Well the time will be coming up in a few months to buy a new rig, and this time I want to make sure I make an educated decision. My wife really likes the chevy's, so I may be leaning that way (I like them too).

I know the chevy motors were different, and they made improvements as the years progressed. What were the issues, and when did they fixthem?

Whatis the best year to get?
What years had what issues?
What is a good price for these years?
Where is the best palce to get them?

Dima

the first year or two had issues with injectors leaking. '04 or newer should be fine. They also hold their value pretty well. When I was looking, trucks with 70-100k were still aking $22-27K. I would have bought one, if I hadn't found the deal I got on my Dodge.

grab the 04 to early 06 chev or gmc, before they switched to the next duramax engine ( current) those have all the problems answered for the previous years and you can get some serious power out of them with a couple go-fast goodies.

If you run a search you'll get a few week's worth of reading on the subject... :smokin:

I've got an '06 LLY that I love. The '06 LLY and '06-07 LBZ motors came with the 6 speed Allison transmissions. The '05 LLYs had some problems with overheating when towing IIRC 10k+lbs. Early ones had injector issues. I'd definitely try to find an '06 plus, they have the strongest Allisons, the most power, and no big issues. dieselstop.com has a lot of info on the Duramax trucks.

The Pirate board of Duramax........

http://dieselplace.com/forum/

x2 on dieselplace.

great site (I'm a member there as well) and tons of info

IMO, if you get an LB7 ('01-04), then just make sure the injectors have been replaced under warranty. mine were replaced at 73K. I bought the truck with 97K on it. it now has 110K and runs great. I added some tuning and exhaust and it runs like a raped ape when I want it to.

tows awesome, was a great deal, and has been a solid truck so far. I tow about once every other month for wheelin. rig/trailer weighs about 7500#

mine has the 5spd Allison. mine is super clean, decent mileage and I got for less than 20K (it's pretty much fully loaded)

happy hunting :D

The Pirate board of Duramax........

http://dieselplace.com/forum/

NOT the pirate of Duramax...I've seen people start shitstorms for cussing about a product. :laughing: And NO ONE will take any criticism the right way over there. But it's got a lot of info, I read a lot more over there than I post.

I would kill for an '06 because of the second overdrive 6 speed tranny. I have zero complaints about my '05 but I sure would love that second overdrive on a 75 MPH flat expressway when towing.

Chevy had the best highway ride and was the quietest inside. That's what I cared about in the tow rig decision (outside of the Duramax/Allison).

I've got the '06 LBZ with the 6 speed Allison. Great truck. Even better once I added the air bags.
No problems at all in the year and a half that I've owned it.:smokin:

NOT the pirate of Duramax...I've seen people start shitstorms for cussing about a product. :laughing: And NO ONE will take any criticism the right way over there. But it's got a lot of info, I read a lot more over there than I post.






Yeah, I was refering to the info avaliable on that site.


FWIW Flatty I have a 05' crewcab and love it. Hands down the best truck I have ever owned. The 06's have the 6 spd tranny :smokin: and a little more HP & torque. I dont think there are many problems with the 05 and up models. Read a little on the diesel place and it should answer most of your questions.

So I read a bit about them, and here is what I gather:

Gen 1 has injections issues
Gen 2 has overheating issues
Gen 3 is pretty solid so far

DIma

in a nutshell. but, if the gen 1 has had the injectors replaced, then it's as solid as any other version.

good luck with your choice

So the injectors are NOT a recurring problem? Once theya re fixed, I don't have to worry about cracking a piston?

How long do these last?

