okay...so ive read plenty about LLys over heating...heres the thing...my 05 2500HD has done its share of towing...its a very late model 05...has about 45000miles on it and tows 3 different trailers or at least 2 now...

i have towed a 16 foot haulmark all over the place (maybe 6000lbs fully loaded at most)

i tow my 39 foot fifth wheel (16000lbs fully loaded)

and in louisianna i did hurricane work for 8 months and my dump trailer weight just shy of 10000 lbs with loads up to and over 15000lb with in...
in other words ive towed 25K in the heat of the south many times and still have not had my engine over heat....now there were times where the trans climbed to around 230ish but the engine never went over 220 and 99% of the time stayed at the 210 mark like its supposed to run...

is it possible in late 05 the problem fixed or is this a random issue?

okay now on to my question...my gas mileage kinda blows with this thing...were talking less than 12 around town...any retunes offered by GM or quick fix chips out there to correct this? i have plenty of power so could care less about that aspect.

3rdly...what other issues are there for 05 if any?

thanks

My truck was built 10-04 so it's not a "late-build" 2005. I've pulled my TT all over south Tx in the heat & humidity-never came close to OH or even running hot with the mods I've got. There's obviously an issue on some of these trucks but mine's not one of them...

My truck was built 10-04 so it's not a "late-build" 2005. I've pulled my TT all over south Tx in the heat & humidity-never came close to OH or even running hot with the mods I've got. There's obviously an issue on some of these trucks but mine's not one of them...

I'm sure this will cause and yet another debate.....

My 04.5 was built 1/04 and it was NOT an overheater...



There is nothing wrong with the LLY motor...

I have 34,000 mi. and pull a 37 ft. fifth wheel or a 35 ft. boat. Never an over heating problem, never has my clutch fan come on. Just took a 6000 mile trip through NEW ENGLAND and CANADA , NOTHING BUT PRAISE FOR MY 05 LLY.

The wiring connection for injectors #2 and #7 can break unexpectedly.

I don't know what percentage of them eventually go.

Mine has been trouble free to 26000 km = about 16000 miles

Hauling 3500 lb camper as you see it up long hills in hot weather the cooling fan does come on, but it brings down the temps pretty quick when it does.

My mileage on a long trip recently with no significant load, two-lane country highway lots of hills average speed around 60-65 was 18.4 US MPG

Love my LLY, Tow 8500lbs through mountains of WV and PA no overheating? 30,000 miles now. I like this truck more everytime I use it.:D O-by the way three steering shaft repairs, and one fuel temp sensor replaced. MT 18.5 mpg, loaded 13 mpg :)

Mine is the best truck Ive ever owned. Zero problems, tons of power and never overheated.

Never overheated but the fan runs more than my lb7 did but it still pulls my 16k toyhauler all over eastern US and canada....

There is nothing wrong with the LLY motor...

I was really going to stay out of this one, but........

Technically, I would have to agree with Unit453's statement. I believe the LLY motor is a great motor. I will have to say that my truck's fan runs like crazy in the summer as compared to the LB7 I had. I also understand that the goal of the fan is to reduce engine temps when excess heating occurs. It's more annoying than anything else.

I do believe, however, that any of these motors will OH under the right conditions. Like pulling a 37' fifth wheel during the hottest part of the summer at posted speeds over the divide or taking on some of the massive grades that exist in the western states. What many of us do to compensate for this possibility is adjust. We either don't go, wait until it is much cooler outside or tackle the situation by running at a snails pace and pulling over frequently to prevent the engine from getting to hot. Therefore, we can say that we have never over heated. Now before you all start to flame this post, please understand that I used to have a 37' Class A with a Cat 275 Turbo diesel that would red line the temp gauge under the very same situation. As a matter of fact, it would red line while running 70 MPH on a flat road with OAT's in the mid 90's. My point is that all engines have their unique characteristics. We learn what they are and either live within the engine's limits or modify the power plant in some way.

As for the original question, the wiring harness issue (which I prevented) and the steering shaft bump are the only "05 LLY" issues I have had.

Good luck!

Mine is the best truck Ive ever owned. Zero problems, tons of power and never overheated.


:exactly: same here

X3 as above.

Mine is the best truck Ive ever owned. Zero problems, tons of power and never overheated.

Mine too.:ro)

No Issues With Mine .( 23k ) Tow A 31 Foot Tt And Never A Over Heat Problem..
My Only Complant Is I Wish I Would Not Have Gotten A Black Truck.. Never Looks Clean For More Then 30 Min..

