weekend!! Wooohoooo!!!!
Later,
Bob

eric2001 · July 2001

Been letting it sit. She has been very bad, getting into the cookie jar (gas tank) too much so I put her in a time-out. Was driving the car around, but just decided, to heck with the car...

Besides, Ryan is going to yell at me when he finds out I only have 550 miles on her after a month. hehe

As for any noise, I do hear some unfamiliar noises when I start her, but I was guessing they were the transmission, doesn't quite sound like a knock, and still seems to be there when warm. I dunno.

When has everyone done the initial oil change? Was thinking at 1K, but what has everyone else done? Anybody change out the trans filter at 5K per the updated bulletin?
-Eric

ryanbab · July 2001

550 miles in a month?

DAMNNNNNNNNNNNNN

i put 400 miles on my truck just today

eric2001 · July 2001

Getting 9mpg, Ryan. LOL
Anyways, been working all 12's all week, but on the other hand get August off, hehehe

Not to mention I have a car also.

Maybe a few miles when all said & done.

So, anyone done the trans filter yet?
-Eric

ryanbab · July 2001

16.5 mpg this past trip

loyalgmcguy · July 2001

I purchased my 8.1 CC Alli, 3.73 to pulll a 26H Prowler Trailer (with large slide) and a 19 foot Bayliner boat. My 97 GMC 5.7 vortec could barely pull the trailer and I never tried a triple. The 8.1 pulls both with ease but I can't see the boat when I tow and am unsure how to monitor how well it is pulling. I considered mirror extensions but don't think they will work as they would need to be very wide to see around the trailer. Anyone out there with experience towing two units? I'm curious how you monitor the third unit, and if you detect a sway or fishtail on the third unit, what is the recommended action?

4x4man · July 2001

I did my initial oil change around 750 miles. I am up to 2400mi and change currently and the knock just showed up. It is a knock and can be heard over the whine of the Alli and does go faster as you rev it up. I am a bit pi$$ed right now, but as I said before I know now how other people feel about it. You pay $30-40K and this is what you get. I'll take the noise over some tech guy tearing into the motor and forgetting something...no thanks!!! Oh well, we'll see how loud it gets over the next few months as it starts to cool off around here...
By the way, where did you get you Westin step bars?? I called Summit Racing and they stated none are available for the HD...yeah right, seen pics of 'em all over the web!! Local off road place has go rhino's, but not sure I want go rhino name on top of the bars...name is tacky, go figure it had to be something, huh?? :-0

Bob

ryanbab · July 2001

The westins have their name on each step.

Got my black nerf bars installed for $250 from the rhino linings place that did my liner.

4x4man · July 2001

My dad has double trailered once....and only once. The truck he has, an 88 K2500 5.7 4 spd manual, is not up to the task. He has a 28 ft 5th wheel weighing around 7,000lbs and a 19ft Bayliner right around 3,500lbs and it was a chore. He got about 5-6mpg (not bad considering!) and 0-60 was in about 2hrs if he got there..hehehehehee
He walked the whole thing from bumper of truck to the outdrive on the boat and it was like 60 or 65 feet!!!
He was unable to see the boat, and passing, well I don't think he did ANY passing, would be guess work after you see cars go by the bumper of the 5er. Also he did have a problem with sway on one part of the trip. The boat caught some wind and started to wiggle, then the 5er started to wiggle, then the truck started to wiggle. He slowed down, and probably had to change his shorts (from what he told me it got pretty violent by the time it hit the truck) and he got it under control. He has talked about putting electronic brakes on the boat, he seems to think if it were to sway again he could tap the electronic brakes on the boat trailer and it should bring it back in line. But I doubt he will get another chance to double trailer with this current truck as I finally convinced him his truck was not rated to tow that much weight and he could do some major damage to himself and property if he couldn't put the wo to the go and he would be liable for it all.
Anyway, just his experience.....hope it helps!

Bob

4x4man · July 2001

Thanks
$250 installed doesn't sound bad as the quote I got for the Go Rhino was $379 (installed by me)chrome of course..
I was thinking about going with the Westin CPS, I think that was it....now to find the darn things!!

Bob

ryanbab · July 2001

http://www.carparts.com

if they have em let me know i have a code for 10% off

Ryan

4x4man · July 2001

Never been to their website, I'll give it a shot...