Thanks
Dima

I'm no expert, I'm just going by what I was told (by a reliable friend who works on them)

they don't seem to have any problems after the injectors are replaced. they are warrantied up to 200K. the injectors were first replaced with the same style and they then realized that it was the actual injector causing the problem. once they figured that out, they went to a different style injector and now that problem is solved.

only other thing that "might" be an issue is a rail leaking, it'll give you the same symtoms and lead to the same result if not fixed.

my injectors were replaced at 73K and I bought the truck with 98K. it now has about 112K on it with no problems. motor runs great, tows awesome and I have a little extra into it as well :D

IMO, getting an LB7 that already has had the injectors replaced is a good truck to have.

if i were to do it all over again i would not change a thing.
i have an '03 (lb7) with some goodies. awesome truck! with a little tuning these trucks will be very fast and powerhouses.
i have rode in an '05 (lly) and an '07 classic (lbz) both trucks ran the edge with att monitor and ran very very hot egt wise.

no complaints about my truck and it pulls everything that i need including a 25' 4 horse slant trailer with living quarters with ease and most importantly with comfort.

Gen 1 (LB7) best years are 03-04
Gen 2 (LLY) Only good year IMO is 06', most are overheaters
Gen 3 (LBZ) All good
Gen 4 (LMM) good so far, but lots of emissions crap

I would look for either a 04 LB7 truck, or a LBZ truck.
I have an 02 that I have been abusing for 100K miles with 1 set of injectors being the only major thing done, I havent even touched the brakes yet. 01's and 02's do have a 200k warranty on the injectors

I wouln't own a truck with an aluminum head. It is always expanding and contracting at a different rate than the block - no way... That goes for any engine in my book. What's the point anyway - to save 75 to 100 lbs? I know I'm just talking to myself here though.....

I wouln't own a truck with an aluminum head. It is always expanding and contracting at a different rate than the block - no way... That goes for any engine in my book. What's the point anyway - to save 75 to 100 lbs? I know I'm just talking to myself here though.....

I agree, I mean, its proven to be a MAJOR problem on ALL Duramax's so fa-wait no it hasn't :shrug:

42K on my LLY and I love the truck. It does get hot though, I am putting in a gooseneck to pull a 2 car trailer, and I will also be installing a rad V2 to keep it cool. Seems to be the ticket for cooling them properly. I think its BS to have to spend an additional 900 bucks to keep it cool, but it could be worse. Overall a great truck, no regrets.

I wouln't own a truck with an aluminum head. It is always expanding and contracting at a different rate than the block - no way... That goes for any engine in my book. What's the point anyway - to save 75 to 100 lbs? I know I'm just talking to myself here though.....

Yea, all those damned aluminum pistons have the same problem huh.

The '05 LLYs had some problems with overheating when towing IIRC 10k+lbs.


Gen 2 has overheating issues
DIma


Gen 2 (LLY) Only good year IMO is 06', most are overheaters
Gen 3 (LBZ) All good



do some more research. the lly overheat issue is not at 10k lbs. it has to do with large air damn/wind drag towing situations, in addition to a HEAVY load, in 100*+ weather up long steep grades. this means mainly large, TALL, 5th wheels, running near the max tow capacity of the truck (15k). i here the rumors often of the so called overheaters, as i have one. fact is, 90% of these rigs don't meet the requirments to overheat. but that's not good enough to beat the stigma.

my 5th wheel/truck combo has been scaled at 26k (gross is rated at 22k), is over 13' tall and got fairly warm, but never overheated. and i have power adders and push it hard. i've also drag raced it and ran a 14.5 et. i've added cooling capacity to it as a precautionary measure and have never had a problem?

stock tranny, pulling a 5er over the truck's rated capacity, drag racing, etc. no problems. believe whom you want. i strongly suggest you research further. and for the record, the lbz also has reports of overheating. but make sure you find out what the circumstances were. the lly is deemed an overheater, but that's only for those towing MAX capacity in the harshest condition. the same seems true with the lbz. fwiw.

do some more research. the lly overheat issue is not at 10k lbs. it has to do with large air damn/wind drag towing situations, in addition to a HEAVY load, in 100*+ weather up long steep grades. this means mainly large, TALL, 5th wheels, running near the max tow capacity of the truck (15k). i here the rumors often of the so called overheaters, as i have one. fact is, 90% of these rigs don't meet the requirments to overheat. but that's not good enough to beat the stigma.

my 5th wheel/truck combo has been scaled at 26k (gross is rated at 22k), is over 13' tall and got fairly warm, but never overheated. and i have power adders and push it hard. i've also drag raced it and ran a 14.5 et. i've added cooling capacity to it as a precautionary measure and have never had a problem?

stock tranny, pulling a 5er over the truck's rated capacity, drag racing, etc. no problems. believe whom you want. i strongly suggest you research further. and for the record, the lbz also has reports of overheating. but make sure you find out what the circumstances were. the lly is deemed an overheater, but that's only for those towing MAX capacity in the harshest condition. the same seems true with the lbz. fwiw.