Arm

same here no mods no over heating, i didn' buy it race, but to pull with and no complaints here, if i want to go fast i get in my vette or on my motorcycle.:)

20,000 miles no problems:)

we tow 16k going threw pa doing 75-80 with no problems. it goes about 220 and thats it. the trans on the other hand i wish it would run alittle cooler.

No Issues With Mine .( 23k ) Tow A 31 Foot Tt And Never A Over Heat Problem..
My Only Complant Is I Wish I Would Not Have Gotten A Black Truck.. Never Looks Clean For More Then 30 Min..

Arm

Once you have had a black truck you will never own another!

Been there, done that!

I hate my lly. Just wish I could sell it for a LBZ without taking a loss.

Once you have had a black truck you will never own another!

Been there, done that!

I'd have to dissagree with that one. I love black on a truck...or on most any vehicles for that matter. Yeah, it is hardest to keep clean but I just cleaned it a lot. :D I still wish my new truck was black sometimes even though it's noticably easier to keep clean.

I agree. My whole fleet is black....!

I have experienced the over heating thing once, steering shaft knock, leaking p.s. line, and poor fuel milage. My milage was hovering around 12-14 until the ulsd hit here and I am seeing 16ish had calculated with it? Truck also broke 30,000 in that time period. I pull something about 3/4 of the time ranging from 12,000 lb 5th wheel to 6000 lb box trailer. I have a low speed/ idle surge that the dealer won't reflash for a fix. Over all truck has served me well although I am not 100% confident in it.

Merry Christmas
Tom

My '05 drw 2wd ext cab just went 100K on my last run to Idaho...grossing about 28,000 lbs! And my friends that is my average gross weight!
The truck is 16 months old. The only problem I ever had with it and not the truck was the STUPID EDGE box! Took it off and put a Bully Dog Power Pup on it about 60K ago with NO MORE problems!
Does my truck run hot? Only when its 110* plus outside and I'm loaded! You just drop a gear in a long hard pull and turn up the A/C another notch and keep on truckin'! lol :rolleyes:
Jerry

My '05 drw 2wd ext cab just went 100K on my last run to Idaho...grossing about 28,000 lbs! And my friends that is my average gross weight!
The truck is 16 months old. The only problem I ever had with it and not the truck was the STUPID EDGE box! Took it off and put a Bully Dog Power Pup on it about 60K ago with NO MORE problems!
Does my truck run hot? Only when its 110* plus outside and I'm loaded! You just drop a gear in a long hard pull and turn up the A/C another notch and keep on truckin'! lol :rolleyes:
Jerry
the 28000 your referring too...is this trailer weight? or combined weight...just curious...

First I've heard about overheating problems. Mine is also 04.5 LLY. Weird thing happened last week though. Took it in for serviciing last week at 19,000 mi for oil change ect and the service rep calls to say that my tranny fluid is so black, they described it as burnt. Proceeded to sell me Transmission spin off flush ect.
My family is full of Mechanics and diesel enthusiasts ( I'm the only one with Duramax)
Chrstmas day family all states this sounds highly suspicous for milage and all and said they probably up sold me, being Lady with a big truck and all.
I haul a horse trailer about 3200 lbs, fully loaded max I'm coming in at 7- 8000 lbs

If it's true how hot would my Tranny have to get to burn the fluid like that ?

Not sure what to think.

No issues with mine overheating unless if you define overheating as the clutch fan running quite consistently when it's in the upper 90's, it does that alot so if that means it's overheating then mine is overheating. I tow a 12K pound toy hauler in the Oklahoma/Texas heat, mileage sucks but it's kind of expected. I have around 28K miles on mine so far, it's a 2004.5 with the LLY motor.

Yes, please define. Are you stopped on the side of the road, Temp gauge is ?

The temp gauge is very inaccurate. You need to hook up another gauge to really see what is going on. You will be very surprized to find out just how hot the lly gets in the summer. In the summer my temp gauge reads 210 but the temp is actually 223 or higher and the gauge only lies even more from there. All of the info above is while towing 6k in the summertime. The fan will engauge for ten minutes straight only to stop for two minutes then engauge for another ten minutes for an entire 7 hour trip on my way to Utah.

Is your computer messaging that you are overheating ?

First I've heard about overheating problems. Mine is also 04.5 LLY. Weird thing happened last week though. Took it in for serviciing last week at 19,000 mi for oil change ect and the service rep calls to say that my tranny fluid is so black, they described it as burnt. Proceeded to sell me Transmission spin off flush ect.
My family is full of Mechanics and diesel enthusiasts ( I'm the only one with Duramax)
Chrstmas day family all states this sounds highly suspicous for milage and all and said they probably up sold me, being Lady with a big truck and all.
I haul a horse trailer about 3200 lbs, fully loaded max I'm coming in at 7- 8000 lbs

If it's true how hot would my Tranny have to get to burn the fluid like that ?