Bob

ryanbab · July 2001

this is what i found

Platinum CPS Step Bars , Chrome Plated Stainless
• Usually in stock and available to ship within 2 business days. 26-1680 Pair $387.61
2000-2001 Chevrolet Silverado 1500 / Silverado 2500 / Silverado 3500 Pickup, Extended Cab, 4 Door
2000-2001 GMC Sierra 1500 / Sierra 2500 / Sierra 3500 Pickup, Extended Cab, 4 Door

pretty darn expensive

Ryan

ryanbab · July 2001

http://www.westinautomotive.com/pages/westin%20step%20bars%20platinum%20cps%20stainless%20steel.html

4x4man · July 2001

Pretty much what I was thinking when I went searching through the site...pretty expensive, oh well, expensive truck, expensive accessories!!!!
Livin' the american dream!!! Besides, that's what plastic is for right??? Pay it off next month!!!
BWAAHAHAHAHAHAAA!!!

Thanks again Ryan

Bob

loyalgmcguy · July 2001

Thanks for the triple towing warning. I also have a 7,000# trailer and a 3,000# boat, and it stretches over 60 feet. I have set up the triple twice and can report that power is not an issue, nor is speed on hills. Gas mileage is 8-9 mpg which is better than two trips.

Do you have a diagnosis on your knock? Rod? Octane? Something else?

4x4man · July 2001

I haven't taken my truck to the dealer yet so it is only my guess, but I know it has a knock. Whether it is the piston or rods, I duno, but last night after the truck had sat for quite some time and I fired it up, my wife was able to hear it. At first she was just hearing the whine of the tranny, then I told her do you hear what sounds like a horse walking briskly on concrete...she heard it then! It is not that loud, but you can hear it in the cab with the doors closed and radio off. I am going to switch to Mobile 1 synthetic when I hit 3,000 miles and see if I can have the same luck as others at quieting this knock down a bit..

On a more un-depressing note, it is nice to hear about the power of the truck towing both a 5er and boat. I currently have a boat, right around 3,000 lbs and have been trying to figure out whether to get a slide in camper or 5er and (cringe) tow the boat behind it....
Bob

owenm1 · July 2001

GMC online assistance was baffled, has no links to GMC builders/engineers. Said to ask dealer, dealer said ask GMC! I'm running as recommended on the door, even though those pressure seem way too high, but that what the book says to run for cold pressure.
Engine knock is becoming more noticable on start up.
Anyone need a set of front Husky liner front mats (L&R black) for an ext cab 2001 GMC/Chevy? email me: omcniff@yahoo.com

billnsandi · July 2001

I just took delivery of my 3500HD/8.1/Allison. It is a really great truck and I am enjoying the heck out of it. However, it rained heavily today and I noticed the overhead cubby was filled with water. I pulled the cubby and found that all of the headliner area was totally dry, so the rain must have dripped in one of the screw holes for the running lights on the roof. Anyone else have similar problems, and if so, what did you do about it?

Bill Ritchie
billnsandi@kingwoodcable.com

mrurl · July 2001

Pull the screw out, glop some silicone in the hole, and put the screw back in.

Peter

wildbill65 · July 2001

DOES ANYBODY HAVE ANY SERIOUS RESERVATIONS THAT WOULD SWAY THEM TO THE FORD DIESEL UNIT RATHER THAN THE GM UNITS?

ryanbab · July 2001

so it showed oil pressure of 0000000 and you kept on driving didnt pull over?

loyalgmcguy · July 2001

We all know that 8.1's use oil. After 7,000 miles mine uses about 1 quart every 2000 miles, more if I tow. I currently use 10-30 Valvoline but have considered a switch to synthetic. Anyone have experience with such a switch? Will synthetics reduce consumption? Will a change improve gas mileage? Are there other benefits? What brand did you switch to and why?

Note to tdmac. Like all on this site, I regret to hear you're experiencing problems. When you say it ran fine but "sounded like crap". What do you mean? Valve noise? Knocking? What does the crankshaft sensor do? Could this have contributed to your problems?

eric2001 · July 2001

or anyone else who has done their oil/lube job, is there a clearance issue that doesn't allow the PF1218 filter? The PF454 is less than 1/2 quart (appears) while the 1218 is a full quart, used on the '98 & back big blocks. 4WD, BTW.

Also, any issues reaching all the grease nipples? Should I get a 90 degree fitting for the grease gun? I do have the skid plates, is this an issue?

Thanks,
-Eric

billnsandi · July 2001

Has anyone had success putting aftermarket wheels on their 3500HD 4x4 (Alcoa, Eagle, etc)? I heard from an Eagle Alloy dealer that the front hubs and mounting surface on the '01 3500HD 4x4 have been slightly altered from previous years and that the wheels don't seat properly causing vibrations. Any thoughts on the matter?

Bill R.
'01 3500 HD 4x4 8100/Allison

dddavel · July 2001

Has anyone on here put a body lift on a 2500HD ext.cab yet? If so, What brand was it? Did you raise the bumpers also? Did you have to modify anything you didn't expect? Did you talk to your dealer about warranty work issues? I can't understand why GM makes these trucks sit so low and puts the smallest tires on of any of the big three brands.