Thanks Rusty... Iam at a tossup between a durmax (04.5 and up) or a gasser with the 6.0. I am not towing THAT much, and when Ido, it is a flatbed with a buggy or a fully decked out Super Sport Nautique heading up the summit. I have a few months to decide, but Iwant to make the right educated choice.

dima

http://www.pirate4x4.com/forum/showthread.php?t=598365

I dont know if your like me but if I were to get a Dmax I'd want the best (LBZ w/ 6 speed) but its gonna cost you lots of $$$$

I'm sure an older one with fixed injectors would be fine but it would sure suck being passed by newer LBZ's and missing out on the added mpg from the 6 speed.

It comes down to a money issue for me. If all the big 3 cost the same I would get a d-max lbz but there's a $10,000 difference between dmax and cummins.

I know your 2nd gen had left a bad taste in your mouth and that's why I think you should look into a newer babied diesel.

Like others said before if you want a really well care for newer dmax your gonna have to pay.

For me it would have to be a LBZ 6 speed or 05+ Cummins

I'm not that impressed on mildly modded older dmax's. My old 215hp 99 CTD with a edge and injectors blew past my buddy's LLY w/ edge on the freeway, as well as many other dmax kill story's.

If you can swing it get a LBZ

I dont know if your like me but if I were to get a Dmax I'd want the best (LBZ w/ 6 speed) but its gonna cost you lots of $$$$

I'm sure an older one with fixed injectors would be fine but it would sure suck being passed by newer LBZ's and missing out on the added mpg from the 6 speed.

It comes down to a money issue for me. If all the big 3 cost the same I would get a d-max lbz but there's a $10,000 difference between dmax and cummins.

I know your 2nd gen had left a bad taste in your mouth and that's why I think you should look into a newer babied diesel.

Like others said before if you want a really well care for newer dmax your gonna have to pay.

For me it would have to be a LBZ 6 speed or 05+ Cummins

I'm not that impressed on mildly modded older dmax's. My old 215hp 99 CTD with a edge and injectors blew past my buddy's LLY w/ edge on the freeway, as well as many other dmax kill story's.

If you can swing it get a LBZ

all depends on what is done to the d-maxes. no way your old 215hp Cummins with the Edge will come close to keeping up with my LB7 (with EFI)

all depends on settings, weight, and so forth...... you know that.

the 6 speed would be nice, but I certainly dont' care. the 5 speed is awesome as well and it'll last me forever!

this past trip I towed about 7500# (my rig and trailer) to Hot Springs and back to Chicago. the temps in AR were 105*+ and my temp gauge NEVER moved. we were towing around 75-80mph and it kept cool as a cucumber :D

the newer d-maxs are sweet, but don't look away from the LB7s if the injectors are already replaced. it's a great motor and is easy to make lots of power if needed/wanted.

I dont know if your like me but if I were to get a Dmax I'd want the best (LBZ w/ 6 speed) but its gonna cost you lots of $$$$

I'm sure an older one with fixed injectors would be fine but it would sure suck being passed by newer LBZ's and missing out on the added mpg from the 6 speed.

It comes down to a money issue for me. If all the big 3 cost the same I would get a d-max lbz but there's a $10,000 difference between dmax and cummins.

I know your 2nd gen had left a bad taste in your mouth and that's why I think you should look into a newer babied diesel.

Like others said before if you want a really well care for newer dmax your gonna have to pay.