Not sure what to think.


my brother is a service writer at a GMC store...we have been doing trans flushes regularly on mine and he wouldnt try to upsell me...no benefit to him really... but he used to do some of the flushes and has seen many with between 20 and 24k that had black trans fluid...i dont know if they burn or just discolor but i wouldnt think you are getting fed a line of BS...i have 45k and have flushed mine 3 times already...tranny flushes are a hell of a lot cheaper than replacing an allison. warranty is over on the allilson at 36k...so unless you have an extended warranty your tranny warranty is up about the time that your diesel is breaking in LOL

A little of topic, but change your spin on tranny filter every 10,000 miles. Alley will Love you for it!:)

The temp gauge is very inaccurate. You need to hook up another gauge to really see what is going on. You will be very surprized to find out just how hot the lly gets in the summer. In the summer my temp gauge reads 210 but the temp is actually 223 or higher and the gauge only lies even more from there. All of the info above is while towing 6k in the summertime. The fan will engauge for ten minutes straight only to stop for two minutes then engauge for another ten minutes for an entire 7 hour trip on my way to Utah.

"very inaccurate" is sort of a stretch. all factory gauges are damped, apparently not everyone knows this. according to the temp gauge thread on another site, the factory gauge will sit at 210 from ~190-~220. call me crazy but i would assume that is where gm thinks the operating range is. i also suspect this is an attempt to avoid unwanted temp gague diagnoses when the owners bring their truck back wanting to know why the gauge moves through that range........as i mentioned it was a surprise to quite a few people that the factory gauges are damped.

as for the fan, i agree that gm should get with the program and let the computer control it. ive seen mine come on at some strange times, besides the morning, when the engine was no where near hot. i have this same fan complaint with my work truck, 2005 international tractor 330 hp/ 1200lb torque cummins select, running on the flat interstate 65mph in the dead of summer with an empty trailer (gcw 28,000lbs) the fan will cycle continually on and off. not much ryme or reason to it..........and it IS controlled by the computer???????? no factory conspirasy here, its a full blown "big boy" work truck.

"very inaccurate" is sort of a stretch. all factory gauges are damped, apparently not everyone knows this. according to the temp gauge thread on another site, the factory gauge will sit at 210 from ~190-~220. call me crazy but i would assume that is where gm thinks the operating range is. i also suspect this is an attempt to avoid unwanted temp gague diagnoses when the owners bring their truck back wanting to know why the gauge moves through that range........as i mentioned it was a surprise to quite a few people that the factory gauges are damped.

as for the fan, i agree that gm should get with the program and let the computer control it. ive seen mine come on at some strange times, besides the morning, when the engine was no where near hot. i have this same fan complaint with my work truck, 2005 international tractor 330 hp/ 1200lb torque cummins select, running on the flat interstate 65mph in the dead of summer with an empty trailer (gcw 28,000lbs) the fan will cycle continually on and off. not much ryme or reason to it..........and it IS controlled by the computer???????? no factory conspirasy here, its a full blown "big boy" work truck.


I would not have an issue with it operating at 220 and you might be right about the operating range, but as stated before my temps go north of that in a quick hurry with a load of 6-7k. I don't consider 235-250 a normal operating range while traveling with a load under specs.

I do think the gauge should be more accurate then it is though because is is not telling the truth. Hell if 220 was ok I would put an electric fan and start feeling good about the truck again.

Yours is worse than most if your overheating when only pulling 6-7K but I can assure you that your not seeing 250. At that point it will blow the cap off the reservoir and boil over. The highest mine has seen was 221 while pulling 16K up a grade with my foot in it. The gauge was reading just below 210.

Yours is worse than most if your overheating when only pulling 6-7K but I can assure you that your not seeing 250. At that point it will blow the cap off the reservoir and boil over. The highest mine has seen was 221 while pulling 16K up a grade with my foot in it. The gauge was reading just below 210.

Not true,

I have puked out coolant(engine coolant hot message with gauge pegged) in july pulling Baker grade pulling 7,200 and 115 degrees. I have been dealing with GM for some time now and every attempt has failed.

a good afe stage2 intake and free flowing exhaust can combat both low mpg and overheating.

a good afe stage2 intake and free flowing exhaust can combat both low mpg and overheating.

I have a 4 inch exhaust and the X-box on it now. Gm wants to put on the 06 airbox but I have refused to install it until they can prove it will work. I will probably have to install it just to jump through the gm hoops. :(