4x4man · July 2001

I know there isn't much room under the oil filter, but not exactly sure how much. I beleave either the front drive shaft or the exhaust pipe is pretty close to the bottom of the oil filter. I'll give a look see tomorrow and let you know. By the way are you having any luck finding the PF454 filter anywhere besides the dealer???

Bob

eric2001 · July 2001

Autozone is getting me 4 for $3.49 each. Too bad, Walmarts sells all the AC's for $2.18. What about the trans filter? and fluid?

Going on a road trip this weekend, 3-400 miles, so I will do the initial filter/lube tomorrow (800 miles), but I am planning on changing out the trans filter before/by the 5K mark. Allison recommends the Castrol TranSynd. Any luck trying to find this? Does GM approve of it? Oh well, the joy of vehicle maintenance isn't too bad in the Summer.
-Eric

woolyback · August 2001

Hi everyone, has anyone followed up on the information that (4x4man) gave us regarding the filter change on the Allison trans.
Has anyone asked the dealer about it ?
I checked out the Allison web site but got more confused the more I read.
It starts out talking about the equipment affected and lists a bunch of stuff that doesn't make sense to me.
How can I find out whether I have the WT, AT, MT, or HT Series. I have the 2500 HD truck.
I've looked at the paperwork I got with the truck and the owners manual but can't find anything that explains it.

4x4man · August 2001

I checked under the truck (sorry took so long) and there is only about an inch of clearance between the bottom of the oil filter and the top of the front driveshaft. Oh well, would've been nice to have been able to put the larger filter on...maybe 2wd trucks would have better luck??

Haven't started looking into the tranny fluid yet, I will wait until its 25K change and probably start it on the synthetic track then, not sure which brand I will put in yet.

Bob

4x4man · August 2001

Now a days I don't trust the dealer, especially after I went to the dealer yesterday to get info on the infamous grape rear end fluid. At first they told me Mobil 1 was ok (75w-90) then they came back and said no you have to use GM's stuff or else warranty won't be valid. I then asked how much it was, $28 a qt!! I told them you have to be $hittin me!! They also asked me why I was changing the rear fluid so early I told them about the 500 mile towing bit...they just about laughed me outta the parts area....but wait it gets better...I asked them why Allison requires the external tranny filter change at 5,000 miles, yet GM doesn't.. There only answer was if GM doesn't tell you to do it, you don't have to. What a friggin joke.... By the way I heard someone somewhere that the filter was only like 10 or 15 bucks, cheap peice of mind, at least Allison knows how to build a transmission, which is more than I can say about GM and their motor building tolerances.....
Anyway, I guess I am 0 for 1 to validate the Allison filter change...but for 10-15 bucks, I'm gonna follow Allison on this one....

Bob

ryanbab · August 2001

"infamous grape rear end fluid"???

is it the synthetic stuff?

$28 a qt wow i paid $26.

4x4man · August 2001

Yup the synthetic stuff...
$26??? Man I guess I don't feel soooo bad???Grrrr....
Can't someone make something that is spec'd for GM??

Oh well, guess I'll just bite the bullet and go get 4qts of the stuff...
$120 bucks for rear diff fluid COME ON GM!!!!!

Bob

4x4man · August 2001

Went down to Autozone to see if they could order some PF454's and the doofus behind the counter tried, but it shows that it is not available for special order. Any hints on how I can lead these fools down the path to help me get these filters??

I got a chance to check out the PF1218 while I was at Autozone and I think it would be a close fit, I only have about 200 miles till I'm gonna change to synthetic, maybe I'll buy one of those also and see if it will fit and clear the front drive shaft..what's the worst that could happen....I just take it back, unused, and get my money back and put the dealers gold-laced PF454 on there!!!!
Man 10 bucks for an oil filter, 28 bucks for rear end fluid...naw their not ripping us off or anything....grrr sorry still venting....
Bob

woolyback · August 2001

I took my truck into the dealers today it has 7000 miles on it. I showed the service rep. the Service Information letter that I printed off the Allison web site but he didn't know anything about it and said that Allison won't tell them much about the transmission at all.
I was getting a free oil change out of GMC for causing me grief with my transmission the time that it locked up. So I decided to go ahead and bite the bullet and get the trans. filter changed. I only hope the mechanic who did it remembered to replace the magnet on the new filter. I get the uneasy feeling everytime I take my truck into the dealers that I'm not in charge of my own destiny.
The filter and fluid cost #23.85. I have to take the truck back in tomorrow. I had asked them to rotate the tires while it was in the shop and they forgot, I'll find out how much the filter cost.