For me it would have to be a LBZ 6 speed or 05+ Cummins

I'm not that impressed on mildly modded older dmax's. My old 215hp 99 CTD with a edge and injectors blew past my buddy's LLY w/ edge on the freeway, as well as many other dmax kill story's.

If you can swing it get a LBZ

Dan, that is EXACTLY why I am looking at the d-max. The old Dodge got me soooooo pissed off, that I don't know if Iw ant to go through that again.

As for the price on the d-max, my wife canhook me up with a dealer and I will get a smokling deal on one. She works with them on a daily basis, and has some of them that will find me the truck I want at their cost. We bought a X3 brand new for the best deal I have ever heard of.

I will look at a megacab with the older motor in it, but they still have the fueling issues. I am not goignt o buy a truck, and then drop anoter grand into it, jsut to make sure the fuel feeds right withouht air in it.

Dima

I'm not that impressed on mildly modded older dmax's. My old 215hp 99 CTD with a edge and injectors blew past my buddy's LLY w/ edge on the freeway, as well as many other dmax kill story's.

If you can swing it get a LBZ

lb7's are very capable on tuning only. There are a few canned tunes that will make 500rwhp on a stock lb7. The edge is one of the mildest tuners for a duramax. If that lilly had a ppe,tts or something equal it would have been a different story. Your dodge must have been pretty quick though because a edged/lly will run high 14's which would be tough for a 24 valve/edge/injected cummins to run.

Dima, get a Diesel. Dont get a gasser. If you do any towing even if it's just once a year it's worth it. I have no problem sending my wife out with my D-max loaded down with 3 quads and the Jeep on there too. Every year she takes it over the the pass on Hyw 80 with no problems, AC and cruise controll on. It will make every towing trip much more of a stress free drive, no worring about getting a running start at the hills, or getting stuck behind and then passing a slow big rig. And FWIW I dont have any overheating problems.

I work at a GMC dealership in the San Diego. I rarely see a Sierra DMax (any model year) with an overheat complaint. I've got some customers that pull overloaded toy boxes to the desert with lifted rigs, stock gears. Some are chipped, some aren't.

Not sure what the conditions are that people are experiencing overheat.

My 01 CC/short bed runs 315/75/16's, factory gears, recently added an Edge Juice/Att. I've never experienced overheat conditions, EGT's are my limiting factor. I regularly pull a 10k# enclosed trailer all over SoCal.

EGR valves are sure taking a shiat at low miles on the 06/07 Classics/Savana vans, I get a couple of those a week.

bob01yj, do you know of or is there a way to find out if there is a service buliton on the daytime running lites overheating and melting the bulb holder? One of mine just went out and when I changed it the plastic socket is all dark brown around where the bulb plugs in and the outter most portion is no longer round form the melting. I checked and the passenger side is the same. This is on a 05' CC D-max with 50k mi. :confused:

How does the 5 speed Allison compare to the 6 speed?

lb7's are very capable on tuning only. There are a few canned tunes that will make 500rwhp on a stock lb7. The edge is one of the mildest tuners for a duramax. If that lilly had a ppe,tts or something equal it would have been a different story. Your dodge must have been pretty quick though because a edged/lly will run high 14's which would be tough for a 24 valve/edge/injected cummins to run.

Yeah it was quick.....and ran 14.6's before I added the 200hp Mach 5 injectors.

First off the race of my 99 vs LLY w/ edge..

My 99 was very quick and fast. Full billet DTT trans, Edge Drag comp, and Don's 200hp Mach 5 injectors. Doesnt sound like much but adding 200hp injectors will turn any truck into a rocket.

We never drag raced but the one time I took the ole 99 to the track was before the 200hp injectors and it still ran a 14.6 doing a 20psi boosted launch with the Edge + tranny.

The race was from about 75+mph and after 90 the dmax fell on its face and I flew past him.

I'm not knockin d-max's I just said I wasnt impressed with LLY's with mild tuning.

Flatty what fueling issues are you talking about with the CR 5.9L

I love my 03 but wish I would of bought a 04.5+ after I learned more about common rails. The 04.5-07 are cabeable of way more hp per dollar then the 03-04.

I guess im a snob and dont like that fact that there are better model years out there.

If my 03 HO 6 speed was a 05 with a built auto it would easily have 80-100 more rwhp and be well into the 13's but its not.

Get exactly what you want or you will have regreats

The race was from about 75+mph and after 90 the dmax fell on its face and I flew past him.

GM HDs are governed to 97 mph, and although the Edge can change that the trucks still aren't geared for too far above 100. And honestly, how much time would you really spend above 100?

How does the 5 speed Allison compare to the 6 speed?

Basically it is the same transmission with a different tcm. They did some upgrades to it basically copying the trans go kit and the vlave body is a little different but for the most part it is the same transmission. It will hold more power than the 5 speed due to the upgrades. JFYI, you can convert a 5 speed ally to a 6 speed. The only difference would be no m mode.

bob01yj, do you know of or is there a way to find out if there is a service buliton on the daytime running lites overheating and melting the bulb holder? One of mine just went out and when I changed it the plastic socket is all dark brown around where the bulb plugs in and the outter most portion is no longer round form the melting. I checked and the passenger side is the same. This is on a 05' CC D-max with 50k mi. :confused:


They sell new sockets with pigtails that you have to splice in. Been happening to Sierra's/Yukon's and their Chevy bretheren for 6-7 model years now with no true fix.

My truck is a compromise between a daily driver/tow rig/desert racing chase truck. It pulls my enclosed trailer with power to spare in all but prolonged 6%+ grades. The grade's up Hwy 62 going into Yucca Valley on the way to the Hammer's is the only hill that REALLY works the truck while towing. In CA, where most of my driving is done, 55 while towing is the speed limit, $471 fine for exceeding 55 while towing, ask me how I know. I'm just not in that big a hurry to get there anymore.

Truck does a fair job (when aired down) on typical Baja/Lucerne Valley roads that chase trucks encounter (RCD 6" lift). Truck weighs 7500#'s or so loaded, it ain't gonna be a go faster on washboards no matter what I do to it.

All this talk about issues with dfferent trucks, I am going cheap on this. I can't swing the cost of a duramax, nor will I get any cumins under a 04.5 I am not a big fan of the new powerstroke, so I am getting a 95-97 Powerstroke F350 with a manual. My wife is on the lookout for one. Now I just have to figure out how to pump them up.

Dima

Don't be scared of a used Dmax, my 01 has no cat, vacuum pump or EGR valve.
Injectors are warranteed for 7 years/200k, no deductable.

GM HDs are governed to 97 mph, and although the Edge can change that the trucks still aren't geared for too far above 100. And honestly, how much time would you really spend above 100?


mines set for 158 (not that I can hit that) and I probably see 100+ atleast once a week :D

I like to drive fast, but I'm careful about it (as careful as you can be at higher speeds)

I have the best of both worlds and love it (rockcrawler and go fast in a straight line)

good luck with your choice and enjoy!! :smokin:

how do the 5 speeds drive at freeway speed, what speed do you cruise at on the freeway?

All this talk about issues with dfferent trucks, I am going cheap on this. I can't swing the cost of a duramax, nor will I get any cumins under a 04.5 I am not a big fan of the new powerstroke, so I am getting a 95-97 Powerstroke F350 with a manual. My wife is on the lookout for one. Now I just have to figure out how to pump them up.

Dima

They have trans issues

All this talk about issues with dfferent trucks, I am going cheap on this. I can't swing the cost of a duramax, nor will I get any cumins under a 04.5 I am not a big fan of the new powerstroke, so I am getting a 95-97 Powerstroke F350 with a manual. My wife is on the lookout for one. Now I just have to figure out how to pump them up.

Dima

Honestly, a '01 Duramax is close to bulletproof. If the injectors are new, then you're good to go.

how do the 5 speeds drive at freeway speed, what speed do you cruise at on the freeway?