I heard somewhere that you could take your GMC vehicle to the Chevy dealer for warranty work. I think I'm going to check it out tomorrow also. The Chevy dealer is much bigger and has sold more of the trucks with Allison trans. so hopefully they have more experience with them. The GMC service rep.told me they have only sent one mechanic to school on the Allison trans.

eric2001 · August 2001

I finally broke into double digits with my mileage. Driving 70/30 (highway/city) I got 12.5 mpg. Yee-ha!!! LOL

Bob: the PF1218 won't fit if you have 4WD, the front driveshaft is in the way (universals really) and the PF454 is tight enough trying to keep it upright as to not spill the oil. As for Autozone, they listed the PF454 as a stock item, and got some delivered from another local store for me. Still wish I could get Wal-Mart to order some & get 3 for the price of 2 at Autozone. BTW I contacted AC, and there isn't a Ultraguard Gold available yet in the 454 size.

As for the trans filter & fluid, I am under the assumption that I will need to top off the fluid when I change the filter, that was why I was asking about the Castrol synthetic that Allison recommends. Might be worth it considering they claim it doubles the service interval...

Woolyback: the HD's Allison trans is the 1000 series transmission. Also; filter magnet on trans? Where is it located? Does anyone know if there also is an internal filter on the trans?
-Eric

4x4man · August 2001

First off, its nice to hear you got the mileage that I and others have got on the highway!!!

Well, maybe I will try another Autozone sometimes the computer IS smarter than the so called parts person behind the counter.. :-)
So far my local Wal-Mart doesn't have the PF454 either, guess I'm stuck with the dealer again if another Autozone can't figure it out. We'll see.

I only have about another 100 miles until I hit 3,000 miles on the big pewter beast and then I'm gonna switch to synthetic in the motor (Mobile 1).

On the Allison filter, the magnet, from what I have read, is right on top of the filter. So when you unscrew the filter, the magnet should be right on top of it. Take the magnet off the old filter, clean it and put it on the new filter, prefill the new filter with tranny fluid and you will just have to add a little more fluid once you get the tranny up to operating temp specs at least 160-190 degrees I believe. There is an internal screen filter inside the pan, but from what I hear it doesn't need to be replaced until the tranny is overhauled!!

On the Castrol tranny fluid, I don't know if i trust Castrol after the crap they have pulled with their motor oil. Got a good chuckle at the parts store over the weekend when I noticed Castrol also has a synthetic blend right next to the Syntec!!! Unbelievable!!! Both are blends I can't believe those bastids!!! Oh well, like I said earlier, I'm just gonna change the external filter at 5k like Allison recommends, then change the external filter and fluid at 25k and re-think my opinion on Castrol or just go with Mobile 1 in the tranny also and continue 25k filter and fluid change intervals.

Sorry for the long winded post!!

Bob

shroll · August 2001

Does any one have this combination that could give me an idea on gas mileage that I might except. Dale

perfogre · August 2001

SChroll, 8100 CC 3.73 265 tires 10mpg city, 12mpg freeway @80mph

n75v111 · August 2001

10.0 B&F to work for from day one (5000mi now)

Pulling 10500lb 5th wheel thru lots of hills around the Mississippi river valley DSM to OSH Round Trip about 800 mi 7.8 to 8.0 on cruise at 65 up and down the hills so not the economy way to drive it under those road conditions etc.

Used about a qt of oil //
Tow-Haul mode
At 65 RPM in 5th -2350, up slight grade shift to 4th RPM around 3200 & the steep ones shifted to 3rd RPM up to 4000 all the time maintained 65

75v

eric2001 · August 2001

Thanks for the info. Let me know if the M1 quiets the start-up knock. Yup, jumped out of the truck yesterday when I first started it, sounded like a d-max for 10 or so seconds. Guess I have been wasting $$ on premium for no reason. Seems like I need to go get my free extended warranty. For those that got the extension, what do they offer? Is 5/100 the only choice? Thanks. -Eric

4x4man · August 2001

My only issue, is that I bought an extended warranty when I bought the truck, 6 year 60,000 mile, thinking I was gonna keep it for a long time. Unless there is a case where they refund the money you paid for the warranty (which I doubt) and then give you a free 100k warranty I think I am out of luck... I guess I won't know till I go to the dealer to have the "offical word" that it does have it and find out what my options are. Fingers crossed that M1 will quiet it down so I won't have to bother with this!!

Bob

obyone · August 2001

Check the fine print on your extended warranty. I've cancelled mine in the past and received full refund. Course I did it within the first three months of owning the vehicle.

2500hd · August 2001

Now the 8.1 is knocking like the 6.0? Guess a Super Duty will have to do .

4x4man · August 2001

I will check that later today, I would assume I wouldn't have a problem either from what you say, being as that I have only had the truck for almost two months...
Thanks again, I will check into it!!

Bob

Chevy Silverado/GMC Sierra's w 8100/Allison

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