IMO< it cruises really nice. mine seems to have a nice "sweet spot" at 80mph. it just likes to settle there and cruise. now, this is with some tuning done, so I'm not sure if stock would be the same.

I still get a solid 16mpg with my foot in it all the time. x2 on what focker said ('01-02)

GM HDs are governed to 97 mph, and although the Edge can change that the trucks still aren't geared for too far above 100. And honestly, how much time would you really spend above 100?


Edge is actually one of the few chips that you cant remove the speed limiter with.

how do the 5 speeds drive at freeway speed, what speed do you cruise at on the freeway?

Mine cruises at around 2250-2300 rpm at about 80. (5 speed). The 6 speed tranny just adds a 2nd overdrive, leaving the first 5 gears almost the same. 5th is around .81 to 1, and 6th is only .7 or so to 1, not much of a reduction. People say its good for 250-300 rpm, so 6 speeds cruise about 2000 rpm at 80.

I am looking at an 04 with 52k on it. It has been lifted with an edge chip since it was new. How well do these trucks put up with the programmers and how easy is it to remove if I need to take it to the dealer.

They have trans issues

On the autos. The ZF is a STOUT tranny. I will swap in a centerforce clutch, and be good (I think).

Dima

I am looking at an 04 with 52k on it. It has been lifted with an edge chip since it was new. How well do these trucks put up with the programmers and how easy is it to remove if I need to take it to the dealer.


Haha are you seriously considering a used lifted and bombed diesel...

Some people just dont get....

Go find one that some old guy wipes down with a diper ever night instead of some 20 something ass hole that drove it around with the edge on 5 for the past 3 years and wants to sell it.

Lifted + Edge = abused for its entire life

I am not a big fan of the new powerstroke, so I am getting a 95-97 Powerstroke F350 with a manual. My wife is on the lookout for one. Now I just have to figure out how to pump them up.

Dima


even worse idea.......

Even though I regreat it, im still happy with my 03HO 6 speed because nothing has gone wrong with it. So it wont win any drag races but it hauls ass on the freeway and I dont have to worry about tranny issues since I bought a manual since I believe you should never buy a used auto.

I throw down on my truck everyday and it still keeps purring.

2 dyno's
2 wensday night drags
countless redline shifts and triple digets twice a week

If you can find a nice 03HO 6 speed for $20K get it

even worse idea.......

Even though I regreat it, im still happy with my 03HO 6 speed because nothing has gone wrong with it. So it wont win any drag races but it hauls ass on the freeway and I dont have to worry about tranny issues since I bought a manual since I believe you should never buy a used auto.

I throw down on my truck everyday and it still keeps purring.

2 dyno's
2 wensday night drags
countless redline shifts and triple digets twice a week

If you can find a nice 03HO 6 speed for $20K get it

Yup, but you just said it... 20g's. I can't swing that cost right now unless I want to get rid of the buggy... I am NOT doing that this time around. I will get the older PS for cheaper and roll that for now.

Dima

I am looking at an 04 with 52k on it. It has been lifted with an edge chip since it was new. How well do these trucks put up with the programmers and how easy is it to remove if I need to take it to the dealer.

How much lift does an Edge chip give? If I an get a chip that lifts my truck 4", I want it.... ONLY after I swap out the muffler bearings... Those are a bit pricey.

Dima

Haha are you seriously considering a used lifted and bombed diesel...

Some people just dont get....

Go find one that some old guy wipes down with a diper ever night instead of some 20 something ass hole that drove it around with the edge on 5 for the past 3 years and wants to sell it.

Lifted + Edge = abused for its entire life
I am considering it because:

It is in my price range
There isnt much else available that is in my price range
I will probably lift what ever I buy
If the duramax is any where near the burlyness of my Dodge it wont be a big deal


The edge chip makes it fit 35's and it is plug and play. No wrenches required. :flipoff2:

A lifted truck with a chip has probably toasted the tranny. The ally is good for maybe 100hp over stock, however when you add larger tires that decreases. The ally will go into "limp mode" when it senses trans slip, this is to keep it from completely dying, it basically limits the truck to a few gears and decreases engine power. With each limp it will do it easier and easier. I garauntee it has been limped.

A lifted truck with a chip has probably toasted the tranny. The ally is good for maybe 100hp over stock, however when you add larger tires that decreases. The ally will go into "limp mode" when it senses trans slip, this is to keep it from completely dying, it basically limits the truck to a few gears and decreases engine power. With each limp it will do it easier and easier. I garauntee it has been limped.

You dont know that it has been limped for sure. All trannies are different some will put up with an additional 100rwhp some dont. Just pull the dipstick and see what the tranny fluid looks like. If it limped there will definatley be darker fluid. The week link is the converter and the c3's if those get toasty you will definately see it in the fluid. If you are planning on putting more power to it you will need a tripple disk converter and a trans go kit minnimum.

Mine is lifted and chipped (Edge), never been in limp mode. It's never been set above 3 for more than a few minutes of playing either though. It's a 3/4 ton truck, not a sports car or dragster.

Thanks for the info guys. Looks like I am passing on this one...

You dont know that it has been limped for sure. All trannies are different some will put up with an additional 100rwhp some dont. Just pull the dipstick and see what the tranny fluid looks like. If it limped there will definatley be darker fluid. The week link is the converter and the c3's if those get toasty you will definately see it in the fluid. If you are planning on putting more power to it you will need a tripple disk converter and a trans go kit minnimum.



you also don't know that it hasn't been limped for sure. i've limped my tranny a few times and there is no signs of tranny fluid color/odor change. that is no way to tell if it's been limped, imo.

are you saying some 5 speed allys will only handle 100hp gains and other 5 spds will handle 200hp gains??????

Basically it is the same transmission with a different tcm. They did some upgrades to it basically copying the trans go kit and the vlave body is a little different but for the most part it is the same transmission. It will hold more power than the 5 speed due to the upgrades. JFYI, you can convert a 5 speed ally to a 6 speed. The only difference would be no m mode.

Could you post up a little more info on this - parts required or just programming, etc?

From suncoast's web site




Includes: Sun Coast Engineered Valve Body, Solenoids, Sump Filter, Allison Spin-on Filter. This kit includes smart clutch control valves for increased durability. The Sun Coast Engineered Valve Body is a certified-tested valve body assembly. No sticking valves here!ALLISON 5 SPEED TO 6 SPEED
2001-05
Part No. A1-6VB-TCM
Price: $1648.00*
CONVERT YOUR 2001-2005
ALLISON 5 SPEED TO 6 SPEEDS
Drops 325 engine rpm @ 75 mph with 3.73 gears. Increases fuel economy 1 - 1.5 MPG, reduces engine noise while cruising, a truck with 3.73 gears that normally likes cruising at 62 MPH will now cruise nice at 72 MPH. The gear ratio in your 5 speed is .71 and our 6th gear will be .61. 6th gear can be disabled with your two haul button and 5th canceled with OD off. Requires valve body and tcm change (1 hour). No wiring, no modifications required. Indicate LB7 or LLY & year.

Mine cruises at around 2250-2300 rpm at about 80. (5 speed). The 6 speed tranny just adds a 2nd overdrive, leaving the first 5 gears almost the same. 5th is around .81 to 1, and 6th is only .7 or so to 1, not much of a reduction. People say its good for 250-300 rpm, so 6 speeds cruise about 2000 rpm at 80.

5th is .71
6th is .61

;)

you also don't know that it hasn't been limped for sure. i've limped my tranny a few times and there is no signs of tranny fluid color/odor change. that is no way to tell if it's been limped, imo.

are you saying some 5 speed allys will only handle 100hp gains and other 5 spds will handle 200hp gains??????

I have yet to see a limped tranny with perfect fluid. I never even limped the tranny in my first duramax yet the fluid was still ugly. But if you say that yours did, I guess it's possible. I have never said a stock 5 speed ally will hold 200hp gains. I dont know where that came from. I simply said some will put up with 100rwhp gains and others wont.